SOVIET ATOMIC ENERGY VOLUME 18, NUMBER 2

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Declassified and Approved For Release 2013/09/24: CIA-RDP10-02196R000700010002-5 Volume 18, Number 2 ? February, 1965 SOVIU TOMIC ENERGY.' ATOMHAFI 3HEPIWA (ATOMNAYA iNERGIYA) TRANSLATED FROM RUSSIAN CONSULTANTS BUREAU , Declassified and Approved For Release 2013/09/24: CIA-RDP10-02196R000700010002-5 Declassified and Approved For Release 2013/09/24: CIA-RDP10-02196R000700010002-5 EFFECTS OF RADIATION ON SEMICONDUCTORS - By S. V. yavilov \ Devoted to the effects of .electromagnetic and, torpuscular radiations on semiconductors, this new volume deals with the processes of absoeption of electromagnetic radiation, photoionization and ionization by charged high-energy par- ticles, and the principal types of recombination processes ,bY which an excited crystal returns to its original equilibrium state. Translated from the Russian., ' 238 pages , CB 1965 MOSSBAUER - EFFECT ?? METHODOLOGY $1,5.00 A CERAMIC ACOUSTIC DETECTORS By A. A. Anan'eva - 4 Deals' with the dielectric and piezoelectric properties: of ' barium-titanate cerarnics,lthe methods of determining sound receiver characteristics, and the experimental development of nondirectional wideband sound receivers employing sphe- rical and cylindrical shells of barium-titanate ceramic polar- ized in various ways. Wideband sound receivers using plane , diaphragms end the development of receivers responsive to certain resonance frequencies in the working frequency band ? and therefore of high sensitiVity are described in detail. Includes a bibliography on the developMent of, piezoelectric \elements fdr the design and construction, of acoustic re: ,ceivers.- A Special Research Report translated,' from the Russian. " ? -0 130 pages CB 1965 ' $22.50 QUANTUM .ELECTRON THEORY OF AMORPHOUS CONDUCTORS t By A. I. Gubanov k This Is the first monograph to deal .with the physics of amorphous electronic conductors. It includes a critical review of the electrical properties and`structure of liquid and glassy semiconductors, a separate chapter on the fundamentals of the quantum 'electron theOry of solids: and a consideration of the similarities and differences between the structures of liquid and crystalline substances. Using One-dimensional models, Gubanov deduces the band structure of the electron theory spectrum and extends the theory for three-dimensional models. Also ncluded are discussions of characteristic fea- tures of elictron scattering in amorphous substances,' the Mean free path of electrons and the temperature dependence of various galvano-thermomagnetic coefficients of an amor- phous substance, and the author's theory of amorphous ferromagnets. Translated from the Russian. 4 293 pages CB 1965 fi By Irwin J. Gruverman Reviews applications and describes a methodology permitting scientists in all fields to understand the complexities of equip-, .`ment reqUired for velocity modulation, measurement of 'effects, and modification of external environments. Establishes a basis for evaluating the applicability of MOssbauer-effect studies to various areas'. The four sections of the book include: Re- views of applications in physics, biology,' and chemistry; Three alternative approaches .to velocity modulation; Meas- urement and calibration; and Environmental control with respect to magnetic fields, temperature, and pressure. Excel- ? lent as supplementary reading in undergraduate and graduate ? nuclear' physics courses, this volume is also valuable as e text in experimental advanced physics. . Approx. 200 pages PP 1965 $12.50 $17.50 SOVIET RESEARCH IN, NEW SEMICONDUCTOR MATERIALS Edited by D. N. Nasledov et -el. Five internationally known Soviet researchers on semicon- ductor materials ? Nasledov, Goryunova, Aeger , Lange, and Radautsan ? participated in selecting. those 18 refiorts, pre- sented at a 1963 Academy of Sciences conference -on new -semiconductor materials. The editors are themselves authors or co-authors of ten of the, reports. The studies include: properties of 'solid solutions based on materials with a zinc blende type structure, both chain land layer modifications; change of the charge 'carrier mobility upon melting of semi- conductors; anisotropy of the electrical and galvanomagnetic properties of certain semiconductor materials; and the elec- trical and,optical properties of thin semiconductor layers. A Special Research Report translated from the Russian.? 127 pages ? , CB 1965 , $17,50 ((:\ / CONSULTANTS BUREAU/CP PLENUM PRESS )/ 227 West 17th Street. New York. New York 10011 ? 1 J Declassified and Approved For Release 2013/09/24: CIA-RDP10-02196R000700010002-5 Declassified and Approved For Release 2013/09/24: CIA-RDP10-02196R000700010002-5 ATOMNAYA EN.ERGIYA EDITORIAL BOARD A. I. Alikhanov A. I. Leipunskii A. A. Bochvar M. G. Meshcheryakov N. A. Dollezhal' M. D. Millionshchikov K. E. Erglis (Editor-in-Chief) V. S. Fursov I. N. Golovin V. F. Kalinin N. A. Kolokol'tsov (Assistant Editor) A. K. Krasin I. F. Kvartskhava A. V. Lebedinskii I. I. Novikov V. B. Shevchenko A. P. Vinogradov N. A. Vlasov (Assistant Editor) M. V. Yakutovich A. P. Zefirov SOVIET ATOMIC ENERGY A translation of ATOMNAYA iNERGIYA A publication of the Academy of Sciences of the USSR @ 1966 CONSULTANTS BUREAU ENTERPRISES, INC. 227 West 17th Street, New York, N.Y. 10011 Volume 18, Number 2 February, 1965 CONTENTS Penetration of Hydrogen Ions H1-1- into the Surface of Stainless Steel ?E. S. Borovik, P A ENG. G E RUSS. N. P. Katrich, and G. T. Nikolaev 113 91 Perturbation of Particle Motion in the Stellarator?A. P. Popryadukhin 118 96 Experiments on the Buildup of Electrons in the Synchrotron?Yu. M. Ado, E. G. Bessonov, and P. A. Cherenkov 129 104 Angular and Energy Characteristics of the Neutrons Emitted in U235 Fission? M. V. Blinov, N. M. Kazarinov, and A. N. Protopopov 133 108 Calculation of Average Radiative Capture Cross Sections for Neutrons with Energies of 103-105 eV ?A. G. Dovbenko, S. M. Zakharova, V. E. Kolesov, and A.V. Malyshev . 140 114 Asymptotic Formulas for Scattering of Slow Neutrons on Bound Atoms ?V. F. Turchin and V. A. Tarasov 146 118 The Attenuation of Reactor Radiation by Means of Serpentine Concrete?G. A. Vasil'ev, A. P. Veselkin, Yu. A. Egorov, V. A. Kucheryaev, and Yu. V. Pankrat'ev 151 121 Study of the Neutron Moderation Process in Beryllium and Beryllium Oxide by a Pulse Method ?I. F. Zhezherun 158 127 Experimental Investigations of Shields on the Riz Stand?S. P. Belov, V. A. Dulin, Yu. A. Kazanskii, V. I. Popov, and S. G. Tsypin 167 136 A Whole-Body Counter?Yu. V. Sivintsev, 0. M. Arutinov, V. A. Kanareikin, and M. A. Panov. 173 141 Variation of the Separation Factor in Isotope Exchange as a Function of the Properties of the Molecules Being Exchanged?A. M. Rozen and A. I. Mikhailichenko 180 147 Prospective Developments and Economics of Nuclear Power Generation? B. B. Baturov and N. M. Sinev 191 157 Chemistry of Nuclear Fuel Reprocessing?V. N. Prusakov and M. F. Pushlenkov 210 171 LETTERS TO THE EDITOR Homogeneous Critical Assembly with a Profiled Fuel Charge?A.K.Krasin and E.I. Inyutin 215 175 Angular Distribution of Collimated Radiation? g. F. Fomushkin 219 178 Diffusion of Neutrons in Spin-Orbit Interaction?Yu. N. Kazachenkov and V. V. Orlov 222 179 Characteristics of Asymptotic Spectrum of Neutrons in Uranium?A. A. Malinkin, F. Nasyrov, and V. F. Kolesov 225 181 Excitation Function of Reaction Cu65(d,2n)Zn65 and Yield of Isotope Zn65?P.P.Dmitriev and N. N. Krasnov 228 184 Use of Aqueous Glycine Solution for 'Y -Ray and Fast-Neutron Dosimetry ?A. P. Ibragimov and A. V. Tuichiev 231 185 Annual Subscription: $ 95 Single Issue: $30 Single Article: $15 All rights reserved. No article contained herein may be reproduced for any purpose what- soever without permission of the publisher. Permission may be obtained from Consultants Bureau Enterprises, Inc., 227 West 17th Street. New York City, United States of America. Declassified and Approved For Release 2013/09/24: CIA-RDP10-02196R000700010002-5 Declassified and Approved For Release 2013/09/24: CIA-RDP10-02196R000700010002-5 CONTENTS (continued) Light Output and Amplitude Resolution of Monocrystals?G. V. Miroshnikov PAGE EN6. I ?RUSS. and A. I. Kirillov 234 187 Some Data on Equilibria of the Systems MeS(MeS2)-UO2SO4-H20 at Elevated Temperatures and Pressures?B. S. Osipov and R. P. Rafal'skii 237 189 SCIENCE AND ENGINEERING NEWS International Betatron Colloquium?A. A. Vorob'ev, V. A. Moskalev, M. F. Filippov, and V. A. Vorob'ev 240 192 Conference on the Physics and Technology of Alkali Halide Scintillators ?R.V.Bakradze and Yu. A. Tsirlin 243 193 "Atomic Energy" Pavilion at the 1964 Exhibit of Achievements of the USSR National Economy ?L. I. Petrenko 245 194 BIBLIOGRAPHY New Books 249 198 The Russian date "Podpisano k pechati" of this issue was 1/ 21/ 65. This is equivalent to "approved for printing ." Publication did not occur prior to this date, but must be assumed to have taken place reasonably soon thereafter. Publisher Declassified and Approved For Release 2013/09/24: CIA-RDP10-02196R000700010002-5 * Declassified and Approved For Release 2013/09/24: CIA-RDP10-02196R000700010002-5 PENETRATION OF HYDROGEN IONS H1+ INTO THE SURFACE OF STAINLESS STEEL (UDC 533.9) E. S. Borovik, N. P. Katrich, and G. T. Nikolaev Translated from Atomnaya tnergiya, Vol. 18, No. 2, pp. 91-96, February, 1965 Original article submitted July 15, 1963, and in final form June 22, 1964 A system for conducting experiments on the coefficient of penetration is described. The use of hydro- gen and helium condensation pumps secures an ultrahigh vacuum in the apparatus. The coefficient of penetration of 35 keV H1+ ions is determined. For an ion density in the region of 1019 to 2 ? 1019 the coefficient of penetration equals 0.93 and is independent of the number of such ions. Recently the process of gas ion penetration into various materials has caught the interest of many physicists studying hot plasma. This is because in magnetic traps with the injection of fast particles the maintenance of ul- trahigh vacuum depends substantially on the coefficient of penetration. So far this coefficient has been measured in few investigations: for 150 to 2600 eV H&- ions in [1], and for 7 to 25 keV He and D+ ions in [2]. Some quan- titative characteristics of the penetration process have been given in investigations into the desorption of previously penetrating particles caused by ion bombardment [3-5] and in connection with the development of methods of pre- paring solid gas targets and the separation of isotopes [6, 7]. None of these investigations, however, was carried out in vacuum conditions ensuring clean surfaces for the bombarded targets. We here present the first measurements of the penetration coefficient of 35 keV H1+ into a 1Kh18N9T stainless steel target. The vacuum conditions under which these measurements were made ensured that the target surface bombarded would be quite clean. Description of Apparatus The exterior view of the apparatus with which the measurements were made appears in Fig. 1. The arrange- ment of the main parts of the apparatus as they appear along the direction of motion of the H1+ ion beam is shown in Fig. 2. The hydrogen ion beam produced by means of a high frequency ion source 1 was focused by the electro- static lens 2, accelerated to 35 keV in the accelerator tube 3, and, via the first collimating system 8, 9, fell into the magnetic analyzer chamber 11. In this chamber the H1+ hydrogen ions were turned through 60?, and by way of a second collimating system 15, 17 fell into the measuring chamber 18 and on to the target 21. The high frequency ion source with the electrostatic lens made it possible to obtain a well focused beam of H1+ ions of up to 120 (current density at target up to 160 MA/cm2). The consumption of hydrogen in the high frequency ion source, de- termined by the geometry of the extracting electrode, did not exceed 1.5 cm3/h. This hydrogen consumption may be regarded as small compared with that in other types of ion source. However, in systems requiring the mainte- nance of a vacuum of the order of 10-7 N/m2, such gas loadings are very high, since the corresponding pumping rates required must exceed 3 ? 105 dm3/sec. The pumping rates may be reduced to a few tens of thousands of dm3/sec if the differential pumping method is employed. However, even these pumping speeds are very difficult to achieve with diffusion pumps, not to men- tion the contamination of the receiver. In view of this, we used the multistage condensation method of pumping [8], which guaranteed the necessary pumping rate, high vacuum stability, and a fairly clean target. Figure 2 shows the disposition of the helium condensation pumps (HCP) 10, 14, and 16. Each pump comprises a copper vessel of 0.5 drn3 capacity, with calculated pumping rate 1.2 ? 104 dm3/sec. The limiting HCP vacuum, determined by the hydrogen saturated vapor tension, becomes quite high if the temperature of the pump surface is reduced below the 113 Declassified and Approved For Release 2013/09/24: CIA-RDP10-02196R000700010002-5 Declassified and Approved For Release 2013/09/24: CIA-RDP10-02196R000700010002-5 Fig. 1. Exterior view of the apparatus; 1, 2) diffusion oil vapor pumps M-500 and M-2500, respectively; 3, 4) heated and unheated vacuum valves, respectively. 15 23 17 18 14 13 10 5 (pt.) 01 9 ?-- 15 12 11 9 8 lJIIlHJIJJIJJJ 111111111m111 Fig. 2. Arrangement of apparatus. II tinuous pumping of the vapor above the liquid helium. increase in their period of operation (8 to 10 h). In our apparatus, besides the HCP, we used two hydrogen condensation pumps 7 and 20 with capacity 0.5 dm3 each, and two oil diffusion pumps M-500 and M-2500 (see Fig. 1). The M-2500 pump was intended for conditioning the vacuum system and for the preliminary evacuation of hydrogen coming from the high frequency ion source into chamber 4 during the experiment. The M-500 pump was intended for conditioning the measuring chamber 18. Both pumps had water and nitrogen shielding, and in case of need could be shut off from the rest of the system by means of the valves shown in Fig. 1. In the lower part of the chamber 4 was placed a nitrogen louver trap; fixed to this was a copper screen 5 separated into two sections by the barrier 6. The right hand side of the screen constituted a chamber communicating with the diffusion pump through the nitrogen trap. Inside this was placed a hydrogen con- densation pump 7 intended for pumping out stray gases. The left hand half of the nitrogen screen constitutes a cham- ber closed on all sides and communicating with the right hand half of the nitrogen screen and with the magnetic boiling point of liquid helium. The necessary fall in sur- face temperature can easily be achieved by pumping out the vapor over the liquid helium. In our pumps the vapor was pumped out to about 18 N/m2, corresponding to a lim- iting vacuum of ????1 ? 10-10 N/m2 [9]. The duration of ser- vice of the HCP was determined by the thermal loading and the amount of helium introduced. The priming of the condensation pumps with liquid helium by the ordinary method of pouring over under pressure did not give good results. The amount of helium so introduced was small and hence so was the duration of service. In view of this, we set up a special arrangement for pouring; this enabled the operation to be effected with con- This secured reliable priming for the HCP and a consequent 114 Declassified and Approved For Release 2013/09/24: CIA-RDP10-02196R000700010002-5 Declassified and Approved For Release 2013/09/24: CIA-RDP10-02196R000700010002-5 analyzer chamber by means collimating tubes 8 and 9. Col- p, N/m2 limator tube 8 (diameter 14 and length 250 mm) had an entrance aperture of diameter 12 mm and was soldered into the partition of the nitrogen screen. Collimating tube 9 10-6irr 6 4 (diameter 11 and length 150 mm) with an entrance aperture 9 mm in diameter connected the left hand half of the nitro- 2gen screen to the magnetic analyzer chamber. This geo- 6 4 2 10-7 metry of the collimating system ensured a smallish conduc- 40 50 t, mm tivity between the chambers, sslightly lowering the hydrogen Fig. 3. Measuring chamber pressure as a function of ion beam current. Within the left hand part of the screen was placed HCP 10 with a hydrogen pumping rate of 1.2 ? 104 dm3/sec. Thus the two condensation pumps bearing the main load during the experiment were located in a comparatively small volume, and the possibility of impurity gases passing into the measuring chamber from the unheated part of the apparatus was almost entirely eliminated. The magnetic analyzer chamber 11 was made of stainless steel 1Kh18N9T and was assembled by means of poly- fluorethylene resin gaskets. The pole tips of the magnet 13 were situated inside the chamber, while the rest of the magnet was outside. The magnetic analyzer chamber had a nitrogen screen 12, inside which was HCP 14. The hydrogen ions H2+ and H3+ and fast neutral particles coming out of the high-frequency ion source and falling into the magnetic analyzer chamber partly passed into the.nitrogen screen, while the remaining particles were pumped away by the HCP. The Hi+ ions passed out of the magnetic analyzer chamber through collimating tube 15, an ap- erture in the nitrogen screen 23, and tube 17, into the measuring chamber, and on to the target. The nitrogen screen comprised a cylindrical chamber joined to the measuring chamber by a tube 17 of given conductivity. In the upper part of the nitrogen screen, over the path of the beam, was placed HCP 16, intended for pumping out the measuring chamber and protecting it from the onslaught of hydrogen from the magnetic analyzer chamber. Measuring cham- ber 18 and the components connected to it were made of stainless steel and assembled with copper gaskets com- pressed between conical surfaces. This construction facilitated heating to temperatures of 400 to 450?C. Below the measuring chamber was placed the heated metal valve (see Fig. 1) separating the measuring chamber from the oil diffusion pump M-500. The target of the material to be studied was fixed in a copper block, which is turn was fixed to holder tube 22. The open end of the holder tube enabled the target to be cooled during bombardment. The Hi+ ion beam cur- rent was measured by a mobile Faraday cylinder 19. The vacuum in the measuring chamber was measured by an open ionization manometer of the Bayard-Alpert type placed inside the measuring chamber. The hydrogen conden- sation pump and screen 20 surrounding the target were intended to protect the target from the impact of stray gases. 10 20 30 time. 0) Initial pressure. Preparation of the Apparatus for Measurements The measuring chamber and valve separating it from the diffusion pump were heated before beginning the experiment to some 400?C for 3 to 4 h. The apparatus was pumped during this heating by the oil diffusion pumps with nitrogen traps and the hydrogen condensation pump 7. When the heating ended, the vacuum in the measuring chamber had reached 1.3 ? 10-5 N/m2. After removing the heaters, liquid hydrogen was poured into hydrogen condensation pump 20. The temper- ature of the measuring chamber and the hydrogen condensation pump at this moment still stayed around 400?C. The total consumption of liquid hydrogen in this was 5 dm3. Simultaneously the measuring chamber was disconnected from the oil diffusion pump and nitrogen screen by means of the valve. This guarded the measuring chamber from oil decomposition products and reduced the residual gas background to a minimum. The vacuum in the measuring chamber immediately after pouring in the hydrogen reached 4 to 5 ? 10-7 N/m2. The pouring of liquid helium into the HCP 16 improved the vacuum in the measuring chamber almost instantaneously to 1.3 ? 10-7 N/m2, and then continued improving more slowly, so that after 1 to 1.5 h it reached 6 ? 10-8 N/m2 (5 ? 10-15 torr). The experiments, however, normally began immediately after pouring the liquid helium at a vacuum of 1.3 ? 10-7 N/m2..Here it was assumed that the main residual gas in the measuring chamber was hydrogen. This assumption was quite legitimate, remembering the presence of the hydrogen condensation pump in the measuring chamber, having a fairly high pump- ing rate and the capacity of removing all impurity gases except those condensing with difficulty at 20.4?K. This procedure of preparing for experiments ensured a fairly clean target surface and almost entirely excluded the possi- bility of contaminating this after heating by adsorption from the surrounding medium. 115 Declassified and Approved For Release 2013/09/24: CIA-RDP10-02196R000700010002-5 Declassified and Approved For Release 2013/09/24: CIA-RDP10-02196R000700010002-5 W, dm3/sec 100 50 0 IL) -0.95 0.9 2 ? -1" 06 6 81016 2 6 6 81017 2 4 6 81018 Fig. 4. Pumping rate W and penetration coef- ficient T1 as functions of the amount of gaseous hydrogen coming into the measuring chamber. 1) Total rate of pumping hydrogen from the measuring chamber; 2) calculated hydrogen pumping rate for the HCP; 3) penetration coef- ficient. Results of Measurements and Discussion The method of measuring the penetration coefficient was as follows. The beam of H1+ ions bombarding the target pene- trated into it. The flow of hydrogen from the target due to the nonpenetrating part of the beam as well as hydrogen diffusely emitted from the target altered the vacuum in the measuring chamber. A typical curve relating the vacuum to target bom- bardment time for a 35 kV, 110 ?A H1+ ion beam appears in Fig. 3. It should be noted that the change in pressure in the measuring chamber caused by the ion beam passing into the magnetic analyzer chamber is negligibly small. The pressure varies only on bombardment of the target. Knowing the ion beam current, the vacuum in the meas- uring chamber, and the rate of pumping hydrogen from the latter, we may determine the pentration coefficient; (P? Po) TV -= 1 105i+/e ' where n is the number of particles in 1 drn3 under normal con- ditions, p is the working pressure in N/m2,. Po is the initial pres- sure in N/m2, W is the pumping rate in dm3/sec, i+ is the ion beam current A, e is the charge on the electron in C, and 105 is the atmospheric pressure in N/m2. In the first experiments the penetration coefficient of the H1+ ions calculated for a pumping rate of 8 dm3/sec, determined by the conductivity of the tube, was very high, and at the beginning of the bombardment reached a value close to unity (0.99). As the density of penetrated particles rose, the penetration coefficient fell to 0.94 and then remained constant. This was the first time such a high penetration coefficient of ions had been obtained. In view of this the idea arose that extra hydrogen had been extracted by the clean surface of the chamber walls and by the hydrogen condensation pump 20. In order to check this idea, the pumping rate was measured. This was done by using the steady flow of hydrogen through a capillary of known conductivity. The measurements showed that the clean surfaces of stainless steel and copper did not possess any marked extraction rate between room temperature and 78?K. The clean surface of the hydrogen condensation pump, however, which was made of copper, did extract hy- drogen at liquid hydrogen temperature (20.4?K). As the amount of extracted hydrogen rose, the extraction rate ra- pidly fell, and at concentrations corresponding to approximately 0.01 monolayer practically vanished. This effect had not been observed by anyone before, and was rather unexpected for such low pressures. Figure 4 shows the ex- perimental curve 1 of the pumping rate as a function of the amount of hydrogen coming into the chamber. The calculated hydrogen pumping rate of the HCP 16, determined by the conductivity of tube 17 (see Fig. 2), is shown dotted. The deviation between the experimental (10 dm3/sec) and calculated (8?1.5 dm3/sec) values of pumping rate in the region N> 1017 lies within measuring error. During the bombardment, atomic hydrogen is present in the chamber, and the adsorption of this differs from that of molecular hydrogen. In view of this, we made some experiments to determine the amount of hydrogen ad- sorbed during bombardment at 20.4 and 78?K, desorbing it by heating the hydrogen pump and screen 20. It was established that the adsorption of atomic and molecular hydrogen took place only at temperatures below 30?K and stopped almost completely for amounts of adsorbed hydrogen roughly equal to 0.01 monolayer. The total amount of desorbed hydrogen agreed with the calculated value. Furthermore these experiments showed that a certain quan- tity of heavier materials (1 to 210 of the number of incident ions) were evolved by the target during bombardment. The variation of pumping rate with the amount of hydrogen coming into the chamber causes some difficulty in calculating the penetration coefficient. In fact, in order to determine the penetration coefficient, we must know the pumping rate. But the pumping rate depends on the amount of hydrogen coming into the chamber, i.e., on the penetration coefficient. In view of this, the method of successive approximations was used for calculating T1, the zero approximation being a pumping rate of 10 dm3/sec. 116 Declassified and Approved For Release 2013/09/24: CIA-RDP10-02196R000700010002-5 Declassified and Approved For Release 2013/09/24: CIA-RDP10-02196R000700010002-5 The measured values of penetration coefficient for 1.0 35 keV, 1100 (current density 150 1jA/cm2) H1+ ions inci- dent on a stainless steel surface are shown as a function of the penetrated hydrogen?concentration in Fig. 5. Figure 4 (curve 3) shows the same results as a function of the amount of hy- 0,9 5 drogen entering the chamber. It should be noted that a large part of the curve falls in the region where the pumping rate is constant. Hence the penetration coefficient was here calcu- /0" 2 4 6 8 1018 8 1019 2 lated without correction for the hydrogen condensation pump N, particles/cm2 extraction rate. As we see from the curves in Fig. 5, as the density of penetrated atoms rises to N =1018 particles/cm2, Fig. 5. Variation of Ti with the number of particles the penetration coefficient falls from 0.96 to 0.93. As the penetrated per unit surface. concentration of penetrated atoms rises further, the penetra- tion coefficient remains constant right up to N=2 ? 1018 particles/cm2. We may well imagine that it continues steady to much larger concentrations. In addition to these measurements, we made some experiments to find the amount of penetrated hydrogen by weighing. This showed that the amount of such hydrogen reached 2 ? 1018 particles/cm2. These results of ours differ considerably from those of [2]. In [2], the penetration coefficient of D+ ions for a stainless steel target varied from 0.2 to 0.35 over the energy range 7 to 25 keV. In this range, target saturation oc- curred, as indicated by the equal flows of deuterium to and from the target. Thus, for example, for 15 keV D+ ions, saturation occurred for penetrated particle concentrations of 3 ? 1017 cm-2. The discrepancy between the results of [2] and our own can evidently not be ascribed either to differences in the masses or to differences in the energies of the penetrating particles. It would appear that the vacuum conditions, bearing on the state of the target surface, played some part in this. Although we did not make any specific experi- ments on the effect of the cleanliness of the target surface on the penetration coefficient, certain results indicated that the value of /I fell as the surface became less clean. In [2], the vacuum in the measuring chamber was 1.3 to 4 ? 10-8 N/m2, in which ?30% constituted impurities. This kind of vacuum is inadequate for maintaining the re- quired clean state of the target. For example, if the partial pressure of active impurities in the measuring chamber exceeds 10-1 Nirn2, then up to 0.1 monolayer may form on the target after heating it for 1 min. However, the dif- ferences in the state of the vacuum can hardly by itself explain the discrepancy between the results; there must be other sources of error in [2]. We have thus established that the coefficient of penetration of 35 kV Hi+ ions into a clean 1Kh18N9T stain- less steel surface exceeds 93%. This value of 71 remains unvarying right up to concentration of 2 ? 1018 cm-2 pene- trated atoms, and no sign of its further fall can be found. These results suggest that, under magnetic trap conditions, the extraction rate of slow neutral particles may be taken as at least an order less than the value determined by the rate at which fast particles pass out from a plas- ma region. LITERATURE CITED 1. L. J. Varnerin and J. H. Carmichael, J. Appl. Phys., 28, 913 (1957). 2. V. A. Simonov, Nuclear Synthesis. Part I [in Russian], Vena, MAGAT t (1962), p. 325. 3. J. Carmichael and E. Trendelenburg, J. Appl. Phys., 29, 1570 (1958). 4. J. Carmichael and P. Waters, J. Appl. Phys., 33, 1470 (1962). 5. E. Brown and J. H. Leck, Brit. J. Appl. Phys., 6, 161 (1955). 6. J. Koch, Nature, 161, 566 (1948). 7. K. Fiebiger, Z. angew. Phys., 9, 213 (1957). 8. E. S. Borovik, S. F. Grishin, and B. G. Lazarev, "Pribory i tekhnika eksperimenta," No. 1, 115 (1960). 9. E. S. Borovik, S. F. Grishin, and E. Ya. Grishina, ZhTF, 30, 539 (1960). 117 Declassified and Approved For Release 2013/09/24: CIA-RDP10-02196R000700010002-5 Declassified and Approved For Release 2013/09/24: CIA-RDP10-02196R000700010002-5 PERTURBATION OF PARTICLE MOTION IN THE STELLARATOR (UDC 533.9) A. P. Popryadukhin Translated from Atomnaya tnergiya, Vol. 18, No. 2, PP. 96-104, February, 1965 Original article submitted January 11, 1964, and in final form June 16, 1964 The conditions under which small perturbations do not disrupt the closed surfaces of trajectories of the guiding centers of charged particles in the stellarator are derived. It is shown in the linear approxima- tion that the toroidal stellarator with perturbations of the magnetic field constitutes an absolute trap for individual particles. It is well known that, in the drift approximation, the ideal stellarator constitutes an absolute trap for individ- ual charged particles. By "ideal stellarator" we mean a trap with a magnetic field possessing helical symmetry [H=-H(r, So?ctz)] and constituting the combination of a field created by helical conductors and a homogeneous field parallel to the z axis. The loss of particles through the ends in a system with finite length 27rR is eliminated, since the ends of the system coincide, i.e., the planes zo+ 27rRi=const (i= 0, 1, 2, ...) coincide and form a single plane. We shall call this the image plane. In an actual stellarator, there are different forms of perturbations to the particle motion: the toroidal aspect, imprecise construction of the magnetic system, currents in the plasma, and electric fields in the plasma. The effect of the toroidal aspect and magnetic field perturbations on the lines of force have been studied in a number of papers [1-6]. In this paper we shall consider typical effects of these perturbations on the motion of the particles. Motion of Particles in a Helical,Magnetic Field where Let us consider the motion of particles in an ideal stellarator field in the drift approximation. For static fields [7] mcvII et rot t) , dr ull [H if-c- rot vii dt 1/-1,2 Jill", v2 = v) r v2j_ = const, From Eq. (1) we obtain for the trajectory of the guiding center: where in the absence of current in the plasma To Eq. (3) we may add the relations 118 dr rdq dz 117! = = J_L = H = const, t = (1) (2) (3) H* H rot vilT. (4) dz dt v dt H = H* H ? (3a) Declassified and Approved For Release 2013/09/24: CIA-RDP10-02196R000700010002-5 Declassified and Approved For Release 2013/09/24: CIA-RDP10-02196R000700010002-5 In the case of helical symmetry, H=H(r, 0), 0 = co?az, and system (3) has the integral [71 r.r (a) uo = Al` -F aril; , 8 met;1 (5) 8 i 1 ' A*? A + eHl II, i I ___L -1? where A is the vector potential of the magnetic field. The trajectory of the I I guiding center of the particles lies on the surfaces 1 I 1 uo(r, 0) ---=.- C =- const, (6) slightly displaced from the magnetic surfaces determined from Eqs. (5) and (6) for m =0. Just as in the case of the magnetic surfaces, for the surfaces of tra- jectories of the guiding center there is a region bounded by a separatrix in which the surfaces are closed. It is this which determines the absoluteness of the trap. We write the second integral of system (3) in the form Fig. 1. Surface of guiding centers of blocked particles. de Z = C2. (7) The relation 0 = e (z) may be found from Eq. (7), but for transitory particles (v2?JiHmax> 0) it may be ob- tained by using the Aeraging method [8]. For one harmonic of the helical field I I nh,j(x) sin nO, n2 Hq) = (x) cos nO , Itz=110? nh,i17, (x) cos nO, where x=nar. For en= (hn/I-10)? 1 we may obtain where (1) =11)1-1- a?0*Z + En CD (x) sin n (1 ? az, n2 [ '19(I 2 ) (x)= ] , x x 171?y2 co* is the mean torsional angle of the trajectory, given by the formula aQ (1 v2 A "2 2 ) n2/2 \\ I + [ j-1 ( ) ] -x2x X ) yl_y2 X4 X2 aQ 3y4-12y2?81. 0)*= 17,441 ;,2 1/ x2 2/nrn + 2 X3 X2 n n x y2 4 (1? y2) Considering that the integrand in (7) is a periodic function, it is not difficult to obtain an exact expression for the torsional angle: (8) (9) 2zt C de 27i H*r? a (0)*-1) ? rH a* Declassified and Approved For Release 2013/09/24: CIA-RDP10-02196R000700010002-5 (9a) 119 Declassified and Approved For Release 2013/09/24: CIA-RDP10-02196R000700010002-5 For x ?1 expression (9) takes the form , n3 (n-1) etx2n-4 22n [(n_lp]2 yi -y2 = naQ (1-)1 (10) We note that in these formulas(1-y2)1/2 must betaken with the plus sign when the velocity v11 is directed along the field H and with the minus sign when v11 is opposite to H. Let us consider the motion of blocked particles. These will be particles the longitudinal velocity v11= (v2 -LH )1/2 of which may at certain points 01 become zero. At these points the particles will be reflected and vu will change sign. Since (5) is an integral of motion for all particles, including the blocked ones, they will move along surfaces r =r?(0) [see (6)], oscillating near the field minimum (Fig. 1). Drift of blocked particles will take place in the di- rection of the z-axis. In fact, from Eq. (7) we may obtain the increment Az after one reflection: 02 1. Az = r dO H;+ - - JIL .1 ? (P- 01 In expression (4), for 1-14, we take v11 with the plus sign and for H* with the minus sign; 01 and 02 are points of reflec- tion. With an accuracy of the first order in En we obtain aAz = 2n2a,o. -17-;22-814-1 [2E (k)? K (h)1, where E and K are complete elliptic integrals of argument k, and v2?-J "Ho J _LH oennl? k2 2f1lfog?ni? Analogously calculating the time required for the to-and-fro motion of the particles, we obtain an expression for the drift velocity 1 an3enmc v2 J Az 2 odr ?At - ell 2E (k)] x K (k) (12) We note that the direction of drift depends on the direction of H, the sign of the particle charge, and the sign of the expression 1-[2E(k)7/K(k). Calculation of Image Point Coordinates in the Presence of Perturbation Let H*= H*0+ 14*, where H*0 has helical symmetry and the perturbation is small. System (3) determines the characteristics for equation H*Vu = 0, (13) where u is an integral of system (3). Considering that u= un-U, in the linear approximation we obtain VO d-ri*Vuo= O. (13a) Since the first term of this expression is a derivative with respect to the direction of vector 1-16', we obtain a partic- ular solution for U: z dl? 11?*?1t9 dz H*0 ? 0 H z* ? zo (14) Integration is carried out over the unperturbed trajectory. This particular solution corresponds to the condition U =0 for z= zo. We note that Is a function of z and also of the coordinates of the initial poirl of the integration nl path U=U(z, C, 00, zo). Considering uo as a curvilinear coordinate, we may derive its variation under the influence of the perturbation in the length z-z0. Since u is an integral of (3), 120 Declassified and Approved For Release 2013/09/24: CIA-RDP10-02196R000700010002-5 Declassified and Approved For Release 2013/09/24: CIA-RDP10-02196R000700010002-5 u = ? L?/ (z, C, 00, zo) =C= const, we obtain from (14) z *Vo uo= C HuH.* dz. (15) zo z The correction `O. to 0 caused by the perturbation may be found from the relation w0(0, z)+ ?w (z, C, 00, zo)= C2 ; here w is determined by formula (14) if we replace uo by wo from (7). Carrying out the differentiation, we obtain w= ? 1-1; 0?arHzo Hz0) dz. (16) zo Let us now consider the intersection of the image plane by the trajectory of the guiding center. The coordi- nates of successive image points we obtain by substituting z =4+ 2nRi, 1=1, 2, . . . (17) into formulas (14) to (16) as upper limit of integration. Let us split the integral between the limits zo z :s zo + 27tRi into a sum of integrals between limits zo+ 27rR x (k-1):sz -z0+ 27rRk(k =1, 2, ... , i). It is easy to see that the in- tegrals obtained will differ only in the initial points of the integration path, coinciding with the successive unper- turbed image points (C, I). Introducing the notation we obtain for the i-th image point zo+2.7th u(0)=H*vuo dz, (4, z ? to ) o \ . It= kU (18) (19) With the help of Eq. (18) we may determine the change in the coordinate uo after one circuit as a function of e, i.e., u= u(e). Then Eq. (19) signifies that the increment in coordinate uo after i circuits equals the sum of the in- crements in the unperturbed image points. We can use the perturbation method on fulfillment of the conditions a ii*vu a l f ri*vuo) ? < 1, ( n 0 < 1. auo a* a0 H* The first inequality is fulfilled if, over the whole path of integration, the deviation from the unperturbed surface is small. Apart from this, however, over a long path of integration there may accumulate such a deviation in 0 from the true trajectory that the second inequality will not be satisfied. The convergence of the method may be improved if in formula (19) the value of 0 for the unperturbed image points e =el is replaced by 0 =0= 0+ 0. Then (19) takes the form k=1 Condition for the Existence of Continuous Surfaces for the Trajectories of Transitory Particles (19a) We shall suppose that the trajectory forms a closed continuous surface if the imaging points everywhere dense- ly fill up a closed curve on the image plane. Despite the fact that for a field with helical symmetry the drift equations have integral (5), describing closed surfaces uo(r, 0)=C, the trajectory of the guiding center of a particle may not form a continuous surface. This will 121 Declassified and Approved For Release 2013/09/24: CIA-RDP10-02196R000700010002-5 Declassified and Approved For Release 2013/09/24: CIA-RDP10-02196R000700010002-5 Fig, 2, Position of image points near resonance of the third kind, be so when the trajectory, after one or any finite number of passages around the sys- tem, closes upon itself. Here we obtain individual image points in the image plane. The condition under which the trajectory will have p image points may be obtained by equating the change in the angle after p circuits in formula (8) to a whole number of 27r. This condition, which we shall term resonance, has the form MCO* =11+ (20) where M=27rR/L is the number of periods of the helical winding in the length of the system. We see from this that, for the unperturbed trajectory to be described by a con- tinuous surface, Mw* must be an irrational number. In this way we shall have a se- quence of numbers of passages around the system pk-)..0 such that image points occur as near as we like to the initial point (C, en), i.e., for ph 0 ph, 00, and Taking account of Eqs. (19) and (21), we obtain (21) Ph urnE u (ei_,) 0. (22) Pk i=i bet us consider the meaning of Eq, (22) in more detail. Introducing the line density N(0)= pkn(e) of the image points on the curve uo(r, e), C, we rewrite condition (22) in the form ? Urnpa u (0i_i) n (0i_i) A0i =0, i=t where AO= ei, qk ei is the interval between neighboring points out of the Pk image points (Fig. 2), and Thus (22) is equivalent to the condition Y = (0) (0) dO =- O. U0-=7C An expression for 49i may be obtained from relations (7) and (94): (23) (22a) where 6 =Mw*-(vk)/pk (here vk/pk are proper fractions of the expansion of Mw* into an infinite continued frac- tion [9]). Since for almost all irrational numbers, except a set of degree zero, 6< (1)/p2k ln Pk and qk < pk, passing to the limit for pk-*-.0, we find From (14), (22a), and (24), we obtain 122 no (0) ? 1-6)* 27r H* ? 1? * arHz TI*VUO dl dcp 2m ji ( H*0 ,.,. arn z (24) Declassified and Approved For Release 2013/09/24: CIA-RDP10-02196R000700010002-5 Declassified and Approved For Release 2013/09/24: CIA-RDP10-02196R000700010002-5 Fig. 3. Resonance splitting of the surfaces. Thus The integration is carried out over the surface uo = C. Let us introduce as ele- ment of length ds along the curve u0= C, z= zo: ds =-- er dr +eq,rdp and calculate the element of area dS = dl x ds of the surface u0=C, where dl = d/ auo au , (erl-170+ e(pH0+ ezHo) H.o. Using the relation dr = / for z= zo Or o ay) and au? ip r au? ? ar11;!, alto = H*H-arn z ? ? ? r' -az aq, ar we obtain dS ? Vuo dl dq, aH*0 ( 1 II; arH: J = 1-:' uo=c (25) (26) Hence, in the presence of perturbation the surface u0 =C remains closed and continuous if the flux of the perturbing field H* through this surface is zero and condition (21) is satisfied. Resonance Action of Perturbations As already mentioned, when the resonance condition (20) is satisfied, the unperturbed trajectory of the parti- cle does not form a closed surface, but closes upon itself after a certain number of circuits p. Since w*= w' (u0), resonance of the p-th kind will be observed on the surface u0 =C, corresponding to condition (20). It is clear that, for, sufficient proximity to this surface and for sufficient smallness of the perturbation, the image points (uoi, 0i), where i=kp and k=0, 1, 2, ..., will be close to one another, so that by joining them we can obtain the approxi- mate form of the surface of trajectories (Fig. 3). According to formula (19), the increment in coordinate u0 after p circuits equals P P ? 1 au - /Lop 00_0 ItOph ==.- U i=t i (27) where 0_1 are the values of coordinate e corresponding to exact resonance. Let us calculate the increment 60 to the coordinate 0 after p circuits. If for the resonance surface Op(o_ 1)? Opk= 2rrni, where the whole number n1=Mp(1?wp*), for the surface uo =Cp+AC, close to the resonance surface Op (k?1) ?J)h= 2nn1 + 60 and according to (7) we may write Oph+2,rtn1+60 de 14* ') Ph (1 arH I 0=Cp+AC = ?2nMp. Expanding the integrand in the neighborhood of u0=Cp, replacing d/duil by (dw*)/duo ? (d)/dw, and taking account of (9a) and (24), for small 60 we obtain 60= MAC dcl)* ' AC = AC0+ u, n(0) duo where AC0 is the deviation of the unperturbed surface considered from resonance. Declassified and Approved For Release 2013/09/24: CIA-RDP10-02196R000700010002-5 (27a) 123 Declassified and Approved For Release 2013/09/24: CIA-RDP10-02196R000700010002-5 Fig. 4. Toroidal coordinate system. The condition of sufficient proximity to the resonance surface may be established with the aid of formulas (23) and (27). It is clear that the inequality 60?Aei (see Fig. 2) must be satisfied. Hence we obtain do)* M p2duo AC < 1. (28) If we take Mco*=Mw*+ 6 where co= co*(Cp), then 6 =Mdco*/duoAC0 and inequality (28) gives 1 - 6?>M dco/du0U, but at the same time conditions (28a) are satisfied. Equation (29) takes the form CU 1 73- u (0) no (0). The surface of trajectories is determined by the expression 0 u 0 (0) = C (A) no (0) de . eo (31) 00+2a r ? We see that the surface is closed if Y =u (0) no (0) d0 = 0. If however the integral Y 0, the surface winds .) 60 up (or unwinds) in a spiral, the pitch of which Au0=(1/6)Y(u0). Let us now consider the resonance case 6 =0. Since the differences in formula (28) are proportional to the perturbation, the second term in the numerator of the right hand side of Eq. (29) will be of a higher degree of smallness than the first. Neglecting this term, we obtain the equation after integrating which we shall have 124 dri ? p (0) nO (0) d0 PM duo u (0) = [ 24) k-p (0) no (0) de 1/2 . [PM W06-0 (32) (33) Declassified and Approved For Release 2013/09/24: CIA-RDP10-02196R000700010002-5 Declassified and Approved For Release 2013/09/24: CIA-RDP10-02196R000700010002-5 P Let us consider the properties of the function V(0) [see (30)]. By definition we see that Vp(0)= V p(e) for i= 1, 2, ... , since the trajectory emerging from initial point q forms the same p image points as the trajectory emerg- ing from 0. This indicates that the function Vp(0) takes the same values at the ends of the interval (ei, 0i+ q), where ei and Oi+ q are neighboring image points. Moreover, if condition (22a) is satisfied, 61+g p (0) O. ei In fact, as the coordinate 0 of the initial point varies over the range (00, 0q), the coordinates of successive image points will vary over (0i, 0i+ q) and i+g P r p (0) no (0) clO = ?u (A) no (0) dO = Y. ei i=t It follows from these two properties of function Vp(0) that it changes sign at least twice in each of the ranges (ei, ei+ q), passing through zero at the points denoted by ei and 0. Since at the points 01 and '02i the values of dVp/d0 have opposite signs, in each range (ei, ei+ q) Eq. (32) has at least one pair of singular points of the "saddle" and "center" type, so that the surface of trajectories of the guid- ing center in the case of resonance of the p-th kind acquires a rosette structure.with p-cells (see Fig. 3). The maxi- ' mum breadth of the i-th cell is determined by formula (33), in which the integration takes place over the range el to 02i. It is seen that this breadth is proportional to (H*)112 and (dw/du0)-112.1 In the absence of gradient the torsion- al angle dw/duo= 0 and the topology of the surface becomes unstable with respect to perturbations on satisfying the resonance condition (20).2 On satisfying condition (20) the rosette structure of the surface may also not be obtained if V(0).- 0. For the closed stellarator, every perturbation is periodic in z with period 2712. In the case of a perturbation of the magnetic surfaces (m=0), the perturbing magnetic field may be represented in the form H = v(I), where "1" = h" rink h#0 sin (lap + Tho) After substituting this expression into the formula 1 1 x l hi / Rik I/ sin iccp ? . . a, Irt:0 zo- p p "4? dz .112 ' Zo and carrying out some uncomplicated calculations for small 6, we find that V()) 0 0, if there is a harmonic of the field for which one of the following relations is satisfied3: _-4=O,ko (34) We note a peculiarity of the resonance action of perturbations on the trajectory of a particle. Since w* de- pends on the mass and velocity of the particle [see formulas (5) and (10)], for one and the same value of u0 and 6n =hn/Ho there may be resonance and nonresonance particles. Effect of Perturbations of the Magnetic Field and of the Toroidal State If the perturbation of the motion is connected with perturbations of the magnetic field H, then = nw l'An analogous result was obtained in [1]. rotH H ? rot, Ho 2This result agrees with the results of [4] obtained for magnetic surfaces. 3Relations (34) coincide with the resonance conditions obtained in [1]. Declassified and Approved For Release 2013/09/24: CIA-RDP10-02196R000700010002-5 (35) 125 Declassified and Approved For Release 2013/09/24: CIA-RDP10-02196R000700010002-5 V V2 ? J_LHO. Hence we see that div ft * =0, and from Eq. (26) it follows that Y=0. Thus, small perturbations of the magnetic field do not disrupt the closed nature of the trajectory surface:. Let us now consider toroidal perturbation. Let us introduce a coordinate system r, co, z. Here z will signify the arc length of the axial line of a torus with radius R; r and co will denote the distance to the axial line and the polar angle, respectively (Fig. 4). The metric tensor in these curvilinear coordinates has the form uth 1 0 0* .0 0 1 + ?11-.T COS (02 0 For R--0.3 the coordinate system so introduced passes over into a cylindrical system. It may be shown that in this case div H* In fact, div. H*=-6115-xl-T-P FikoH h . ail* h P riL,0.1/* 4- divo H*04-d iv ft.*+f LH*oi Hence div ft* = ?1hH0. Substituting the values of the Christoffel symbols rik, corresponding to the metric tensor gik, we obtain div IP= (HP cos tp ? M.1;0 sin (i)). Let us now check the equality of integral Y with zero [see (26)]: Y= I ace a d iv fi*dV. V. Going over to variables uo, 0, z, we find with the help of (25) and (36) 2rz C 2CH-2aR duo ? (u0, r (uo, 0) 23IM ?Hip (Ito, 0) ar (uo, 0) HI (110, 0) zo cos (0 + az) dz. Carrying out the integration over z and considering that ccR=M is a whole number, we convince ourselves that Y=0 and closed surfaces exist.' This constitutes a proof of the idealness of the toroidal stellarator as a trap ihthe,drift approximation for transitory particles.2 Action of the Perturbation on the Blocked Particles Making use of expression (14), we obtain the change in the coordinate uo after reflection of the particle: d ?'2 ?*Vu 1-1'17u0 Au H ? di +S101 H*0 so2 Oriy The integration is carried out along theunperturbed trajectory corresponding to the to-and-fro motion between the reflection points 01, 02; these trajectories lie on the surfaces S1 and S2 determined from (5) and distinguished by the sign of v11. 'In [4] the necessity of satisfying condition div 11*= 0 for closed surfaces to exist is indicated, but, despite the"fact----: that this condition is not fulfilled, closed surfaces here exist, since Y = 0. 2In [10] the proof of this fact is given on the approximation of the conservation of the longitudinal invariant. 126 Declassified and Approved For Release 2013/09/24 : CIA-RDP10-02196R000700010002-5 Declassified and Approved For Release 2013/09/24: CIA-RDP10-02196R000700010002-5 As was seen in the first section, the blocked particles drifting along the z axis pass around the system. Let us denote the change in coordinate uo after a complete circuit by Y1. Then the condition for the closed state of the surface of trajectories of the blocked particles will clearly have the form Y1=0. Let us consider the expression ds x dl, where ds= (are, + ez)dz is the element of length of the line (p ?az= const; r = const. Using relation (25), it is not hard to confirm that Thus dz dl ds x dl Vuo H*9 ? Yi ? ( rrds) , Az where dS = ds x dl and the direction of the normal to surface S2 is opposite to Vuo. If rrdoes not depend on v11, then Yi * dS = yi,z div ii* dV. v The integration is taken over the region enclosed between surfaces SI. and S2. In the case of perturbation of the magnetic field, we obtain with the aid of formula (35) 1me Uri MC " 11 Az Y i = div ii dV + me c rot ?vil H dS -- rot- eAz li rot ?1-- Ho dS -1-- H dS Ho V Si SiSi ' eAz mevo - rot II Ho dS ? 2me V 'II ? e dr ? --- Ho dr . eAz /JO eAz H1-1 2in c Az . S2 ? (38) The boundaries of the ranges of integration on the surfaces SI, S2 and Si', S2' are defined as the reflection points of the particles (S1,2 and S1,2' do not quite coincide owing to the effect of the perturbation on the reflection points). On the contours C and C' embracing S1,2 and S1,2', we have everywhere v11= 0, so that Y1=0. In the case of the toroidal state, the proof that the term containing div 1-1* is zero is analogous to that derived for the transitory particles. Thus, in the drift approximation it is proven that for small perturbations of the magnetic field the toroidal stellarator remains an absolute trap for individual charged particles. We must comment on the group of resonance blocked particles for which Az = 0. Resonance particles are those having such values of vi/v that in formula (11) 2E(k)?K(k)= 0. For these particles the deviation from the unper- turbed surfaces in the linear approximation is unlimitedly large.1 Thus the essential condition which the perturbing vector field ji* must obey so as not to disrupt the closed surface of trajectories of the guiding center of the Earticles lies in the requirement that Y=0. This condition is satisfied if div 0. Perturbations for which div H* 0 are to be suspected. An example of such perturbation is the ?toroidalness,? but as we saw the condition Y= 0 is satisfied for toroidal perturbation. Yet another example of perturbation with div 11* 0 is the perturbation of the magnetic field by plasma currents. In this case, as seen from Eq. (1), div 43-cent ?divv11 ? H2 OH) We may mention a perturbation for which, apparently, Y this is the slow variation of the magnetic field with t time (the field was considered constant). 1The existence of resonance blocked particles was noted in [10]. 127 Declassified and Approved For Release 2013/09/24: CIA-RDP10-02196R000700010002-5 Declassified and Approved For Release 2013/09/24: CIA-RDP10-02196R000700010002-5 It is also necessary to check perturbation of the motion by the electric field. LITERATURE CITED? 1. L. M. Kovrizhnykh, "Zh.' tekhn. fiz.," 32, S17; 526 (1962). 2. L. V. Kbrablev, A. I. Morozov,' and L. S. SOlov'ev, 'Mid, 31, 10, 1153 (1961); 3. I. M. Gel'fand et al., Ibid, 31, 1164 (1961). 4. G. V. Skornyakov, Ibid., 32, 261; 777; 1494 (1962). 5. L. M. Kovrizhnykh, Ibid., 33, 377 (1963). 6. I. M. Gel'fand et al., "Dokl. AN SSSR," 148, 1286 (1963); 143, 81 (1962). 7. A. I. Morozov and L. S. Solov'ev, "Dokl. AN SSSR;" 128, 3 (1959). 8. N. N. Bogolyubov and Yu. A. Mitropol'skii, Asymptotic Methods in the Theory of Nonlinear Oscillations [in Russian], Gostekhteorizdat, Moscow (1955). 9. A. Ya. Khinchin, Proper Fractions [in Russian], Gostekhteorizdat,,Moscow (1961). 10. A. I. Morozov and L. S. Solov'ev, "Zh. tekhn. fiz.," 30, 261 (1960). 128 Declassified and Approved For Release 2013/09/24: CIA-RDP10-02196R000700010002-5 Declassified and Approved For Release 2013/09/24: CIA-RDP10-02196R000700010002-5 EXPERIMENTS ON THE BUILDUP OF ELECTRONS IN THE SYNCHROTRON (UDC 621.384.612) Yu. M. Ado, E. G. Bessonov, and P. A. Cherenkov Translated from Atomnaya Energiya, Vol. 18, No. 2, 1 ? pp. 104-107, February, 1965 Original article submitted February 24, 1964 The lifetime of electrons in the synchrotron-accumulator was determined experimentally as a func- tion of residual gas pressure, accelerating voltage, and particle energy. The experiments were car- ried out in the 280-MeV synchrotron of the Institute of Physics, Academy of Sciences of the USSR, operating in the accumulator condition. It was found that, for small buildup densities, the lifetime of the particles was mainly governed by single events of electron scattering by residual gas atoms. The possibility of accumulating electrons in the synchrotron by the method proposed in [2] was experimen- tally verified in [1]. We here present experimental results bearing on the effects of various factors on the lifetime of the particles. The work was carried out in the 280-MeV synchrotron of the Institute of Physics, Academy of Sci- ences of the USSR [3]. A description of the experimental methods and apparatus may be.found in [1]. The number of particles in orbit was measured from the intensity of the synchrotron radiation and recorded on a loop oscillograph. Figure 1 shows one of the oscillograms of the buildup process. The buildup takes place on the rising part of the oscillogram. The falling part characterizes the particle lifetime (microtron switched off). As particle lifetime we take the value of r for which exp [?t/r] coincides with the envelope of the falling part of the oscillogram. The variation of r with the following factors was determined: 1) Amplitude of the high-frequency ac- celerating voltage V; 2) vacuum p; 3) particle energy; 4) peak modulation depth of the high-frequency accelerating voltage AV/V [1, 2]. In the graphs presented, r is measured either in periods of the variable component of the guid- ing magnetic field of the synchrotron or else in seconds. When the synchrotron is operating in the accumulator condition, the particle energy varies according to E E,+ E cos 23t Tt (1) The particles are periodically accelerated to a maximum energy Emax= E=+ E0 and retarded to a minimum energy Emin=E=?E0. The frequency of the variable component of energy is 1/T =50 cps. 1. Variation of T with V. The following quantities were kept constant: Emax = 180 MeV, Emin= 7.5 MeV, AV/V=0.2, p ? 10-6 torr. The amplitude of the accelerating voltage was varied from 1.5 to 1.0 kV. The relationship found appears in Fig. 2. 2. Variation of T with Vacuum . This was obtained for the following conditions: Emin =7.5 MeV, Emax = 180 MeV, V=1.5 kV, AV/V =0.2. The vacuum chamber was evacuated with two units operating from dia- metrically opposite sides. A change in vacuum was ef- fected by shutting off one of these. It turned out that on varying the vacuum by a factor of two r also changed by the same factor. Fig. 1. Oscillogram of the particle buildup process. 3. Variation of T with Particle Energy. In these experiments the following were the constant quantities: E= = 94 MeV, V=1.5 kV, AV/V = 0.2, 3 ? 10-6 torr. The particle energy was varied by changing the amplitude of the variable component Eo. Particle 129 Declassified and Approved For Release 2013/09/24: CIA-RDP10-02196R000700010002-5 Declassified and Approved For Release 2013/09/24: CIA-RDP10-02196R000700010002-5 70 60 -o 50 40 30 1000 TWO 1000 1300 1400 V, V Fig. 2. Variation of T with accelerating voltage V. C, sec 0 10 20 Emin, MeV E0, MeV 84 74 64 Fig. 4. Variation of T with the ampli- tude of the variable component of par- ticle energy E0'. Continuous curve con- structed from formula (2) relative to the experimental value of T for E0' = 86 MeV. Measurement of r Fig. 3. Illustration of the reduction in amplitude of the variable component of particle energy E0 to E0' when measuring the variation of r with E0'. buildup was effected for Emin= 7.5 MeV. After reaching the limiting number of particles, the value of to was rapidly reduced to some value E0' (Fig. 3). Injection of particles thereupon ceased. After the establishment of E0', the par- ticle lifetime was measured. The results of measuring r for various E0' (or for various Emin, which comes to the same thing) are shown in Fig. 4 by points. In absolute magnitude the calculated values of r exceed the experimental. This is evidently connected with imprecision in measuring the vacuum. 4. Variation of T with AV/V. The follow- ing were kept constant: Emin =7.5 MeV, Emax= 180 MeV, p 3 ? 10-6 torr, V=1.5 kV. The value of V/V was varied from 0 to 0.6. The relationship obtained is shown in Fig. 5. After absolute calibration of the particle recording system, the number of accumulated electrons N was also determined from the intensity of the synchrotron-radiation. It was found that N 5 ? 108 for r =1.7 sec, microtron pulse current mA, AV/V=0.2, and growth rate of guiding magnetic field at moment of injection 3 ? 105 0e/sec. As in [1], in place of an inflector system we used a 0.2 mm thick tantalum electron scatterer. The particle loss mechanism in an accumulator with variable guiding field has a certain peculiarity. Parti- cles whose oscillation amplitude has increased cannot be lost at once, but only when the energy is reduced as a result of an adiabatic increase in the oscillation amplitude. To the single processes affecting T belong Coulomb scattering and bremsstrahlung of particles at residual gas atoms. It may be shown that the partial lifetime determined by the Coulomb scattering of particles in the variable energy accumulator is expressed by the formula OV min OM min+ V2 min P 41c71,?21V oc 7 (2) where re = e2/mc2 is the classical radius of the electron, for air z-= 7.2, the number of residual gas atoms per cm3 N0=7.12 ? 1015 p torr, 0g is the permissible scattering angle for minimum energy, and y =E/m0c2. For an elliptical cross section of the vacuum chamber with semiaxes rk and zk, the value of 0 is determined by the expression 02g ? 1. 1 812 711 ' ( ? where Xr and Xz are the wavelengths of the radial and axial free oscillations of the particles. The partial lifetime for the bremsstrahlung process is practically independent of particle energy, being [4] 1.92.1013 130 No (3) (4) Declassified and Approved For Release 2013/09/24: CIA-RDP10-02196R000700010002-5 Declassified and Approved For Release 2013/09/24: CIA-RDP10-02196R000700010002-5 70 Also contributing to particle losses are multiple processes such 60 -0 as quantum fluctuations of the synchrotron radiation and multiple ), scattering by residual gas atoms. Since the dimensions of the sepa- ratrix are always considerably smaller than the radial dimensions of 750 the vacuum chamber cross section, the particle loss will be deter- mined by the setting up of phase oscillations, i.e., in practice by the action of quantum fluctuations [4]. Qualitatively the particle 30 loss mechanism may be represented in the following fashion. Let 0 Cl 02 03 0.4 0.5 0.6 AO us separate out an imaginary trajectory which, for particle energies E :0.-.Emin, "coincides" with the separatrix in the phase plane. For Fig. 5. Variation of T with modulation depth E>Emin the selected trajectory is inside the stable region. Then of accelerating voltage AV/V. all the particles which, under the action of the quantum fluctuations, have passed out beyong the limits of this phase trajectory will be lost on subsequent reduction of the energy to -Emin. Here the quantum fluctuations will play a more significant part than in constant magnetic field accumulators. In order to find an expression for the probability of particle loss in our case, we must solve the Einstein-Fokker equation [5] for the particle distribution function U applicable to a variable guiding magnetic field: au at dt Ou Cu ' = cht a [ au u --L 1t2 (t) UU 1 , , (5) where u is the square of the true oscillation amplitude, and d ln D2 dET 55n ceA dt 12 173 (1---n)R4V sin (Ps , , 6 x2 (t) dt du dt - 0.5 Here D2 =e-2j Cdt (y V sin (Ps) describes the adiabatic variation in the amplitude of the phase oscillations and the radiation damping with decrement t. The solution of Eq. (5) for zero conditions at infinity is where Q 2(0 obeys the equation 1 Uju, et/12(l), Q2 (t) , 2 d ln dt (6) (7) For steady dimensions of the particle beam, Q(t+T)= Q(t). Moreover the periodic solution of Eq. (7) has the form D2 (t) D2 (t Q2 (t)? Dz (t)_- D2 (t T) t+T d-u , D-2 (t, ) dt, dt. (8) We can determine the particle loss in each period of the magnetic field after integrating distribution (6) over thrt limits uex to .0. Then the partial lifetime of the particles due to the setting up of phase oscillations by quan- tum fluctuations of radiation will equal T q --= T eu ex/P2 Te, since Q-2- V, as di/dt-.V'. The factor a depends only slightly on V. The ratio uex/Q2 must be taken for E>>Emin, when the distribution (6) is practically contained in the region of linear phase oscillations. The quantity Q2 can be calculated from formula (8), and uex determined by the method of adiabatic invariants, starting from the uex for E Let us compare the partial lifetimes Tp, TT and Tq for a chosen condition of synchrotron accumulation (see relationships 1 to 4). The radius of the synchrotron orbit R= 81 cm, the free space of the vacuum chamber rkzk 4 X 4 cm, and n= 0.6. From formulas (2) and (4) it is easy to find that in this case TT lip = 23, i.e., the bremsstrahlung (9) 131 Declassified and Approved For Release 2013/09/24: CIA-RDP10-02196R000700010002-5 Declassified and Approved For Release 2013/09/24: CIA-RDP10-02196R000700010002-5 acts considerably more weakly on the particle lifetime than Coulomb scattering. The quantum fluctuations of the synchrotron radiation markedly affect the particle lifetime, as seen in Figs. 2 and 5 (T depends on V and AV/V). It is difficult to determine T and T from formulas (2) and (9), since the quantities p, V, E0, and E., are not known accurately enough. It is however possible to estimate the contribution of the quantum fluctuations and Coulomb scattering to the particle loss on the basis of the experimental relation between I and V. It follows from Fig. 2 that, for V=1 kV, r= O.8 sec; for V=1.5 kV, T2=1.2 sec. Using the difference (1/T1)?(1/T2), formula (9) shows us that 4.8. Substituting this value of a into formula (9), we find Tql= 2:4 sec (V=1 kV), and Tq2 = 26 sec (V=1.5 kV). From the condition 1/11.2= (lfrp)+ (1/Tq12) we obtain Tp 1.2 sec. Hence we may consider that, for V=1.5 kV, T is completely determined by the Coulomb scattering. This is also indicated by 'relationship 2 and the agreement between the T/particle energy relations as found by experiment and calculated from formula (2) (see Fig. 4). With- out discussing the relation between T and AV/V in detail, we can only say that the introduction of amplitude modu- la.tion has a weak effect on T. In conclusion we note that, on improving the vacuum, the role of quantum fluctuations of the radiation will increase. The particle loss may however be substantially reduced if V is increased. For example, from fromula, (9) with a =4.8, the value of Tq proves to be of the order of a few hours with V=2.5+ 3 kV. LITERATURE CITED 1. Yu. M. Ado et al., Transactions of the International Conference on Accelerators [in Russian], Atomizdat, Moscow (1964), P. 355. 2. Yu. M. Ado, "Atomnaya energiya," 12, 54 (1962). 3. A. Ya. Belyak et al., In the collection "Elementary Particle Accelerators" [in Russian], Supplement No. 4 to "Atomnaya energiya" for 1957, Atomizdat, Moscow (1957), p. 57. 4. A. I. Alikhanyan, S. A. Kheifets, and S. K. Esin, "Uspekhi fiz. nauk," 81, 7 (1963). 5. A. A. Kolomenskii and A. N. Lebedev, Theory of Cyclical Accelerators [in Russian], Fizmatgiz, Moscow (1962). 132 Declassified and Approved For Release 2013/09/24: CIA-RDP10-02196R000700010002-5 Declassified and Approved For Release 2013/09/24: CIA-RDP10-02196R000700010002-5 ANGULAR AND ENERGY CHARACTERISTICS OF THE NEUTRONS EMITTED IN U235 FISSION (UDC 539.173.84) M. V. Blinov, N. M. Kazarinov, and A. N Protopopov Translated from Atomnaya Energiya, Vol. 18, No. 2, pp. 108 -113, February, 1965 Original article submitted January 13, 1964; revision submitted March 3, 1964 The velocities of a fission fragment and of a neutron moving in the same direction were measured simultaneously by the time of flight method for the thermal neutron fission of U235. As a result, the emission spectrum of the fission neutrons was obtained. The angular distributions and energy spec- tra were also measured for the neutrons ejected at different angles to the direction of motion of the fission fragments. These distributions were compared with calculations in which the emission spec- trum obtained was used. The comparison showed that the data agree well after excluding small de- viations in the angular distribution. It follows from analysis of the results that the emission spec- trum agrees with the data calculated by the statistical theory of evaporation and also that not less than 90% of the neutrons from U235 fission are emitted in the process of isotropic evaporation of neutrons from the completely accelerated fission fragments. The energy spectra and angular distribution of neutrons emitted in the thermal and fast neutron fission of U235 were measured in [1-3]. The measurements were carried out for angles of flight of 0, 45, and 90? of the neutrons re- lative to the direction of motion of the fission fragments. It can be seen from the experimental data that in accor- dance with the hypothesis concerning the emission of neutrons by the moving fission fragments, the neutron spectrum is strongly dependent on the angle of flight. In addition, some information was obtained in these experiments con- cerning the neutron spectrum in the center of mass system. The results of the experiments show the desirability for additional experiments on the mechanism of fission neutron emission. The velocities of a fission fragment and of a neutron emitted by this fission fragment in the direction of mo - don were measured. As a result of the measurements, the neutron emission spectrum was obtained (the spectrum in the center of mass system). Similar measurements were also made of the angular and energy distributions of the neutrons, independently of the type of fission fragment as well as individually for light and heavy fission fragments. The emission spectrum of the neutrons obtained experimentally was used in the spectral and angular distribution calculations. Measurement Procedure Figure 1 shows the arrangement of the experiment by means of which the neutron and fission fragment velo- cities were measured simultaneously by the time of flight method. The uranium target, with a thickness of 100 1ig/cm2 and containing 97.9% of U235 on a thin organic film, was placed in a thin-walled aluminum tube (length 75 cm, dia- meter 10 cm) which was pumped out to a pressure of ? 10-3 mm Hg. The fissile layer was located at a distance of 1.5 cm from the rim of the tube, where a fission detector was installed?a scintillation film with a diameter of 20 mm in a plastic light guide and connected to a transient photomultiplier. "Zero time was defined with respect to the instant of impact of a fission fragment on this scintillation film. An additional fragment traversed the entire length of the tube and was recorded by another film detector with a diameter of 80 mm. A correction was intro- duced for the spread of the time of flight of the fission fragments from the layer to the "zero time" detector. The neutron counter was located at an angle of 15? to the tube axis at a distance of 65 cm from the uranium target. In order to record the neutrons, a stilbene crystal was used with a diameter of 80 mm and a thickness of 40 mm and also an FEU-33 transient photomultiplier. 133 Declassified and Approved For Release 2013/09/24: CIA-RDP10-02196R000700010002-5 Declassified and Approved For Release 2013/09/24: CIA-RDP10-02196R000700010002-5 Neutron beam u35 Vacuum pump CF PM PM CF 3 4 5 Fig. 1. Diagram of the arrangement for simultaneous measurement of the velocities of a fission fragment and of a neutron, and block diagram of the apparatus: 1) scintillation films; 2) stilbene crystal; CP) cathode followers; 3) time converters; DI, D2, D3) amplitude discriminators; 4) two-dimensional analyzer; 5) transmission block; 6) coincidence circuit. Two "time into amplitude" converters were used in the equipment: one for measuring the velocity of the fis- sion fragment and the other for measuring the neutron velocity. The pulses from the converters were fed to a two- dimensional analyzer. The characteristics of the time of flight spectrometer used in this project are described in the literature [4]. In the present measurements, the effect of the photomultiplier signal amplitude on the time scale calibration was additionally taken into account which increased the accuracy in determining the neutron energy. The recording efficiency for neutrons with different energies was determined experimentally by means of calibration measurements of the well-known fission neutron spectrum of U235, averaged in the experiment with respect to all-fis- sion modes and all angles of flight of the neutrons. The experimental data agreed well with the calculations of the efficiency. The resolving time for recording fission fragment coincidences, measured by means of a chamber in which fission fragment detectors converge up to 2 cm, was found to be equal to 2.5 nsec. The distribution half- width of the prompt y-radiation, emitted as a result of fission, corresponded to a resolving time for the neutron chan- nel of 4 -5.tiseo. In the second part of the project, the angular distributions and energy spectra of the neutrons emitted at differ- ent angles to the direction of motion of the fission fragments were measured. For this, the device described in [3] was used; in it the U235 fission fragments were recorded in a gas scintillation counter. In order to fix the direction of motion of the fragments, a collimator was located at the uranium layer with a thickness of 2 mg/cm2, in which the mean angle of deviation from the normal of the fission fragments was 100. By installing thin layers (? 200 1g/cm2) of uranium in the gas counter, it became possible to separate the fission fragments into two groups?a light and a heavy group, and the neutron spectra are associated with these groups. The neutron scintillation counter was located at a distance of 65 cm from the fissile layer at various angles to the direction of flight of the fission fragments (0, 15, 30, 45, 60, 75, and 90?). In order to record the neutrons, a thin crystal of stilbene was used (with a diameter of 30 mm and thickness 15 mm) as well as the crystal with a dia- meter of 80 mm and thickness 40 mm. Measurements and Results In all the experiments for measuring the neutron characteristics by the time of flight method, it was assumed that over the time interval 10-100 nsec there are no delayed 7-rays from fission. If the contrary were the case, this would change the experimental results of measurement of the neutron spectrum as well as their number. The rela- tionship between the number and energy of the delayed y-quanta and the delay time for 50 nsec to 10-5 sec was mea- sured in [5] with equipment having a resolving time of 2.10-8 sec. It was found that over this interval, 5.7% of the 134 Declassified and Approved For Release 2013/09/24: CIA-RDP10-02196R000700010002-5 Declassified and Approved For Release 2013/09/24: CIA-RDP10-02196R000700010002-5 Number of neutrons, relative units 0 ZO 10 4 En, MeV Fig. 2, Neutrum spectrum in the center of mass system measured at an angle of 15? to the direc- tion of motion of light (0) and heavy (x) fission fragments in the laboratory system of coordinates. The continuous line indicates the spectrum used in calculating the neutron spectra and intensities at various angles. total number of "prompt" quanta is emitted as delayed y-quanta. In view of the poor resolution and the large range being mea- sured, the interval of time prior to 100 nsec has been inade- quately studied. We measured the number of delayed y -quanta over the interval 25-80 nsec. For this the neutron counter was located at a distance of 350 cm from the uranium target. Neutrons, on this base line, were almost eliminated from the range of the times of flight being determined. No delayed y-quanta were re- corded within the limits of experimental accuracy. This con- firms that even in the case of equilibrium distribution of these Huanta, with respect to time their number does not exceed 2% of the total number of "prompt" y-quanta. Thus, within the stated range of times of flight the delayed y-quanta, obviously cannot have any significant effect on the determination of the fission neutron spectra. In the course of the project, measurements were made in which the corrections for scattering of neutrons from the backing and from the collimator in the gas counter were determined, and also for scattering from the shielding. The corrections were introduced into the data for the number as well as for the spec- trum of the neutrons. In the case of measurements of the two velocities, about 15,000 pulses from fission neutrons were col- lected. For the measurements made at an angle of 0?, 50 ? 103 neutrons were recorded and two to three times less for measure- ments at the other angles. The random coincidence background was the same as stated in [3]. Figure 2 shows the neutron spectrum in the center of mass system which was determined from the simultaneous measure- ments of the velocity of a neutron and of a fission fragment. The neutron velocity in the center of mass system was calculated by the formula 2 2 /16 2 -1- v - 21;V0 cos y. Here v, v0 and ip are the neutron velocity, the fragment velocity and the angle between the directions of motion of the fragment and neutron in the laboratory system of coordinates respectively. The angle cp was chosen to be the least possible (15?) in order that the neutron contribution from any additional fission fragment would be small. The The average energy of the emission spectrum was T= 1.27 ? 0.03 MeV and it can be represented numerically by die superposition of three distributions F (e) 17i TY2 where T1 = 1 MeV, al = 0.696; T2 = 0.5 MeV, a2 = 0.310; T3 = 0.1 MeV, a3 = ?0.06. It should be noted that the spectra of the neutrons emitted by light and heavy fission fragments agree within the limits of experimental accuracy (Tr-ih < 0.02 MeV). The energy spectra of the fission neutrons are shown in Fig. 3 for various angles. For simplicity of comparison of the spectral shifts the maximum probability is reduced to a uniform value for all values of the angles. The rela - tionship between the relative intensity of the fission neutrons and their average energies, and the angle (,o for two cases?the registration of all fission fragments and individually for the light fragmentsl ?is shown in Fig. 4. It can be 1The data refer to the neutron energy region of 0-7 MeV. For energies from 0.3 MeV and above the experimental data are used ,and for energies below 0.3 MeV these data are used extrapolated to zero. The error of this extrapolation is small. The distributions for angles 0,45 and 90? are in good agreement with the results of our measurements carried out previously [3]. 135 Declassified and Approved For Release 2013/09/24: CIA-RDP10-02196R000700010002-5 Declassified and Approved For Release 2013/09/24: CIA-RDP10-02196R000700010002-5 0 V, iii. v4..'? , \ r =15 0?0 1 ---30? 2: \V1W 750 90? WitiSi -'4i1\114..14 2 4 5 6 En, MeV Fig. 3. Energy spectra of neutrons emitted at varous angles co to the direction of motion of the fission fragments. 0,5 30 60 90 120 co, degrees Fig. 4. Relationship between relative fission neutron intensity W and their average ener- gies V, and the angle of flight cp.- all fragments recorded; ----only light frag- ments recorded. seen that with increase of angle from 0 to 900 and with simultaneous reduction of intensity, a systematic "softening" of the spectra occurs. Qualitatively this is in accordance with the hypothesis of the ejec- tion of neutrons from moving fission fragments. Discussion of Results Using the neutron emission spectrum obtained for 9 = 150, the spectra can be calculated in the laboratory system for the various angles and they can be compared with the experimental energy dis- tributions. This calculation was performed on the assumption that the neutron distribution in the center of mass system is isotropic. Instead of the distribution of the fission fragments with respect to velocity, the mean velocities of the light and heavy groups were used. The energy distribution of the fission neutrons emitted at an angle co to the direction of flight of the light fragments is given by the ex- pression (see for example [6]): (I) ? N (E) dE 1 F ' (e) P (T) dq) dE vT 180? ? cp2 eF" (8) P (cp) dcp dE . 180*-1:P1 Here, E and e are the neutron energies in the laboratory and center of mass systems respectively; F'(e) and F"(e) are the emission spectra of the neutrons emitted by light and heavy fragments respectively; P(9) is the distribution with respect to angle of the fission fragments traversing the collimator. The second term of the expression corre- sponds. to the emission of neutrons in the rear hemisphere from an addi - tional fragment. The ratio Vi/Vh, equal to 1.10, was used. for the calculation and satisfied the experimental data best. Figure 5 shows the ratios of the experimental and calculated values for the average energies and intensities of the nuetrons versus the angle 9, and Fig. 6 shows the ratios of the probabilities for individual parts of the spectra and for various values of 9. The errors in Figs. 5 and 6 include the statistical error as well as the deviation between 136 Declassified and Approved For Release 2013/09/24: CIA-RDP10-02196R000700010002-5 Declassified and Approved For Release 2013/09/24: CIA-RDP10-02196R000700010002-5 Eexpt. Ecalc 1.0 0.9 Wexp t. Walc 1.1 1,0 0.9 I a 1.1 1.0 0.9 Li 1.0 0.9 4- 30 50 .90 0 yo, degrees ? a rH 60 10 th0 Fig. 5. Experimental and calculated values Texpt/Ecaic (a) and Wexpt/Wcalc (b) as a function of neutron angle of flight (c and d are the corresponding values for recording only the light fission fragment). Wexpt- (E) Wcalc. (E) 1.0 0.9 1.1 1,0 0.9 I.1 1.0 0,9 1,1 0.9 1,0 1,1 1,0 0,9 1,1 i.0 0,9 1,1 yo,degrees ? ? 0 -. 15 4 - -f- fr. f ? ? , ? ? ? ? 30 45 60 75 90 . 0(L) 0(H) ? 30(L) 30(H) 0 1 2 3 4 5 En, MeV Fig. 6. Ratio of experimental and calculated probabilities Wexpt/Wcalc ' for various parts of the energy spectra and angles of flight (p. The data are normalized for maximum probabilities of the spectra. series. It can be seen that not only the average energies of the experimental spectra agree satisfactorily with the calculation, but also their shape as a result of changing the spectral intensity by a factor of more than 10. It is possi- ble that there is a small increase of "hardness" of the spectrum relative to calculation at angles close to 900, al- though it is found to be within the limits of experimental error. A larger relative intensity can be noticed in the angles of distribution for angles of 60 and 900 and, thus, a less anisotropic distribution in the laboratory system com- pared with calculation. 137 Declassified and Approved For Release 2013/09/24: CIA-RDP10-02196R000700010002-5 Declassified and Approved For Release 2013/09/24: CIA-RDP10-02196R000700010002-5 An estimate of the effect of velocity distribution of the fission fragments and the dependence of D-(A) on the results of the calculation with respect to angular distribution showed that the error associated with this does not ex - ceed a few percent and thus cannot exert a significant effect. An attempt was made to completely reconcile the experimental and calculated data on the assumption that the neutrons are emitted by fission fragments having partial velocities. As a result of this the angular distributions are successfully reconciled, but the calculated spectra in this case differ considerably, from the experimental spectra. If it be assumed, as a consequence of [7], that emission of neutrons is possible at the instant of separation of the fission fragments, and if the deviation of Wexpt/Wcaic at an angle of 90? be associated with this assumption, then the number of such neutrons in the case of isotropic emission in the laboratory system should not exceed 5-10% of the total number of neutrons. Yet another reason can be proposed for the appearance of excess neutrons at an angle of 90?. If part of the neutrons is "evaporated" from a fission fragment prior to the establishment of thermal equilibrium by the entire volume of the nucleus, then it is possible that these neutrons are "evaporated" mainly from a local region where the nucleons of the offshoot are situated (the part of the neck joining the fission fragments prior to separation). Ejection of neutrons from this region at small angles to the direction of motion of the fission fragments is unlikely (because of shielding by the mass of the nucleus); thus, a "shadow effect" is created. This same effect, obviously, should be observed also in the case of neutron emission from the neck region prior to or at the instant of separation. The spectrum, in the center of mass system, which agrees with our experimental data has an average energy 7 equal to 1.27 MeV, which is somewhat greater than the value obtained in [8] on the basis of scaling the integral spectra (T= 1.21 MeV). Here, it is necessary to consider that the deviations at an angle of 60-90? are related to an addition in the low-energy part of the integral spectrum and thus .soften it. In order to compute whether the spec- trum in the center of mass system has a cascade-evaporative nature it is necessary to take into account in the first instance the energy spread of the excited fission fragments with respect to mass and charge, the relationship between the level density and the characteristics of the fragment and its excitation energy. Over the whole volume this is quite a difficult problem and it has not been considered in this paper. Simplified calculations have been carried out for computing the emission spectrum, in which the change of temperature due to the different excitation energies of the fission fragments and the subsequent emission of neutrons were taken into account. The first calculations,.car- ried out in a similar paper [9], gave as a result a spectrum close to the experimental spectrum but somewhat dis- placed to the side of low energies (T= 1.22 MeV). In the second stage of the calculations, for cases of large frag- ment excitation, when emission of more than one neutron is possible we took account of the relationship obtained in [10] for cascade evaporation of the neutrons. It was found that this calculated spectrum for a = 12 MeV-1 agrees well with the experimental spectrum. Thus, it can be said that despite the small deviations from the calculation, which may be explained by a variety of reasons, the overwhelming portion of the neutrons from the thermal fission of U235 is emitted in the process of normal cascade evaporation of neutrons from the completely accelerated nuclei-fission fragments. It is noteworthy that the emission spectra of the neutrons from light and heavy fission fragments are identical. If the average value of the neutron binding energy is used for the light and heavy fragments, the quantity -17//17h set equal to 1.1, and the relationship T cs:)(Eb/a)1/2, then it is found that the average energy of the emission spectrum for a light fission fragment should be considerably greater than for a heavy fission fragment (by ? 30%). However, the action of shell effects leads to approximate equivalence of the level plane constants, a, for the region of light and heavy fragment masses (in view of the inadequacy of the information in [11, 12] it is difficult to obtain more precise data). The cited effects also affect the values of the average neutron binding energies [13]. By including corrections it can be expected, as the estimates show, that the ratio of the average spectral energies will be equal to 1.0 to 1.1, which agrees with the experimental data. Calculations of the energy spectra and angular distributions of neutrons for the fission of U235 by neutrons with an energy of 14 MeV were carried out by E. I. Sirotinin [6] and for the spontaneous fission of Cf252 by Bowman et al. [14]. In the first case of energy production, neutron evaporation from the compound nucleus with subsequent fission is possible. Naturally, these neutrons which are emitted prior to fission make it more difficult to study the mecha- nism of emission of neutrons associated with the fission process. E. I. Sirotinin came to the conclusion that in this case the division of the neutrons into two components is justified [1] and that the second component is associated with neutron evaporation from the excited fission fragments. In [14], dealing with the investigation of the spontaneous 138 Declassified and Approved For Release 2013/09/24: CIA-RDP10-02196R000700010002-5 Declassified and Approved For Release 2013/09/24: CIA-RDP10-02196R000700010002-5 fission of Cf252 it is reported that about 80-90% of the neutrons from the fission of californium are emitted in the process of isotropic neutron emission from the accelerated fission fragments. The authors suggest that 10 -20% of the neutrons are ejected at the instant of separation of the fission fragments and that this leads in the experiment to significant (- 30%) deviation from calculation at an angle of 90?. It was also observed in the experiment that there was an excess of the measured over the calculated intensity at an angle of 10?. After completion of the present project two reports were published [15, 16] also devoted to the study of the angular and the energy distribution of the neutrons originating as a result of thermal neutron fission of U235. Measure- ments are presented in these papers which are similar to those carried out in the second part of this project. The distributions shown in [16] are close to those obtained by us for the majority of values of the angle, cp. Our data were not compared in detail with the experimental data of [15], since they are presented in a form which makes comparison difficult. It should be noted that the two experimental energy spectra of [15] differ significantly from our data. The authors of [15, 16], during the process of analyzing the data, selected an emission spectrum which should satisfy best of all the observed distributions in the laboratory system. As a result, it was found in [16] that the emis- sion spectra of neutrons emitted by light and heavy fission fragments match (the conclusion is drawn in our paper and in [14]). Another result was obtained by the authors of [15]. They stress the considerable difference between these emission spectra (the average energies of the spectra differ by approximately 30%). The difference between certain results of [15] and the three papers mentioned, obviously, is more likely due to a discrepancy in the experimental data than to any incongruity in the calculations. The conclusions cited in [15 and 161 concerning the emission mechanism agree with .ours. The authors express their thanks to Prof. D. M. Kaminker for assitance in mounting the project in the reactor of the Physicotechnical Institute, Academy of Sciences of the USSR, and also to K. A. Konoplev and D. A. Yashin, and to the entire reactor control team for attention to its operation. The authors also thank S. M. S Solov'yev for preparing the uranium targets and V. A. Bogutskii, V. A. Kanin, ]. M. Karatayev and V. V. Pikunov for assistance with the measurements and processing of the experimental data. LITERATURE CITED 1. Yu. A. Vasil'yey et al., Atomnaya tnergiya, 9, 449 (1960). 2. V. N. Nefedov, ZhgTF, 38, 1657 (1960). 3. M. V. Blinov', N. M. Kazarinov, and A. N. Protopopov, ZhftF, 42, 1017 (1962). 4. M. V. Blinov and N. M. Kazarinov, Pribory i tekhnika eksperimenta, No. 1,40 (1964). 5. F. Maienshtein et al., "Proceedings of the Second International Conference on the Peaceful Uses of Atomic Energy. Selected Reports of Foreign Scientists [in Russian], 2, Moscow, Atomizdat (1959) p. 297. 6. E. I. Sirotinin, Atomnaya tnergiya, 13, 530 (1962). 7. R. Fuller, Phys. Rev., 126, 684 (1962). 8. J. Terrell, Phys. Rev., 127, 880 (1962). 9. J. Terrell, Phys. Rev., 113, 527 (1959). 10. K. LeCouteur and D. Lang, Nucl. Phys., 13, 32 (1959). 11. D. Lang, Nucl. Phys., 26, 434 (1961). 12. D. Thomson, Phys. Rev., 129, 1649 (1963). 13. A. Cameron, Canad. J. Phys., 36, 1040 (1958). 14. H. Bowman et al., Phys. Rev., 126, 2120 (1962). 15. S. Kapoor, R. Ramanna, and P. Rama Rao, Phys. Rev., 131 283 (1963). 16. K. Scarsvag and K. Bergheim, Nucl. Phys., 45, 72 (1963). 139 Declassified and Approved For Release 2013/09/24: CIA-RDP10-02196R000700010002-5 Declassified and Approved For Release 2013/09/24: CIA-RDP10-02196R000700010002-5 CALCULATION OF AVERAGE RADIATIVE CAPTURE CROSS SECTIONS FOR NEUTRONS WITH ENERGIES OF i0-1 05 eV (UDC 539.17.02) A. G. Dovbenko, S. M. Zakharova, V. E. Kolesov and A. V. Malyshev Translated from Atomnaya tnergiya, Vol. 18, No. 2, pp. 114-118, February, 1965 Original article submitted January 31, 1964 The average radiative-capture neutron cross sections of 30 isotopes of Rb, Zr, Mo, Sn, and Sm are calculated on the basis of the statistical theory of nuclear reactions. The calculation uses penetra- bility values for the nuclear surface which were obtained from an optical model and level densities corresponding to a Fermi gas model. The results of the calculations are compared with the avail- able experimental data for an energy of 25 keV. It is shown that satisfactory quantitative estimates can be obtained for the average capture cross-sections of isotopes for which experimental data con- cerning average neutron-resonance parameters are not available. It was shown in [1-4] that the calculation of the energy dependence of average radiative-capture cross sections, within the limits of statistical theory, with penetrability values of the nuclear surface which correspond to an optical model, is in satisfactory agreement with experimental results. It is also known that the absolute value of the cross section is strongly dependent on the value of the average distance between the levels of the compound nucleus and on the average radiation width. These parameters are usually taken on the basis of experimental data in the low- energy range. If no such data are available, the average parameters are obtained by comparing the results of the calculation of the average radiative-capture cross sections with experimental data. The solution of many questions in the field of reactor construction requires a knowledge of how the average radiative-capture cross sections vary as a function of energy. The experimental data available today were obtained chiefly for isotopes which become acti- vated when a neutron is captured. For most isotopes which are not thus activated and for unstable isotopes there are practically no experimental data. It is therefore of interest to calculate the radiative-capture cross sections .on the basis of the average-parameter system mentioned in [5, 6]. For a quantitative comparison of the resulting cross sec- tions, we may use the existing experimental data for an energy of 25-30 keV [7-18]. In addition, by adding the calculated cross sections for the individual isotopes, we can make a comparison with the experimental cross sections for a natural mixture of isotopes, which in many cases are known over a wide range of energies. Calculations were made for the following isotopes: Rb85; Zr"-92,94,96; mo92,94 -98,100; sn112,114 -120 122,124; and smi.44 ,147 -150,152,154. We used the formula of statistical theory which is gdnerally used for calculating average radiative-capture cross sections [1, 2, 15]. Cji (2J+ 1) S a? = T 2(2/+1) (E) 1 D (U d-E,J) , , + (U +E) E2?1T (E k) k ( 1 ) Here E is the kinetic energy of the impinging neutron; /, /' are the orbital moments of the impinging neutron and the 1 . 1 scattered neutron, respectively; J is the total moment of the compound nucleus; i "=-- I ? la= are the spins of the inlet and outlet channels, respectively; I is the spin of the ground state of the target nucleus; lk 140 Declassified and Approved For Release 2013/09/24: CIA-RDP10-02196R000700010002-5 Declassified and Approved For Release 2013/09/24: CIA-RDP10-02196R000700010002-5 TABLE 1. Parameters Used in the Calculation Isotope a , MeV-1 eV U. MeV F eV Y' lib89* 5/2- .8.50 750** 8.58 0.410 Zr99* 0+ 9.0 1.7.104 6.19 0.270 Zr91 5/2 10.2 1.103 6,49 0.245 Zr92 * 0+ 11,0 3.7.103 579 0.270 Zr94 * - 0" 11.6 6.3.103 5.52 0.220 Zr96 * 0' 14.0 2.6.103 4.65 0.160 Alo99 0+ 10.2 2.4.103 6.71 0;270 Alo94 0' 12.6 1.103 6.08 0.220 Alo96 5/2+ 12.6 220 6.44 0.230 IN4o96 - 0+ 12.9 1.103 5.49 0.160 NIo97 5/2' 13.2 220** 6.15 0.200 Alo96 0+ 17.6 270 4.99 0.102 mom 0+ 18.0 430 4.61 0.090 son so14 SOH sn 116 * soi.7 sous son* Snii-29* son Sp 124 Srft144* Srn147 sm148* sm149 scow*. &min* sm 154* 0+ 12.1 850 6.68 0.061 0' 12.2 1.4.103 6.24 0.063 1/2+ 16.5 50** 6.85 0.096 0' 15.5 600 5.39 0.065 1/2+ 15.5 120** 6.60 0.110 0+ 15.0 1 ? 103 5.00 0.093 1/2' 15.5 180** 6.30 0.106 0+ 15.3 1.7.103 4.70 0.108 0+ 16.2 1.7.103 4.40 0.106 0' 15.2 2.103 4.54 0.100 0+ 17.0 325 5.40 0.065 7/2- 20.0 14** 5.77 0.059 0' 22.0 175 4.40 0.063 7/2- 23.6 6** 5.27 0.065 0+ 25.0 115 3.98 0.066 0+ 24.0 87 4,25 0.068 0+ 21.0 740 3.80 0.072 *Experimental data on b are unreliable or unavailable for these isotopes. *For these nuclei, D(U. J) was calculated on the basis of with gj ??--; 1/2. is the spin of the k-th excited level of the target nucleus; EJ and EJ are factors which take account of the num- ber of open channels and are equal, respectively, to the number of values of j and jk satisfying the conditions 1/-1[ 3 MeV). In the case of serpen- tine concrete this value is equal to 10.9 cm. If we take into account the fact that the volumetric weight of ordinary building concrete is 2.4 tons/m3, while that of serpentine concrete is 2.2 tons/m3, the shielding properties that are obtained for the latter with respect to fast neutrons are slightly higher. It is also possible to compare the shielding properties of concretes which have serpentine and limonite as their respective aggregates. The results of an investi- gation on limonite concrete with a volumetric weight of 2.7 tons/m3 were given in [11]; the relaxation length for fast neutrons was found to be equal to approximately 9 cm. Since the chemical compositions of the two concretes differ little from each other, it can be assumed that the neutron relaxation length is approximately inversely pro- portional to the density of the concrete; in this case, the shielding properties of the two concretes are identical. As is known, [12], the removal cross sections for elements with an average atomic weight vary slightly with increase in the neutron energy. Since the serpentine concrete that was investigated consists mainly of elements of this kind, the result that was obtained is in qualitative agreement with the data given in [12]. In actual fact, the main contribution to the magnitude of the removal cross section is made by oxygen (0.036 cm-1), magnesium (0.01 cm-1), and silicon (0.011 cm-1)?elements with average atomic weights. The hydrogen and these elements deter- mine the dependence of the cross section upon the neutron energy. Although the hydrogen cross section alters con- siderably (decreases) in the neutron energy range 1-10 MeV, this is balanced to a large extent by the cross sections of the other constituents of the concrete. From the point of view of the attenuation of 7-radiation, the composition of serpentine concrete is no differ- ent from that of ordinary building concrete. It was reported in [11] that in ordinary concrete the relaxation length of the flux of y-quanta from the active zone of a water-moderated water-cooled reactor is equal to 13 cm. If we make allowance for the difference between the volumetric weights of the two concretes, the value that was ob- tained for the relaxation length of the y-radiation dose rate in serpentine concrete is in good agreement with the data given in [11]. The same can also be said for the result that were obtained by comparing the y-radiation re- laxation lengths in serpentine and limonite concretes, and also in concretes of other compositions [13]. Thus, the results of these experiments show that in comparison with limonite concrete the shielding properties of serpentine concrete with a volumetric weight of 2.2 tons/m3 are slightly better with respect to neutrons and iden- tical with respect to 7-radiation, and, since the chemical composition of this concrete remains unchanged up to a temperature of 480?C, its use can be recommended in the biological shielding of nuclear power installations at least up to temperatures of 450?C. The authors would like to thank all the reactor maintenance staff, and also V. P. Zharkov for his help in car- rying out the experiments and T. V. Ruch'eva for her help in processing the results; they are also indebted to V. M. Isakov, A. P. Kulaev, V. G. Petrov, and A. T. Pogachev for their assitance in making the measurements. LITERATURE CITED 1. Instructions for the Design of Concrete and Ferroconcrete Structures Built with Special (Heavy and Hydrated) Concretes [in Russian], Moscow, Scientific Research Institute of Ferroconcrete, ASA, USSR (1959). 2. I. A. Arshinov, In the Collection: Problems of Reactor Shielding Physics [in Russian], State Press for Atomic Energy, Moscow (1963), p. 337. 156 Declassified and Approved For Release 2013/09/24: CIA-RDP10-02196R000700010002-5 Declassified and Approved For Release 2013/09/24: CIA-RDP10-02196R000700010002-5 3. H. Hungerford et al., Nucl. Sci. and Engng., 6, 396 (1959). 4. A. N. Komarovskii, The Construction of Nuclear Installations [in Russian], State Press for Power Engineering, Moscow ?Leningrad (1961), 5. V. N. Avaev et al.,Atomnaya energiya, 15, 17 (1963), 6. V. N. Avaev et al., In the Collection: Problems of Reactor Shielding Physics [in Russian], State Press for Atomic Energy, Moscow (1963), p, 270, 7. Yu. A. Egorov and Yu. V. Pankrat'ev, Ibid., ID. 304. 8. A. P. Veselkin et al., Atom naya energiya, 16, 32 (1964). 9. Kh. D. Androsenko and G. N. Smirenkin, Pribory i tekhnika eksperimenta, No. 5, 64 (1962). 10. Yu. A. Egorov and E. A. Panov, Pribory i tekhnika eksperimenta, No. 4,57 (1961). 11, V. S. Dikarev et al., Atom naya energiya, 1, No. 5, 136 (1956). 12, B. I. Sinitsyn and S. G. Tsypin, Atomnaya?energiya, 12, 306 (1962). 13. V. N. Avaev et al., In the Collection: Problems of Reactor Shielding Physics [in Russian], State Press for Atomic Energy, Moscow (1963), p. 193, 157 Declassified and Approved For Release 2013/09/24: CIA-RDP10-02196R000700010002-5 Declassified and Approved For Release 2013/09/24: CIA-RDP10-02196R000700010002-5 STUDY OF THE NEUTRON MODERATION PROCESS IN BERYLLIUM AND BERYLLIUM OXIDE BY A PULSE METHOD (UDC 621.039.512.4) I. F. Zhezherun Translated from Atomnaya Energiya, Vol. 18, No. 2, pp. 127-135, February, 1965 Original article submitted November 30, 1963; Revision submitted February 29, 1964 The moderation time was measured for neutrons up to energies of 1.46, 0.3, 0.178, and 0.0976 eV and also the thermalization time below an energy of ? 0.1 eV. The time distribution of moderated neutrons was obtained to an energy of 0.3 eV. The measurements made it possible to calculate the correction for moderation of neutrons over the energy range below 1.46 eV and to obtain the square of the moderation length of fission neutrons at various energies close to the thermal region. The square of the moderation length L for the majority of moderators used in nuclear technology has been measured up to an energy of 1.46 eV (indium resonance). A correction for the moderation of neutrons to thermal energy is interpolated by a numerical method and usually contains a significant indeterminacy due primarily to the fact that the average logarithmic energy loss g in this region is unknown. The measurement of 14 down to lower energies has been carried out only for beryllium oxide to 0.3 eV (Pu239 resonance) [1]. The neutron moderation time and its fluctuations have been studied theoretically in a number of papers [2-6]. Interesting results are given in the paper by I. G. Dyad'kin and E. P. Batalina [7] who considered the time depend- ence of the space-energy distribution of neutrons N(r, u, t) on a pulsed source having, an initial velocity vo. They found that at distances from the source r Xua (where X is the scattering length, u is the lethargy, and B is a con- stant of order unity) N (r, u, st (r, u) No (u, [1 + e u, 01, (1) i. e., the space-energy (stationary) distribution Nst(r, u) is derived by the energy-time distribution No(u, t), where No(u, t) = 2 v Vol vt v): ' (2) for t > X/(vo? v). Thus, the time distribution of neutrons having a velocity v agrees with a Poisson probability for the appear- ance of 2/g neutrons after a time t for conditions that the probability of appearance of neutrons at any instant is identical and equal to (v/X)dt. It should be noted that No(u, t) is almost independent of the initial neutron velocity vo and attains a maximum at the instant 158 tmax .74'; {(2 Vr213+up2u2 [ 23ct (I Vr2+13ufl2u2 (3) Declassified and Approved For Release 2013/09/24 : CIA-RDP10-02196R000700010002-5 Declassified and Approved For Release 2013/09/24: CIA-RDP10-02196R000700010002-5 2 5 6 7 reZ. Ad, Fig. 1. Geometry of the experiment for measuring the transmissivity of boron filters (transverse sec- tion): 1) filter; 2) boron carbide collimator; 3) cadmium sheath; 4) counter shielding screen; 5) BF3 cpimters; 6) collimator ports; 7) collimator mounting (or support); 8) moderator block. The block shielding (Cd and B4C) is not shown. 0 90 0.80 0.70 0.60 ztt. 0? 50 - 0.40 0.30 0.20 0.10 0 78 1 2 3 4 5 6 W ', . Ilirelial tillifillii 111111111iiiII 111$11111 iftillil 11111 igelll iI I , .11 I!..IIII 3 4 6 8 10 20 30 40 60 80100 ISO ZOO Msec Fig. 2. Moderation time measurement results: 1, 2) count rate N(t) of the 0.3-eV neutron detector in the block of Be and Be() respectively; 3, 4) reciprocal transmissivity 11-1(t) of the cadmium filter in Be and Be(); 5, 6) the same for tlie sama- rium oxide filter; 7, 8) the same for the indium filter. All curves are normalized to unity at the maximum. One of the beams from the linear accelerator at the I. somewhat depending on r (a is a very slowly changing func- tion of u). The additional weak dependence of N(r, u, t) on time is contained in the term [1 + e(r, u, t)], which however differs little from unity for t tmax ? At, where At is the dispersion of tmax; tmax is the average moderation time of neutrons having a velocity v. The moderation time at a velocity v, obviously, will be equal to tm = tmax X/v. One paper [8] and two notes [9, 10] are known in which tm is measured in water down to thermal energies; in two other papers tm 160 ?sec is derived for graphite [11] and tm = 230 ? 30 ?sec for beryllium oxide [12]. The inadequacy of these papers is that it is not defined precisely in them to what energy the stated values for tm should be related. Some projects have been devoted to the study of the last stages of moderation?the establishment of the equilib- rium spectrum?using a pulsed neutron source. Of the theo- retical reports we shall refer only to [13], in which the rela- tionship was found between the coefficient of diffusion cool- ing C and the thermalization time without using the concept of neutron temperature, and the possibility is shown of de- termining tth experimentally by measuring the damping de- crement of the first harmonic in a similar manner as the dif- fission coefficient is determined from the damping decre- ment of the zero harmonic. The experimental reports [12, 14-16] should be mentioned, in which tth was measured in beryllium oxide with a density of 2.96 g/cm3 by various methods (transmission of a filter of a 1/v absorber, measure- ment of the coefficient of diffusion cooling , etc.) and a value was obtained of tth = 165 ? 10 Msec. For beryllium (density 1.79 g/cm3), the approximate value of tth = 172 ?sec is given in [17], found from measurement of the coefficient of diffusion cooling. In the present project, the moderation time was mea- sured down to various energies E 1.46 eV, and also the thermalization time in beryllium and sintered beryllium oxide. The results of the measurements permitted data to be obtained concerning the moderation length of neutrons in Be and Be() below 1.46 eV. Measurement Procedure The neutron moderation time was determined by measuring the transmissivity fl(t) of filters with a strong resonance in the absorption cross section as a function of the time t elapsed from the instant of the neutron pulse. V. Kurchatov Institute of Atomic Energy [18] was used as a pulsed neutron source. The pulse duration was 0.5-1 Msec and the pulse repetition frequency was 50-100 cps. The filters were in the shape of a cylinder and were attached to a small cylindrical BF3 counter, inserted in the modera- tor block. Filters were used of 0.073 g/cm2 indium, 0.086 g/cm2 cadmium and 0.047 g/cm2 samarium oxide, which have resonances at 1.46, 0.178, and 0.0976 eV respectively. In addition to the filters, a pulse detector for neutrons with energy 0.3 eV was used (a plutonium chamber enclosed in a screen of a mixture of samarium and gadolinium oxides) [19], which was shown to be very convenient for measuring not only tm but also for measuring the time distribution No(u, t). 159 Declassified and Approved For Release 2013/09/24: CIA-RDP10-02196R000700010002-5 Declassified and Approved For Release 2013/09/24: CIA-RDP10-02196R000700010002-5 TABLE 1. Measured and Calculated Values of the Moderation Time at Different Energies, ?sec Resonance energy, eV In beryllium In beryllium oxide calculation experiment calculation experiment 1.46 (Indium) 7.2 7.5 ? 1 9.3 9.5 ? 1 0.3 (Plutonium) 15.7 17.5 ? 1 19.2 26 ? 2 0.178 (Cadmium) 20.4 40 ? 3 26.3 51 ? 3 0.0976 (Samarium) 27.6 73 ? 5 34.3 88 ? 5 The detectors were positioned on the axis of the moderator block, coincident with the axis of the beam. By changing the position of a detector along the axis, the relationship could also be investigated between tm and the distance r to the neutron source. The mean density of the material in the beryllium and beryllium oxide blocks was 1.79 gicm3 respectively. The thermalization time was determined by measuring the transmissivity ir(t) of plane boron filters containing 0.012 and 0.023 g/cm2 of boron. The filters, with dimensions 12 x 30 cm, were inserted in slits below the neutron collimator located at the moderator block (Fig. 1). The collimator was made of cadmium and boron carbide and had ports with a diameter of 35 mm and a height of 120 mm. Above the collimator were located four B10F3 counters connected in parallel, with a diameter of 20 mm and length 25 cm. The counters were screened by cadmium, boron carbide and paraffin so that neutrons from the moderator block could only strike them through the ports of the col- limator at an angle > 80? to the surface of the block. The distance between the block and the counters was equal to 15 cm. The moderator blocks were in the shape of a cube or a parallelipiped with dimensions 60 x 60 x 60 and 50 x 50 x 50 cm for beryllium, and 80 x 70 x 75 and 60 x 60 x 60 cm for beryllium oxide; they were covered on all sides by a layer of cadmium (0.86 g/cm2) and boron carbide (5 g/cm2). Data concerning the diffusion param- eters of these materials are given in [17, 20]. The counting rate of the counters with and without filters as a function of time, from which the transmissivity rim was determined, were measured by means of a time analyzer, used in [17, 20] and also a 110-channel analyzer, with a minimum channel width of 1 ?sec. The source strength was controlled by two monitors. The background (which did not exceed 1% of the effect) was determined by the count rate at the instant of time immediately prior to the neutron pulse. Measurement Results and Discussion Moderation Tim e. The results of measurement of the moderation time are shown on a semilog scale in Fig. 2. For beryllium these measurements were carried out in the block with dimensions. 50 x 50 x 50 cm and for beryllium oxide in the blocks with dimensions 80 x 70 x 75 and 60 x 60 x 60 cm. The time elapsed from the instant of the neutrons pulse is plotted along the x axis and along the y axis is plotted the count rate N(t) of the resonance detector of 0.3-eV neutrons and the reciprocal transmissivity IT-1(t) for the resonance filters. The time corresponding to the maximum is equal, obviously, to the moderation time tm to a given energy plus the time of flight of the neutron from the site of the last collision up to absorption in the detector tfj. = [X(v) ? 1/2d]iv (d is the average cross section of the detector, taking account of the void at the place where it is located) and the time of flight from the accelerator target to the block (? 0.5 ?sec). , The values obtained for tm are given in Table 1. The errors shown (from 1 to 10 ?sec in different measure- ments) are associated with the finite width of the channel and the inaccuracy in calculating tfi. For comparison, the values are given for tm obtained in accordance with formula (3) on the assumption that the factor in the curly brackets, which takes into account the relationship between tmax and the distance r to the source, is equal to unity. Under our conditions, the sources are obviously the sites of the primary collisions of the neutrons from the beam with the moderator nuclei, which are located in a plane layer of the front face of the moderator block with a thick- ness of about 2X(v0) p:s 5-7 cm. The measurements with the 0.3-eV neutron detector in the blocks at various dis- tances (r -? 30 cm) from this layer did not indicate a dependence of tm on r, which justifies the assumption made above. 160 Declassified and Approved For Release 2013/09/24: CIA-RDP10-02196R000700010002-5 Declassified and Approved For Release 2013/09/24: CIA-RDP10-02196R000700010002-5 11(0 0.80 0.70 0.60 0.50 0.40 0.30 /00 80 60 40 20 ? ,i/T-% . / .% ? N / ? % f \ . \ + ? ? -I + 4 . ? , f 0 0 0 i 10 20 30 40 50 1.1ec Fig. 3. Comparison of the experimental time distribu- tion of neutrons with energy 0.3 eV with the Poisson distribution: 0) beryllium; e) beryllium oxide. A A? A A A ..- A + a t 0.577 A a ? 2 2. A 0.355 A ; 0 160 320 480 640 800 .960 1120 1280 ?sec Fig. 4a. Transmissivity of boron filters for blocks of beryllium. The curves are derived visually according to experimental points from different measurement series: 1, 2) for filters containing 0.012 and 0.023 g/cm2 of boron respectively. The values for tm shown in Table 1 will be valid also for fission neutrons, since the spectrum of accelerator neutrons is close to the fission neutron spectrum. It can be seen from the table that for energies less than 1.46 eV the experimental value of tm is greater than the calculated value. This is obviously associated with the fact that g in this region is lower than the value of g for collisions with a free atom. The measurements made with the 0.3 eV neutron detector make it possible to compare the experimental dis- tribution No(u, t) with the theoretical distribution [see formula (2)]. Figure 3 shows the experimental data for beryl- lium and beryllium oxide and the matched (accoreing to experimental data) Poisson distributions for No (u, t) 2 vt ( "l e? with 2/g = 12 for beryllium (continuous line) and 2/g = 18 for beryllium oxide (dashed line). 161 Declassified and Approved For Release 2013/09/24: CIA-RDP10-02196R000700010002-5 280 0 70 0.60 0.56 0.40 0.30 Declassified and Approved For Release 2013/09/24: CIA-RDP10-02196R000700010002-5 .?-0 1 o. . ? 0.517 0.355 I t60 320 480 640 800 860 1120 180 1440 ?sec Fig. 4b. Transmissivity of boron filters for blocks of Be() (for legend see Fig. 4a). It can be seen that they agree well. The divergence is notice- able only at large values of t, which is associated, obviously, with the effect of the term in the square in formula (1) (see [7]). By using the fact that in a Poisson distribution the dis- persion is equal to the mean value, it is possiblt to obtain alio from the relationships (vtmax/X)Be = 12 = 2/Be and (vtmax/X)Be0 = 18 = 2/ggeo the moderation time tm to an energy of 0.3 eV for beryllium and beryllium oxide. For this it is necessary to subtract from tmax the dispersion due to the width of the energy sensitivity region of the detector [19], equal to At = 1/2. (AE/E)tm (2.9 and 4.3 ?sec for beryl- lium and beryllium oxide respectively), and also the time of .flight at an energy of 0.3 eV. As a result, we obtain a value for tm equal to 17.3 ?sec for beryllium and 28 Msec for beryl- lium oxide, which is in agreement with the values found ac- cording to the position of the maximum. The average logari- thmic energy losses at an energy of 0.3 eV are as follows: Be = 0.19, 13e0 = 0.12. Thermalization Time. The results of measur- ing 11(t) for the boron filters are shown in Fig: 4 for blocks of beryllium (60 x 60 x 60 cm) and beryllium oxide (80 x 70 x 75 cm). It follows from the figures that for a time t 1200 ?sec in beryllium and t 1400 ?sec in Be() , the transmissivity attains a minimum asymptotic value corresponding to the estab- lished neutron spectrum. The asymptotic values have been mea - sured with a high degree of accuracy and have been shown to be identical for beryllium and beryllium oxide, as would be ex - pected: 0.577 ? 0:003 and 0.355?0:002 for filters containing 0,012 and 0.023 g/cm2 of boron respectively. Similar transmission curves were obtained also for blocks of smaller dimensions with a somewhat smaller as- ymptotic transmission. Thus, for a beryllium block with dimensions 50 x 50 x 50 cm it was found to be 0.0568 ? 0.008 and 0.346 ? 0.002 respectively. In order to obtain data concerning the neutron energies from the transmissivity H(t), it was assumed that the neutron 'spectrum has a maj E 2) = E "1 Lc (9) (D is equal to 0.50 and 0.54 cm for Be and Be0 respectively.) Thus, for example, the value BeLj (1.46 -* 0.3 eV) = 5.7 ? 1.2 cm2; Be0I4 (1.46 -* 0.3 eV) = 11.4 ? 1.2 cm2 are in good agreement with the value of 12.5 ? 2.5 cm2 obtained for Be0 from direct measurements of L2 up to 1.46 and 0.3 eV [1], which indicates that the accuracy of formula (7') is also acceptable over the interval 1.46-0.3 eV; BeLl (0.3 -* 0.178 eV) = 7.4 ? 0.8 cm2; Be01-4 (0.3 0.178 eV) = 8.7 ? 0.9 cm2; Be-11 (0.3 0.13 eV) = 11.9 ? 1.2 cm2; Be0I4 (0.3 -* 0.13 eV) = 14.3 ? 1.4 cm2 etc. In regions where formula (4) is valid, it is easy to obtain, by using formulas (8) and (9), that /4 (E1 ---->E2)= Dvetth {2 (- -11-41 (VE2 -HY-c) E2 ln ETe (17W, --:--11E-) (VE72.- VED (10) i. e., for E2 Ee, co. The latter result, as already repeatedly mentioned (see', for example [27]), confirms the fact that it is incorrect to assume the value of E = kTe as the lower limit of the integral in Eq. (9) for calculating the moderation length down to thermal energy. Conclusions The measurements carried out indicate that the moderation process for neutrons in beryllium and beryllium oxide up to an energy of 1.46 eV takes place in collisions with free atoms and lasts for a relatively short time, not exceeding 10 ?sec (Table 2). Over the interval 1.46-0.3 eV the effect of the atomic bonds in the crystal lattice is already noticeable, especially for Be0. The logarithmic energy loss g is reduced on the average by 10% with Be and by 60% with Be0 relative to its value for the free atom. The moderation time over this interval is 11/2 to 2 165 Declassified and Approved For Release 2013/09/24: CIA-RDP10-02196R000700010002-5 Declassified and Approved For Release 2013/09/24: CIA-RDP10-02196R000700010002-5 times greater than tm up to 1.46 eV. Over the interval from 0.3 to - 0.07-0.08 eV (below which a spectrum is established which is close to Maxwellian), E for Be and Be0 is reduced to - 25% of its value for a free atom. The moderation time over this interval is six-seven times greater than tm up to 1.46 eV. The energy-time distribution of neutrons in the region prior to - 0.07 eV can be obtained by formula (2), if the values of E given above are sub- stituted in it. Below - 0,07-0,045 eV the moderation proceeds very slowly and lasts on an average for 185 20 ?sec for beryllium and 204 ? 25 ?sec for beryllium oxide. The value of L up to 0,13 eV (5.2 kTo) given in Table 2 for beryllium is somewhat greater (for scaling at a density of 1.84 g/cn73) than the value of the Fermi age given in [29], in which the lower limit in the integral of Eq. (9), in accordance with thermalization theory, is assumed equal to 5.2 kTo. The value of LI up to 0.3 eV for Be0 is in good agreement with the value of 104.5 2 cm2, obtained by direct measurements of L up to an energy of 0.3 eV for the same for beryllium oxide. In conclusion, the authors express their thanks to the operating personnel of the accelerator in the beam of which the measurements were carried out, to M. P. Shustov for the numerical calculations, to A. A. Osochnikov and G. V. Yakovlev for assistance in maintaining the analyzer's and to Yu. D. Kurdyumov and G. P. Perov for assitance with the measurements. LITERATURE CITED 1. I. F. Zhezherun et al., Atomnaya energiya, 13, 258 (1962). 2. J. Sykes, J. Nucl. Energy, 2, 31 (1955). 3. G. Hayneman and M. Crouch, Nucl. Sci. and Engng., 2, 626 (1957). 4. J. Waller, Proc. of the Second. Intern. Conf. on the Peaceful Uses of Atomic Energy, Geneva, Unit. Nat., Vol. 16 (1958), p. 450, 5. L. Pol and G. Nemeth, Nucleonik, 1, 165 (1959). 6. G. Kosaly and G. Nemeth, Ditto, p. 225. 7. I. G. Dyad'kin and E. P. Batalina, Atomnaya energiya, 10, 5 (1961). 8, M. F. Krouch, Nucl. Sci. and Engng., 2, 631 (1957). 9. J. De Juner, Nucl. Sci. and Engng., 9,-408 (1961). 10, E. Moller and N. Sjostrend, Nucl. Sci, and Engng., 15, 2 (1963), 11, A. V. Antonov, Trudy fizicheskogo instituta im. Lebedava, 14, 147 (1962). 12, S. Iyenger et al., Proc. Indian Acad. Sci. A, 45, 215 (1957), 13. S. N. Purohit, Nucl. Sci. and Engng., 9, 157 (1961), 14, R. Ramanna, Cf. [4], p. 315, 15. V. A. Couhall et al., Ditto, ID. 319. 16. S. Iyenger et al., Proc. Indian Acad. Sci. A, 45, 224 (1957), 17. L F. Zhezherun, Atomnaya energiya, 16, 224 (1964), 18. R. M. Voronkov et al,, Atomnaya energiya, 13, 327 (1962). 19. I. F. Zhezherun, I. P. Sadikov, and A. A. Chernyshov, Pribory i tekhnika eksperimenta, No. 3, 43 (1962). 20, I. F. Zhezherun, Atomnaya energiya, 14, 193 (1963). 21. K. Singvi and L. Kokhari, In the book: "Proceedings of the Second International Conference on the Peaceful Uses of Atomic Energy, Geneva, 1958," Collected Reports of Foreign Scientists, Vol. 2, Moscow, Atomizdat [in Russian] (1959), p, 675. 22. J. Yuz and R. Schwartz, Atlas of Neutron Cross Sections, Izd. IL, Moscow, Atomizdat [Russian translation] (1959). 23. I. F. Zhezherun, I. P. Sadikov, and A. A. Chernyshov, Atomnaya energiya, 13, 250 (1962), 24, K. Singwi, Arkov fys., 16, 385 (1959), 25. K. Beckurst, Nucl. Sci. and Engng., 2, 516 (1957). 26. J. Meadows and J. Whalen, Nucl. Sci. and Engng., 13, 230 (1961). 27. E. Cohen, In the book: "Experimental Reactors and Reactor Physics," (Reports of Foreign Scientists at the International Conference on the Peaceful Uses of Atomic Energy, Geneva, 1955), Moscow, Gostekhteorizdat [in Russian] (1956), p. 257. 28. j. yuz, Neutron Research on Nuclear Reactors [Russian translation], Izd. IL (1954), p. 161. 29. L. Weinberg and E. Wigner, Physical Theory of Nuclear Reactors [Russian translation], Moscow, Izd. IL (1961), 13. 310, 166 Declassified and Approved For Release 2013/09/24: CIA-RDP10-02196R000700010002-5 Declassified and Approved For Release 2013/09/24: CIA-RDP10-02196R000700010002-5 EXPERIMENTAL INVESTIGATIONS OF SHIELDS ON THE RIZ STAND (UDC 621.039.538.7) S. P. Belov, V. A. Dulin, Yu. A. Kazanskii, V. I. Popov, and S. G. Tsypin Translated from Atomnaya gnergiya, Vol. 18, No. 2, pp. 136-140, February, 1965 Original article submitted April 2, 1964 The present article describes a stand with a zero-power reactor designed for investigating the pro- cesses occurring in that part of the shield which is in close contact with the reactor core. If the processes occurring in this part of the shield (formation of the neutron spectrum and generation of strong y-radiation) are known, the dimensions and the weight of the reactor's entire shield can be properly calculated. The results obtained in measuring neutron spectra and investigating shielding materials (iron, nickel, and borated nickel) on the stand are given. Studies of the processes occurring in that part of the shield which is in direct contact with the reactor core are very important, since the neutron spectrum and powerful capture y -radiation are generated in this part of the shield. These processes basically determine the dimensions and the weight of the entire shield. It is most con- venient to investigate experimentally these rather complex problems by means of a zero-power reactor, where the shield under investigation can readily be mounted or dismantled. The use of a zero-power reactor for investigating secondary y-radiation is also convenient with regard to the possibility of quickly changing the power level in a wide range, securing good ratios of the background to the effect to be measured, and varying the dimensions and design of the shields under investigation. For experimental investigations of shielding, we constructed the RIZ stand with a zero-power,water-moderated reactor. In designing the stand, we considered the possibility of varying the emerging neutron spectrum, convenient arrangement of the shielding materials to be investigated, and the performance of experiments. Since the main purpose of the RIZ stand was to investigate the yield of capture y-radiation and the neutron spectrum, attention was mostly paid to the possibility of securing the optimum ratio of the neutron flux to the y -radiation at the stand's operating surface. Description.of the Core, the Shielding Screens, and the Control System The zero-power water-moderated uranium reactor which we use (the prototype of this reactor was developed under the direction of V. A. Kuznetsov) has a cylindrical core with a diameter of 335 mm and a height of 275 mm. The core is filled with distilled water, into which the lattice with the fuel elements is immersed. The fuel ele- ments consist of 90%-enriched uranium dioxide, which is packed in hermetically sealed stainless-steel tubes. Each rod contains 10.5 g U235; the over-all core charge with respect to U235 amounts to 3.5 kg. The lateral shield of the core consists of iron, water, and concrete layers with an over-all thickness of about 130 cm (Fig. 1). The lower shield consists of a miyture of iron and water (60% iron by volume) with an over-all thickness of 35 cm. A shield consisting of a boron carbide layer with a thickness of 4.5 g/cm2 and a bismuth layer with a thickness of 8.5 cm is provided at the upper end-face of the core; the diameter of this shield is 110 cm; beyond the shield is a ring with a width of 35 cm, which consists of boron carbide (7 g/cm2) and lead (6.5 cm) (see Fig. 1). 167' Declassified and Approved For Release 2013/09/24: CIA-RDP10-02196R000700010002-5 Declassified and Approved For Release 2013/09/24: CIA-RDP10-02196R000700010002-5 " 4 MONIMMENNOIM. \\\,\ Steel M Lead M Bismuth Boron carbide Fig. 1. Schematic diagram of the core and the shielding screens of the RIZ stand reactor. 1) Core; 2) operating surface; 3) room for the control system and shielding; 4) channels for the control eqiiipment detectors. The purpose of the shield at the upper end-face of the core is: 1) to reduce materially the yield of hard y -radiation from the core, the structure, and the lateral reflectors and shields; 2) to attenuate the soft portion of the spectrum of neutrons emerging from the core; this task is fulfilled by boron carbide that is located directly at the end-face of the core; 3) to reduce the effect of the shields under investigation on the reactor's reactivity. Figure 2 shows the external view of the shield and the operating surface of the stand at the reactor's upper end-face. The reactor is controlled from a room located under the iron-water shield. Boron rods, which are arranged in the core along a diameter of 215 mm, serve as the regulating and emergency rods. Quick draining of water from the core is also provided for the emergency shutdown of the reactor. The detectors of the control and the emergency equipment (boron-coated chambers and counters filled with boron trifluoride) are located in the water layers of the lateral shield at radii of 32 and 62 cm from the core center. The instruments of the control equipment and of the emergency protection channels are mounted in the control panel room (Fig. 3), The reactor is equipped with an automatic device for raising the power from the zero level and maintaining it at the assigned level, which is achieved (from the control panel) by meaps of a remote control system for filling the core with water. A fission chamber with Th232, which can be moved inside a special channel along the generatrix of the core by means of a remote control device, serves as the monitor of the reactor's power level. This makes it possible to extend the range of counting rate measurements by a factor of 15-20. 168 Declassified and Approved For Release 2013/09/24: CIA-RDP10-02196R000700010002-5 Declassified and Approved For Release 2013/09/24: CIA-RDP10-02196R000700010002-5 Fig. 2. External view of the shield and the operating surfa6e of the RIZ stand reactor (top view). Fig. 3. Control panel of the RIZ stand reactor. Since the stand is basically used as a source of reactor-spectrum neutrons, and changes in the reactor's physi- cal parameters are connected only with variations in its reactivity as a result of addition of the materials under in- vestigation at the upper end-face, the core is constructed so that excess reactivity does not exceed 0.3% if the core is completely filled with water and the material under investigation is absent. This considerably simplifies the control reactor and enhances its safety. 169 Declassified and Approved For Release 2013/09/24: CIA-RDP10-02196R000700010002-5 Declassified and Approved For Release 2013/09/24: CIA-RDP10-02196R000700010002-5 Fig. 4. Calculated spectrum of neutrons emerg- ing from the upper reflector of the RIZ stand re- actor. 5.) 1000 100 10 x5 I 0 1 4 5 6 7 8 9E5,MeV Fig. 5. Fast neutron spectra measured by means of a scintillation spectrometer. 1) At the center of the stand's operating surface; 2) and 3) at dis- tances of 40 cm and 1 m from the center of the stand's operating surface, respectively. 30 5.) 15 0 71=1 5 6 7 8 9 Ei, MeV Fig. 6. y -radiation spectrum measured by means of a scintillation y-spectrometer at a height of 1 m above the center of the operating surface of the RIZ stand reactor. 170 The upper reflector, which consists of boron carbide and bismuth, reduces the effect of the material under inves- tigation on the reactivity by not more than 0.1010. 1. Characteristics of the Stand as a Radiation Source Figure 4 shows the spectrum of neutrons emerging from the upper reflector, which was calculated by V. P. Kochergin. Due to filtration by boron that is contained in the reflector, the neutron spectrum is much harder than the neutron spectrum of a thermal reactor. By varying the boron thickness in the reflector, it is possible to change the neu- tron spectrum in the energy range below 10 keV and thus simulate the neutron spectra of different thermal and inter- mediate reactors. The fast neutron spectrum was measured by means of a single-crystal scintillation neutron spectrom- eter [1]. The measurement results are given in Fig. 5. The solid curve indicates the U235 fission spectrum, while the dashed curve shows the same spectrum with an allowance for the attenuation by bismuth in the extraction cross section. Figure 6 shows the spectrum of y -radiation emerging from the surface of the bismuth shield, which was measured by means of a single-crystal scintillation spectrometer for energies above 3 MeV. The hard portion of the spectrum is obviously due to the capture y-radiation in iron (in the struc- ture, the reflector, etc.). The neutron and y-radiation spectra were measured in the same geometry and were reduced to the same reactor power level. This made it possible to estimate the ratio of the neutron flux to the y-radiation above the operating sur- face of the stand. The ratio of the number of neutrons with an energy above 0.5 MeV to the number of y -quanta with an energy above 3 MeV was equal to ? 20. The ratio of the total number of neutrons to y-radiation with an energy above 1 MeV, which was estimated with an allowance for the calculated spectrum on the basis of measurements with a stilbene crystal (in the 1-3 MeV range), was equal to ? 7. The fairly good ratios of neutron fluxes to y-radia- tion that we obtained made it possible to measure neutron spectra and even the angular distribution of neutrons, to measure the yield of secondary y-radiation from different materials, and to compare spectra of capture y-radiation. As an example of the latter measurements, we can cite [2], where considerable distortions of the y-radiation spectrum for such important structural materials as nickel, iron, and copper were detected. The described stand was used for many experiments in investigations of the yield of capture y-radiation for a number of structural and shielding mate- rials by means of the method described in [3]. The measurement results for iron and nickel are given below. Declassified and Approved For Release 2013/09/24: CIA-RDP10-02196R000700010002-5 Declassified and Approved For Release 2013/09/24: CIA-RDP10-02196R000700010002-5 Results of Measurements on the RIZ Stand Iron Nickel Borated nickel (2% boron by weight) thick- ness, cm relative yield of y-radia- tion ratio of y-radia- tion fluxes B,?1? thick- ness, cm relative yield of y -radia- tion ratio of y-radia- tion fluxes 5, ok thick- ness, cm relative yield of y -radia- tion ratio of y-radia- tion fluxes 5,5 10 20 40 0.88 1 0.78 0.36 14.1 10,3 8,2 7.6 0,80 1,03 1.21 1,17 4,8 9,6 20 30 0,81 1 0,69 0,36 15,4 9,5 6,4 7,3 1,06 1,47 2,12 1.82 4.7 9,4 13.1 20,3 28 0.54 0,43 0.32 0,20 0.10 ? 1.6 ? 2.0 ? ? 1,07 ? 1,0 0.96 Investigation of the Yield of Capture Radiation from Iron and Nickel Prisms with different thicknesses, which were made up of 900 x 1000 x 9 mm iron sheets, 800 x 800 x 8 mm nickel sheets, and borated-nickel sheets with 2% boron by weight, which had a diameter of 900 mm and a thick- ness of 15-20 mm, were placed on the operating surface of the stand. Shields made of boron carbide, paraffin, and mixtures of boron carbide, paraffin, and water were used for re- ducing the neutron radiation background. These shields, which surrounded the prism on all sides, were placed on the surface of the shield under investigation. The 7-radiation detector was also surrounded with boron-paraffin and bismuth shields. It was mounted at distances of more than 100 cm from the surface of the shield under investigation. For measuring the background, the solid angle formed by the detector and the prism surface was cut off by a bismuth shield with a thickness of 8-9 cm. In the y-radiation energy range from 3 to 6 MeV, the effect-to-background ratio was equal to unity even for iron with a thickness of 40 cm. As in [3], the end result of the experiments was the determination of the secondary radiation coefficients 8?the ratios of the total number of 7-quanta with an energy exceeding a certain threshold Ethr that emerge from the shield surface to the total number .of neutrons emerging from the same surface. The table provides the secondary radiation coefficients and the relative yields of capture y-radiation from nickel, borated nickel, and iron as functions of the shield thickness. For iron, Ethr = 5 MeV, while, for nickel and borated nickel, Ethr = 7.5 MeV. The secondary radiation coefficients for a Po?a?Be-source placed inside a flat iron layer were given in [3]. Comparing our results with the data for iron from [3], we see that, for thicknesses exceeding 20 cm, the secondary radiation coefficients are in agreement within the limits of measurement accuracy (the errors in our results are equal to 10-13%) in spite of the difference between the neutron spectra of such sources as a Po?a?Be-source and the RIZ reactor. Considerable discrepancies are likely to be observed for smaller thicknesses due to the fact that the influence of the iron layer under the neutron source is manifested in measurements with a Po?a?Be-source. In the case of a two-component shield consisting of a heavy and a hydrogenous medium, the capture y-radia- tion considerably increases, since the neutrons reflected by the hydrogenous medium are absorbed in the heavy shield. The table also provides the ratios of 7-radiation fluxes for the case where the heavy shield is in contact with water and the neutrons reflected by boron carbide are blocked (a B4C thickness equal to 0.5 g/cm2 is suffi- cient for this purpose). It should be mentioned that these ratios depend on the thickness of the next shield because of the different angular distributions of the 7-radiation produced by reflected and transmitted neutrons. This prob- lem was discussed in detail in [4, 5]. In conclusion, the authors consider it their pleasant duty to express their deep gratitude to A. I. Leipunskii and I. I. Bondarenkol for their continued interest in the experiments performed on the RIZ stand, toy. A. Kuznetsov ilDeceased. 171 Declassified and Approved For Release 2013/09/24: CIA-RDP10-02196R000700010002-5 Declassified and Approved For Release 2013/09/24: CIA-RDP10-02196R000700010002-5 for his valuable assistance in constructing the stand, and to A. F. Popov and A. F. Sotnikov for their work on the construction and adjustment of the control and safety equipment for the stand. LITERATURE CITED 1, V. A. Dulin et al., Pribory i Tekhnika Eksperimenta, No. 2, 39 (1961). 2. A. T. Bakov et al., ZhETF, 44, 3 (1963). 3. A. T. Bakov et al., Atomnaya Energiya, 13, 31 (1962). 4. D. L Broader et al., Problems in the Physics of Reactor Shielding [in Russian], Moscow, Gosatomizdat (1963), p. 112. 5. B. F. Gromov et al., Atomnaya Energiya, 18, 69 (1965). 172 Declassified and Approved For Release 2013/09/24: CIA-RDP10-02196R000700010002-5 Declassified and Approved For Release 2013/09/24: CIA-RDP10-02196R000700010002-5 A WHOLE-BODY COUNTER (UDC 539,107) Yu. V. Sivintsev, 0; M. Arutinov, V. A. Kanareikin, and M. A. Banov Translated from Atomnaya gnergiya; Vol. 18, No. 2, PP. 141-147; February; 1965 original article submitted June 24, 1964 A description is given of a whole-body counter using NaI(T1) crystals which was constructed at the I. V. Kurchatov Atomic Energy Institute in 1961. Results of work on improvement of instrument parameters are presented. As a result of this work, a background count rate per kilogram of scintil- lator equal to 7800 cts/h was obtained for the energy range 150-2100 keV. From calibrations per- formed with water solutions of K4? and Cs137 in a phantom, it was determined that the sensitivity for a y -emitting isotope in the human body was 1.4. 10-11 Ci/kg. The mean potassium content in males of middle age was 1.96 ? 0.08 g K/kg body weight, and for females of the same age, it was 1.53 ? 0.04 g K/kg weight. A sharp increase in the specific activity of Cs137 in the human body ap- peared during the period from September, 1962 to August, 1963 (from 35 to 135 nCi/g K) resulting from contamination of the biosphere by the products of nuclear explosions. The comparatively great hazard from internal radiation, the negligibly small permissible level of iso- topes in the human body (fractions of a microcurie in the entire body), and me associated need for reliable identi- fication and measurement of quantities of radioactive materials led to the construction of a whole-body counter, Similar equipment has been built in recent years in the United States, England, France, and other countries [1]. The high sensitivity of such spectrometers makes it possible not only to determine the type and absolute amount of radio- active isotopes which have entered the human body, but also to solve other problems, for example, such as the de- termination of the potassium content in vivo, the measurement of absorbed dose for neutron irradiation, the study of the distribution and elimination of radioactive isotopes introduced into the human body, the inspection of food- stuffs for radioactive contamination, etc. In this paper, a whole-body counter constructed at the I. V. Kurchatov Atomic Energy Institute is described. Description of the Whole-Body Counter The spectrometer is located in the basement of a four-story building with brick exterior. The spectrometer detectors and the subject to be measured are placed inside a steel chamber with internal dimensions 2 x 2x 2 m. The walls, floor, and ceiling of the chamber, which are covered on the inside by plastic sheeting, are 20 cm thick, and are made of Steel plates. The rolling door of the chamber is put into motion by an electric deive. Four de- tectors.with scintillation counters (Fig, 1) are set up in the chamber; a canvas litter, on which an individual or phantom is placed for measurement, is centered vertically in the chamber. Two detectors are located above the litter and two below it. A suspension system assures independent manual shifting and securing of each detector both in the horizontal and vertical directions. If necessary, the litter can be moved away from the detectors, or moved to a vertical position on a wall of the chamber. The chamber is ventilated by an inflow of heated air (actual flow, 300 m3/11). The air is kept free of naturally radioactive aerosols by means of high-efficiency, fine-fiber filters. Auxiliary rooms (Fig. 2) are located close to the chamber which make it possible to eliminate the chance of accumulating within the chamber accidental radio- active contamination brought in on clothing or on the body. The subject being studied, after registration and medi- cal examination, goes through a health control point, undergoes radiometric checking for cleanliness of the body surfaces, dresses in a cotton suit, and enters the chamber for measurement. The main electronic equipment (pulse 173 Declassified and Approved For Release 2013/09/24: CIA-RDP10-02196R000700010002-5 174 Declassified and Approved For Release 2013/09/24: CIA-RDP10-02196R000700010002-5 Fig. 1. Inside view of chamber with the four scintilla- tion detectors of the whole-body counter. (Sm Equipment room (15ni') AVA:VAVMVXV:Vill V Reception room (34m2) z 2"/ / Dressing Health room unit (5m 2 ) Store room) Fig. 2. Plan of spectrometer arragement and associated auxiliary rooms. Declassified and Approved For Release 2013/09/24: CIA-RDP10-02196R000700010002-5 Declassified and Approved For Release 2013/09/24: CIA-RDP10-02196R000700010002-5 Crystal Dimensions and Can and Window Materials Used in the Detectors Crystal - dimensions, mm Can material Window material diameter height 200 200 140 140 60 50 50 50 Aluminum 1Kh18N9T stainless steel Quartz Type TK-16 potassium- free glass height analyzer, distribution unit, plate-filament power supply, electromagnetic stabilizers) and instruments for checking and adjustment are located in a neighboring room. Each of the four detectors contains a scintillation counter consisting of a NaI(T1) single crystal and an FU-44 photomultiplier with an envelope of type S49-1 (3S-5-Na) potassium-free glass. The crystal cans are made of stain- less steel or aluminum; the windows are of quartz or potassium-free glass. The table gives the dimensions of the crystals installed in each detector and the materials used in cans and windows. The construction of the detectors assures minimum absorption of recorded y -radiation in the entrance window because the aluminum container which fastens the crystal to the detector covers only the lateral surfaces of the crys- tal can and has a minimal thickness of 1.5 mm. The materials from which structural elements of the detectors are made (aluminum, St. 3, Armco iron, SAV aluminum alloy) were previously investigated with respect to radioactive contamination in order to select materials with minimum specific activity. A cathode follower with 6N6P dual triodes is mounted in each detector. Signals from the output of the cathode follower, as well as high voltage for the photomultiplier and the plate- filament supply of the preamplifier, are fed by cables coming out of the ceiling of the chamber through the labaryn- thine entrance of the ventilation duct. Pulses from all detectors are summed in the distribution unit. At the same point, regulators are provided with which one can vary the high voltage supplied to the photomultipliers of each detector in order to couple them. The high voltage is taken from two VS-22 high-voltage rectifiers fed by SNE 220/0.5 electromagnetic stabilizers. VS-12 rectifiers are used for the plate-filament supply of the detector preamplifiers. The pulse height analysis is carried out with ADA-50 or AMA-3S analyzers. As a rule, the latter is kept in reserve. Studies to Improve Spectrometer Parameters The particular conditions under which a whole-body counter is used are, as already mentioned, the small amount of radioactive materials requiring identification and quantitative determination, and the large dimensions and complex geometric shape of the volume source and of the absorbing and scattering media. Thus there arises the necessity for ensuring low background and high detection efficiency for low-intensity y -radiation. It is necessary to change the location of the detectors from measurement to measurement because of the large dimensions of the human body and the possibility of a concentration of activity in individual organs. Consequently, an additional requirement is the stability of detector readings under constant conditions of irradiation. It is there- fore necessary to eliminate the effect of a magnetic field on photomultiplier operation. For the same reason, local- ized sources of increased background are not permissible in the chamber equipment or in the detectors. The complexity of the geometric shape of the subjects measured that has been mentioned makes it necessary to give up the use of point sources of known activity for calibrating the spectrometer and to calibrate either with 175 Declassified and Approved For Release 2013/09/24: CIA-RDP10-02196R000700010002-5 Declassified and Approved For Release 2013/09/24: CIA-RDP10-02196R000700010002-5 220V 0 0 ". 220/380 IT 6 Fig. 3. Electrical circuit used for demagnetization of the chamber: 1) VSA-5 rectifier; 2)type PS-500 welding unit; 3) 600 A ammeter; 4) 30 A ammeter; 5) current-reversing switch; 6) steel shielding. phantoms or with humans in whose bodies there are known amounts of radioactive materials. Because spectrometer calibration for many isotopes with a phantom is an extremely time-consuming process, instrumental stability and constancy of background counts over a period of several months are desirable. In turn, this places rigid requirements on such parameters as constancy of gain, invariance of the calibration curve for dependence of spectrometer sensitiv- ity on radiation energy, 'steady background, etc. In order to reduce the inherent detector background, studies were made of the potassium contamination in glasses and in canning materials, as well as in the raw materials for the manufacture of NaI(T1) single crystals at various stages in processing and production, and in the finished scintillators. As a result, a strong fluctuation of potassium content from batch to batch (of an order of magnitude) came to light. It was further established that, during the course of the process adopted for growing single crystals of NaI(T1), potassium from .the ceramic forms migrated into the sodium iodide melt. A satisfactory solution for the problem of reducing potassium content in finished crystals (down to 5. 10-4?70) was obtained by using quartz ampoules for growing crystals from selected raw materials. . The work on growing potassium-free crystals was carried out by members of the single-crystal scintillator laboratory of the All-Union Instrument Research Institute, and the spectral analysis of potassium content in raw materials and at various stages of the crystal production process was performed by members of the State Rare Metals Research Institute and of the Geochemical Institute, both in Moscow, to all of whom the authors take this opportunity to express their gratitude. A significant source of potassium background was detected in the glasses used in several types of photomulti- pliers and scintillators. For example, the use of a type FEU-44 photomultiplier, whose envelope is made of 3S-5-Na potassium-free glass, instead of the previously used FEU-24, in a detector with a commercial NaI(T1) scintillator 70 x 50 mm in size (potassium content ? 2. 10-2%) reduced the background counting rate by approximately 1.8 times. At the same time, the total counting rate for measured activity in the glass of the FEU-24 photocathode and in the window of the can of the single crystal mentioned was approximately 9500 and 5000 cts/h, respectively, the photopeak for K4? radiation being clearly visible in both spectra. A significant admixture of potassium is also found in the FEU-11A, FEU-13, and particularly the FEU-23 photomultipliers. In order to select materials for scintillator windows, studies were made of plastic (Plexiglas),1 quartz, and 3S-5-Na and TK-16 potassium-free glass. In none of the materials was any noticeable activity whatever detected with the exception of TK-16 glass. Measurements of the latter revealed an insignificant rise in counts, mainly in the 0.6-MeV region. Apparently, this is explained by the contamination with isotopes of the radium and barium families found in TK-16 glass. The measurements also showed that slightly active materials suitable for use inside crystal and detector cans are manganese oxide, polystyrene cement, 1Kh18N9T stainless steel, copper, aluminum, St. 3 carbon steel, Armco iron, Permalloy-78, and various synthetic materials. These materials were used in the manufacture of scintillator cans and detector components. 1NaI(T1) crystals sealed in cans with Plexiglas windows were short-lived. 176 Declassified and Approved For Release 2013/09/24: CIA-RDP10-02196R000700010002-5 Declassified and Approved For Release 2013/09/24: CIA-RDP10-02196R000700010002-5 / The most suitable photomuliplier turned out to be the FEU-44 with an envelope of 3S-5-Na potassium-free glass. As a result, the total background counting rate in the 150-2100 keV energy range per kg of scintillator was reduced to 7800 cts/h [2]. This made it possible to achieve a sensitivity of 10-9 Ci of a y-emitting isotope in the body of an individual (1.4 10-I1Ci/kg) for a counting period of 300 sec. The resolution for the 661 keV y-quanta of Cs137 was 17-21% for individual detectors and 19% for measurements with the four detectors. During tests of the electronic equipment, it was observed 40 40 40 that the main source of unstable operation was the photomulti- plier. A batch (15 samples) of type FEU-44 photomultipliers was checked by testing each sample for 24 h. After a four-hour warmup, variations in pulse height (for pulses corresponding to the CsI37 photopeak) did not exceed 1% for four of the FEU-44, were no more than 6% for four others, and were greater than 6% for the rest. Subsequent measurements were made on selected samples of stable photomultipliers during 24-h operation of the equipment. When using the FEU-44 photomultipliers, it became apparent that the pulse heights at the photomultipliers, output varied with shifts or changes in the positions of the detectors in the chamber though irradiation conditions remained the same. The same sort of an effect, although to a lesser degree, was observed with the use of FEU-24 photomultipliers. By shielding a detector with several layers of Armco iron or Permalloy, it was established that the variations in pulse height were associated with the existence of a magnetic field in the chamber which dis- torted the electron trajectories in the focussing region of the FEU-44 photomultiplier (in the FEU-24 photomultiplier, this effect was smaller because the electron trajectories in it are considerably shorter). Therefore, the magnetic shielding of the photomultipliers (Armco iron, 2 mm thick) proved to be unsatisfactory. Direct measurements with a magnetometer verified the existence of strongly inhomogeneous magnetic field inside the chamber whose instensity in particular areas exceeded values typical of the Earth's magnetic field. The maximum value of the horizontal component of the magnetic field inside the chamber was 0.8 Oe. Evidently, the existence of such a field was connected with the fact that the chamber was constructed of steel plates which very likely had previously undergone magnetization. To reduce the effect of the field on the operation of the detectors, it was decided to demagnetize the cham- ber with alternating current. To accomplish this, the multilayer steel shielding was wrapped with 20 turns of cop- per conductor 150 mm2 in cross section. The current supply was a PS-500 welding machine to whose excitation winding a VSA-5 rectifier was connected to provide current regulation (Fig. 3). The current during a single cycle was varied manually in such a way that its time variation was approximately sinusoidal. The length of a cycle was chosen to be 1 min on the basis of the reaction to the skin effect. After each cycle, the current direction was re- versed by means of a switch. The maximum current amplitude in the first cycle was 600 A; the reduction in am- plitude from cycle to cycle was 20 A. As a result of this demagnetization, the field in the chamber became uniform; the average value of the horizontal component of magnetic field intensity was reduced to 0.06 Oe. When a detector with an FEU-44 without magnetic shielding was moved around the chamber, the pulse height at the photomultiplier output underwent no variation. Fig. 4. Location of detectors for whole-body counting. Spectrometer Calibration There are several methods, differing in accuracy and principles, for calibrating the spectrometer. The first of these consists of the introduction of a known amount of radioactive isotope into the body of a control subject and the measurement of the resulting radiation. This method is the most accurate since it takes into account self-absorption and scattering of the y -radiation in the body of the particular individual. However, the introduction of radioactivity into the body is accompanied by the acquisition of an additional dose of internal radiation, which is undesirable de- spite its negligibly small amount. A second, less exact method of calibration is based on a comparison of y-ray 177 Declassified and Approved For Release 2013/09/24: CIA-RDP10-02196R000700010002-5 Declassified and Approved For Release 2013/09/24: CIA-RDP10-02196R000700010002-5 ? 4=, 1500 a) co C1.1) 1000 t.Q t)13 .0 soo \\. Et= 0,66t MeV (Ci137) 1 0 10 E =146 MeV 1 k 4 0 ) x x 0 00 3 50 Channel number Fig, 5. Analysis of a radiation spectrum for an individual dontaining 127 g potassium and 15,7 nCi Cs137 (subject 121, female): 1) spectrum of radiation from the individual; 2) difference spectrum for radiation from the individual and from a phantom containing KCI; 3) difference spedtturn for radiation from the individual and from a phantom containing KCI and Cs137. spectra from a person and from a phantom filled with a solution of one or another radioactive material of known activity. In our investigations, We used the second method, which is not accompanied by the drawback mentioned above. the phantom,. Made of plaStic, had the dirnensionS of the so-called standard man (176 cm in height, 70 kg in Weight). TwO isotopes, K40 and Cs, which are most widely distributed in people's bodies, Were chosen for cali- bration. The long-lived radioactive isotope 1 5 Cl h 2 Rn lu 1, they are extracted in 20-30 revolutions at up to 5010 efficiency; the radiation dose rate is 300-400 R/min ? m. A 100 kV external injector has been proposed for use in the industrial inspection betatron system. M. Sajdl (Institute of Plasma Physics, CSSR) read a theoretical paper on the electron capture mechanism in betatron acceleration and reported on experimental research which confirms these theoretical conclusions. In his view, electrons are formed in bunches, and in the bunching process an appreciable portion of the electrons become lost with high-frequency oscillations resulting. Contraction of the instantaneous orbits ensues as a result, and the remainder of the electrons bypass the injector. Prof. A, A. Vorob'ev (USSR) drew attention to the fact that this theory can possibly explain many experiments on electron acceptance in the acceleration mode. C. C. Ilescu (Institute of Atomic Physics, Rumania) submitted an account of a 25-MeV Rumanian betatron, The equilibrium orbit radius of the betatron is 25 cm, the pole gap aperature is 6.74 by 7,8 cm2, and n 0.75. At an injection energy of 30 keV, the radiation dose rate is 42 Rimin. The betatron is being employed, in research on the interaction between nuclei and electrons, and in nondestructive testing. L. Schmalz and E. Burger (Physics and Engineering Institute, East Germany) reported on the design of a 30-MeV betatron. Am improved Kerst injector is used in this machine. Conductors leading to the heating filament are en- closed in metal tubes fabricated together with a Wehnelt cylinder, in order to reduce the field intensity. The fila- ment and the Wehnelt cylinder form a single replaceable unit. High-loss steel was used in fabricating the elec- tromagnet, requiring a water-air cooling system to allow continuous betatron functioning for 6 h. Details in the center of the betatron poles are water-cooled, Prof. S. Nowicki (Institute of Electronics, Poland) described the design of a 30-MeVbetatron which has been in operation since 1956. The betatron generates radiation at dose rates up to 65 Rimin? m. The energy of the ac- celerated electrons is stabilized and subject to smooth control. Cold-rolled steel with a maximum induction of 17,000 G in the rolling direction and 14,000 G transverse to the rolling direction is used for the electromagnet. The vacuum chambers are made of porcelain or of epoxy resin. Prof. A. A. Vorob'ev (Tomsk Polytechnic Institute, USSR) reported on projects for developing miniaturized and high-:current betatrons, and on betatrons for nondestructive inspection of thick-walled structures under industrial 240 Declassified and Approved For Release 2013/09/24: CIA-RDP10-02196R000700010002-5 Declassified and Approved For Release 2013/09/24: CIA-RDP10-02196R000700010002-5 conditions. The miniaturized betatrons (developed under the supervision of L. M. Anan'ev) and their use in practice are subjects of keen interest. V. A. MoskaleV (Nuclear Physics Research Institute, Tomsk Polytechnic Institute, USSR) reported on the de- velopment of high-current dual-chamber stereobetatrons and betatrons for physical research. As many as 1012 elec- trons are accelerated to 25 MeV in a pulsed stereobetatron by increasing the gap aperture of the electromagnet (220 by 290 mm) and by high-voltage external injection (350 kV). The intensity of the 25-MeV betatron no.w being manufactured, operating at 50 cps, is 780 R/min?m even at 15 MeV, and should be several times higher when the machine is brought up to its full energy rating. A high-current bantam-size 3 MeV stereobetatron is designed to operate at frequencies to 1000 cps. Its magnet is wound from thin-sheet cold-rolled steel. It is suggested that its intensity will be about 10 R/min?m, with each accelerating system in the stereobetatron operating at the frequency 400 cps. M. F. Filippov (Tomsk Polytechnic Institute, USSR) reported on engineering calculations procedures for de- signing a betatron electromagnet and for optimizing chamber dimensions in terms of a specified energy and speci- fied dose rate, V. A. Vorob'ev (Tomsk Polytechnic Institute, USSR) reported on applications of bantam-size 3-5 MeV beta- trons for inspection of seam weldments under industrial conditions, and also reported on variations in absorption. The reporter suggested an approach for calculating the sensitivity of radiation flaw detection techniques in hetero- geneous materials, W. Polit (Institute of Biophysics, West Germany) reported on techniques for measuring the intensity and energy of y -radiation. The design of calorimeters, flow-type and extrapolating ionization chambers facilitating absolute measurements of both intensity and energy of y -radiation, was described. A paper by F. Klapper (Physics and Engineering Institute, German Democratic Republic) was devoted to mea- surements of y-radiation intensity at energies from 7 to 30 MeV, using a thick-walled chamber. The energy de- pendence of the chamber current over the 7 to 30 MeV energy range was shown to remain within 110 variation when the walls of the ionization chamber are 4,5 mm thick. J. Slaba (Materials and Production Technology Research Institute, CSSR), I. Leibovici (Institute of Atomic Energy, Rumania), G. Nietzsche (Physics and Engineering Institute, German Democratic Republic), F. Klapper (Physics and Engineering Institute, German Democratic Republic) devoted their reports to betatron nondestructive inspection of thick-walled stuctures and parts. J. Slaba reported that on the development of contrast-enhancement screens of monolayer films of fluorescent material coated on metal to improve the productivity and sensitivity of betatron radiographic techniques. Because of the minute thickness of this screen, the sharpness of the resulting image is far greater than when screens on a cardboard substrate are used. The report by G. Nietzsche told of the first work in the field of betatron radioscopic flaw detection under- taken at the Physics and Engineering Institute. The use of contrast-enhancing screens made of tantalum was found to be less expensive because of the long service life of the screens. When the betatron intensity was stepped up from 80 to 140 R/min, thick-walled parts could be inspected with acceptable exposures. The paper by I. Leibovici reported on the reduction in size of the focal spot when a protruding target was employed. Prof. R. Widerbe reported that the Brown-Boveri Ltd. firm has delivered 31 medical betatrons to various coun- tries throughout the world (USA, Japan, Italy, the Netherlands, West Germany, United Kingdom, etc.). These be- tatrons produce a beam of y-radiation or an extracted electron beam; they are equipped with a 90-100 kV diag- nostic x-ray tube. The firm delivered seven betatrons for industrial flaw inspection (the USSR was customer for one of these). Impregnated tungsten cathodes capable of generating emission currents of 250-300 A at a tempera- ture of 1050-1080?C and capable of long service life are being used as a new feature in betatron injectors; some of the cathodes have already been through 23,000 h of operational service each. Prof. P. Winderoe feels that radioactive radiation sources must be replaced by the miniaturized betatrons, since about 3000 isotopes have been used in West Germany alone during the past half decade. W. Polit, in reporting some of the results of treatment of patients by betatron irradiation, noted an important psychological factor to be taken into account in the therapy, in addition to the high penetrating power of the be- tatron y-radiation, the low scattering outside the collimating beam, etc. This psychological factor consists in the 241 Declassified and Approved For Release 2013/09/24: CIA-RDP10-02196R000700010002-5 Declassified and Approved For Release 2013/09/24: CIA-RDP10-02196R000700010002-5 freedom from radiation sickness symptoms (nausea, vomiting, headaches) which unfailingly accompany x-ray therapy, but which do not plague betatron irradiation therapy. The fact that the patients are readily willing to undergo treat- ment improves the chances for success. Polit reported that seven betatrons of energies randing from 10 to 50 MeV are in operation in various West German cities, in experiments following a single master plan. All of the labora- tories share a common system of accident prevention and maintenance provided for by the supplier. The colloquium revealed a high demand for betatrons; the main problem now is simplification of operating procedures and improvements in the intensity and reliability of the machines. Mention was made of the unfeasability of raising the electron energy above 30 MeV. A decision was made to convoke the colloquium annually in one of the nations participating regularly in the Jena colloquium. The colloquium demonstrated in life the creative contact of the socialist countries in the field of research and development work on induction accelerators. Representatives of all the socialist countries engaged in work on betatrons, with the exeption of the USSR, were included on the staff of the organizing committee of the colloquium (as in the case of the two preceding colloquia). Our feeling is that an official participation by the USSR in this organizing work would have been desirable. 242 Declassified and Approved For Release 2013/09/24: CIA-RDP10-02196R000700010002-5 Declassified and Approved For Release 2013/09/24: CIA-RDP10-02196R000700010002-5 CONFERENCE ON THE PHYSICS AND TECHNOLOGY OF ALKALI HALIDE SCINTILLATORS R. V. Bakradze and Yu. A. Tsirlin Translated from Atomnaya gnergiya, Vol. 18, No. 2, pp. 193-194, February, 1965 The April 1964 conference on the physics and technology of alkali halide scintillators was held at the All- Union Single Crystal Research Institute in Khar'kov. The purpose of the conference was to seek out ways to im- prove the scintillation efficiency and resolving power of alkali halide single crystals. E. R. Il'mes et al., (Institute of Physics and Astronomy?Academy of Sciences of the Estonian SSR) submitted a report "Mechanism of photoluminescence and radioluminescence in ionic crystals" pointing out how the scintil- lation efficiencies achieved at present in the USSR and elsewhere fall below the theoretical estimates (see Table 1), The reason for this appalingly low scintillation efficiency is said to be large inertial losses and partly migra- tion losses. A. B. Lyskovich (L'vov State University) reported on a study of the effect of etching quality in growing NaI(T1) crystals by the Kiropoulos method. A correlation was established between the resolving power of the crystals and the slow component in scintillation quenching. The results confirmed the dual (exciton and electron-hole) mechanism of energy transfer in NaI(T1). A paper presented by K. K. Shvarts and E. D. Aluker (Institute of Physics of the Academy of Sciences of the Latvian SSR) cited data on the radioluminescence of thallium-activated KCI, KBr, KI, Nal, CsI crystals excited by y-x-ray bombardment and in-pile radiation. The thermoluminescence spectra, the temperature dependence of the steady-state luminescence in excitation by x-radiation and y-radiation, by a-particles and by pile radiation, were studied. The temperature dependence of the radioluminescence yield was found to deviate markedly from the tem- perature dependence of the yield of luminescence within the impurity centers. Differences were also found in the behavior of the yields for the fast and inertial components of radioluminescence. The variation of the luminescent yield with temperature differs substantially as dE/dx varies (e. g., in the case of a-radiation and y-radiation). Even though the detailed mechanism underlying the temperature quenching process remains obscure, experimental data indicate that quenching of radioluminescence leads primarily to radiationless electron-hole recombination, i. e., to external quenching processes. Findings of a study on thermal and thermo-optical de-excitation and on excited absorption of NaI(T1) crystals exposed to x-rays were reported in a paper by Z. B. Baturicheva (Single Crystal Research Institute). Diminished absorption of paired thallium activator centers (>max 310 mg) following x-ray treatment was reported, with the ? absorption recovered exponentially with a period of 3 min. Redistribution of electrons over trapping levels (F cen- ters and thallium centers) as a result of plastic flow and changes in thallium concentration was also considered. TABLE 1. Radioluminescent Efficiency of Alkali Halides Substance Radioluminescent efficiency, lo experimental theoretical KI(TI) UI(Tl) 'MI(H) 31 25 33 (i 15 The reporter found a number of glow peaks due to breakdown of the trapping centers, which are as- sociated with thermal microimperfections in the lat- tices. The proposition was advanced that the large light sums stored in certain crystals are due to the presence of impurities in those crystals, and parti- cularly to the presence of anion impurities. A report by A. N. Panova (Single Cryatal Re- search Institute) was devoted to an investigation of the excitation spectra and kinetic behavior of NaI(T1) single crystals containing both cationic and anionic 243 Declassified and Approved For Release 2013/09/24: CIA-RDP10-02196R000700010002-5 Declassified and Approved For Release 2013/09/24: CIA-RDP10-02196R000700010002-5 impurities. The presence of copper and of anionic impurities appearing in the crystal during the growth phase was found to lower the luminescent yield in the absorption region of the host material by recombination losses. Lead impurity introduced into the crystal, principally with the activator, was also found to reduce the luminescent yield, both by competition in the absorption of the exciting radiation and by reabsorption of thallium emission. The con- clusion was reached that the inertial response and the ratio of the excitation in the lattice to the excitation in the long-wavelength activator band may be used to estimate the quality of the scintillator crystals (homogeneity through- out the volume, freedom from impurities). A paper by Ya. A. Zakharin provided a review of the research conducted at the All-Union Single Crystal Re- search Institute on the development of a fabrication technology for variously dimensioned NaI(T1) crystals of spec- trometric purity. The significance of the quality of the raw material and of the preparation techniques prior to crystal growing was demonstrated. The best specimens of NaI(T1) crystals 150 mm in diameter featured 10-11% resolution (over the Cs137 y-ray photopeak). A paper by T. A. Soovik, N. E. Lushchik, Ch. B. Lushchik contained the results of research by the Institute of Physics and Astronomy of the Academy of Sciences of the Estonian SSR on surface activation of alkali halides in or- der to produce scintillation detectors. Problems related to the production of raw material for scintillators and to their fabrication technology were also discussed at the conference. 244 Declassified and Approved For Release 2013/09/24: CIA-RDP10-02196R000700010002-5 Declassified and Approved For Release 2013/09/24: CIA-RDP10-02196R000700010002-5 "ATOMIC ENERGY" PAVILION AT THE 1964 EXHIBIT OF ACHIEVEMENTS OF THE USSR NATIONAL ECONOMY L. I. Petrenko Translated from Atomnaya Energiya, Vol. 18, No. 2, pp. 194-197, February, 1965 The "Atomic Energy" pavilion at the exhibit of the achievements of the USSR national economy underwent substantial rearrangement and renovation in 1964, and was housed in a new building. Approximately 130 research, design, and civil engineering organizations, industrial plants, educational insti- tutions, and medical institutions demonstrated their achievements in the "Atomic Energy" pavilion, in over 550 exhibits. The pavilion was opened to the public with a display of results achieved in the development of nuclear power and controlled fusion research. The public showed special interest in models of the I. V. Kurchatov nuclear power station at Belyi Yar and the nuclear power station at Novyi Voronezh, the OGRA, OREKH, TOKAMAK, and PR-5 thermonuclear machines, and the nuclear-powered icebreaker LENIN. Color film shorts on the work of Soviet re- search scientists in the promotion of nuclear power and plasma research, and film shorts on the navigation of the nuclear vessel LENIN were shown. Moving color displays presented the visting public with an opportunity to acquaint themselves with the operating principles of nuclear electric power stations, and exhibits of designs of fuel elements and various materials used in nuclear reactor construction and design provided a lucid picture of the com- plexity of the problems resolved by our scientists and engineers. The adjoining hall showed the results of work in building unique accelerator facilities intended for the study of the structure of the atomic nucleus and for the production of new transuraniuni elements. Models of accelerators built at the Joint Institute for Nuclear Research are on display here (the 10-GeV proton synchrotron, the multiply- charged ion accelerator, and others), as well as machines in operation at other research centers. Excellent display stands give the public an idea of the scope of the construction work on the world's largest accelerator in the Serpu- khov district?a 60-70 GeV strong-focusing proton synchrotron. Here the public becomes acquainted with the principles for recording nuclear radiations, and with a wide ? ? variety of radiation detectors manufactured for that purpose by our industry. Gas discharge counters, scintillation crystals and plastics, photoelectric multiplier tubes on exhibit were indicative of the unyielding growth and advance- ment of this new field in scientific instrumentation. The accompanying table cited technical data on some of the photomultiplier tubes which the visitors displayed peak interest in. A considerable portion of the exhibit in the pavilion was devoted to methods in the use of nuclear radiations, stable and radioactive isotopes in various branches of the national economy, and in the production of isotopes. This section took up about half the entire floor area of the pavilion, and was opended by a stand display showing the USSR isotope production picture. Visitors manifested keen interest in models of research reactors such as the VVR, IRT, and SM-2 piles, and in exhibits demonstrating the possible uses of nuclear radiations in radiation processing of materials and in radiation chemical processes. Findings of research on radiation modification of cotton, radiation processing of polyethylene cable insulation, thermoradiation vulcanization of rubber tires, were presented to the public here. Industrial en- terprises in such districts of the national economy as the Western Siberian, Donets basin, L'vov, Volgo-Vyatsk, Byelorussian, and others demonstrated their achivements on incorporating isotope techniques in industry. Radioisotope studies of special aspects of the process of reduction of phosphorus pig iron melts and high-load- capacity tilting open hearth furnaces, and tracer studies of wear on the hearths, have been carried out at the Sergo Ordzhonikidze "Azovstal" Zhdanovo metallurgical plant; these studies have resulted in anew improved technology for maintenance and overhaul of the furnace hearths. 245 Declassified and Approved For Release 2013/09/24: CIA-RDP10-02196R000700010002-5 Declassified and Approved For Release 2013/09/24: CIA-RDP10-02196R000700010002-5 TABLE 1, Engineering Data on Some Photomultiplier Tubes Engineering characteristic FEIJ-49-B FEU-52 Design Photocathode material Diameter of effective photocathode area, mm Number of amplifying stages Electron focusing Spectral. sensitivity range, A Wavelength correspond- ing to maximum spec- tral response, A Peak height, mm Peak diameter, mm Largest weight, g Number of base pins Minimum integrated sensitivity of photo- cathode, Dark current, 10-8 A Cs137 peak amplitude reolution, % Time resolution (not inferior to), 10-8 Peak supply voltage, V Ambient temperature, ?C *As in Russian original-- Glass Glass, baseless Antimony-potassium- sodium -cesium, semi- transparent, on inner side of envelope 150 12 3000-8000 203 171 1000 35 80 3000 + 70 = 60 Publisher. 70 12 2000-8000 4200 ? 500 133,3 81 180 20 50 6 < 14 6 2500 + 70 ? 60 FEU-53 FEU-54 FEU-55 FEU-56 Glass, baseless Glass, baseless with hard or soft lead-in wires Glass, baseless with hard Or soft lead-in wires Bismuth- silver-cesium, semi= transparent Glass, baseless Antimony- cesium, semi- transparent Antimony-cesium, semitransparent 45 16 16 70 14 14 14 12 Electrostatic, alloyed louvers 2500-6500 4200 ? 200 117 3300-6500 4000-100 - 200* 90 3300-7500 5000 ? 200 90 3000-6500 4000 ? 200 133.3 51 21.5 21,5 81 120 25 25 180 20 22 22 20 25 20 20 30 < 10 < 80 < 80 < 10 < 12 .< 13 ? 2 < 14 6 2500 + 70 ? 60 1800 + 85 ? 60 1800 + 85 ? 60 6 2500 + '70 ? 60 The Luga isotopes laboratory has carried out extensive work to promote the use of radioisotope devices and means in automatic process monitoring and control in that region. A y-ray inspection method for monitoring joints in rubber conveyor belting buttressed by steel lines has been installed at the Novo-Druzheskii mine pits, thereby aiding in the organization of timely preventive maintenance and bringing about savings of 25 thousand rubles an- nually by eliminating teats in the belts. y-ray electronic switches for monitoring fill levels in dumpcars, automa- tion of skip hoist operation, automatic filling of wheelbarrows and automation of other processes in loading, un- loading, and hauling of coal are being used at the Talovskaya-2, Artem No. 10, Krasnyi Partizan, and other mines, thereby freeing a certain number of miners from underground duties. At the Angara oil refinery in the Eastern Siberian district of the national economy, the introduction of radio- isotope instrumentation has meant significant improvements in production and working conditions at absorption plants, thermal cracking plants, and in apparatus where corrosive materials are used. 246 Declassified and Approved For Release 2013/09/24: CIA-RDP10-02196R000700010002-5 Declassified and Approved For Release 2013/09/24: CIA-RDP10-02196R000700010002-5 Annual savings not less than 40 thousand rubbles have been achieved at the State Razdol'skii Ore chemical processing combine via improvements in sulfur technology resulting from the implementation or radioisotope instru- ment techniques. A display sponsored by the Il'ich Zhdanovo metallurgical plant was quite popular; this stand showed the orga- nization of radioisotope work for process monitoring and research. A special class II radiometric laboratory was set up, equipped for work with unsealed radioactive isotopes. Four teams are working in this laboratory on electronics and radiometry, on blast furnace and steelmaking production, on steel rolling and allied production, and on radia- tion safety. Staff members of the laboratory are principally engaged in the study of metallurgical production pro- cesses using radioactive tracers, and in the development and implementation of automatic control plans involving the use of commercial radioisotope instrumentation. The servicing and operation of radioisotope instruments in- stalled in production premises are carried out by a special division of the instrument and measurement workshop. The radiation safety team is responsible for the systematic checking and supervision of the proper use and implemen- tation of radioisotope techniques, for elaborating instructions on safe work practices, for indoctrinating servicing and maintenance personnel in the basics of work with radioactive materials. Radiation safety posts headed by lead- ing laboratory technologists have been set up in those shops of the plant where radioisotopes are in general use (the blast furnace section, the steelmaking section, the rolling mill section). The electronics and radiometry team and the radiation safety team are headed by engineering physicists, while the team responsible for radioactive tech- niques in blast furnace, steelmaking, and rolling mill production are engineering technologists in the specialties involved. Stands demonstrating the predominant use of radiation sources and isotopes in the prospecting, exploration, and development of mining ores are well designed and equipped; the work of the All-Union Institute of Nuclear Geophysics and Geochemistry and the "Tatneftegeofizika" petroleum geophysical trust, and others is represented in the display. Among the instruments on display is a variety of isotope equipment for process control and monitoring and special-function instruments, The IGN-1 pulsed borehole neutron generator designed to aid in the study of the actual composition of rocks encountered in prospecting and exploration work at ore deposits is an original design, and is used in pulsed neutron-neutron logging work in boreholes over 127 mm in diameter and down to 3000 meters in depth. This is a reliable instrument for tracking down displacements in water-oil and gas-liquid contacts in strata, and is a tremendously useful tool in monitoring the development of oil and gas fields, and in reducing loss of pay ores. A miniaturized ion accelerator in which fast 14 MeV neutrons are formed by bombarding a tritium target with up to 0.3 MeV deuterons, is employed as the neutron source; the average yield of fast neutrons is 5. 107 neutrons/sec; the pulse rate is 200 Hz with pulse duration from 50 to 200 msec. Slow neutrons are recorded by means of propor- tional counters filled with boron trifluoride. The diameter of the well drilling rig is 102 mm, and the length is 2900 mm. Visitors manifested special interest in the SDPU-1 smoke and fire alarm system; it is designed for remote detection of smoke from a conflagration, and may also be used as an alarm device for overheating or hot spots in electrical equipment and as a sensor for actuating fire-dousing equipment. The device operates on the basis of the difference in the ionization brought about by a-particles emitted by the isotope Pu239 in pure air and in smoke- filled air. The facility features 100 distinct sensors which may be stationed in different rooms, and serves to monitor an area of about 10,000 m2. The facility is supplied from a 220 V ac supply, consuming 80 W power. This section is completed with a display on applications of nuclear radiations and isotopes in construction, biology, agriculture, and medicine. The Institute of Experimental Biology of the Academy of Sciences of the Uzbek SSR presented the results of the derivation of new strains of the cotton plant by radiation-induced selection experiments. Two new strains of cotton featuring distinct advantages over their precursors were obtained. One of these is distinguished by larger bolls weighing 9 to 9,5 g, and by an increase in the number of bolls, to 11 bolls on a single plant. The second strain produced had smaller bolls (0-7-1 g less than in the parent strain), but yielded a very slender silken fiber. Substantial changes have been brought about in the outfitting of medical institutions in recent years, with the use of nuclear radiation and radioisotopes in the therapy and diagnostics of a variety of illnesses and malfunc- tions, and this was properly reflected in the exhibit at the pavilion. The Semashko Central Clinical Hospital de- monstrated techniques for utilizing P32 in the treatment of erythremia, a blood disease. Small doses of radioactive phosphorus were introduced over a 5-7 day interval, to make up a total dosage of 8 mCi. Normalization of the state 247 Declassified and Approved For Release 2013/09/24: CIA-RDP10-02196R000700010002-5 Declassified and Approved For Release 2013/09/24: CIA-RDP10-02196R000700010002-5 BIBLIOGRAPHY NEW BOOKS Translated from Atomnaya nergiya, Vol. 18, No. 2, pp, 198-200, February, 1965 A. M. Kabakchi, Ya. I. Lavren.tovich, and V. V. Pen'kovskii. Khimicheskaya dozim- etriya ioniziruyushchikh izluchenii [Chemical dosimetry of ionizing radiations]. Kiev, published by the Academy of Sciences of the Ukrainian SSR, 1964, 156 pages, 65 kopeks. This compact item, written by prominent Soviet research scientists, consists of four chapters and a short in- troduction. The concise first chapter (16 pages) presents a clear outline of the field of applications of chemical dosimetry techniques. The next chapter (30 pages) carries a description of the fundamentals of chemical dosim- etry. Radiation similitude of the medium investigation and of the dosimetric system, dependence of the radiation yield on various factors are presented in compact format, and a description is given of the techniques employed in recording chemical changes in dosimetric systems, with formulations of the basic requirements regarding radiation chemical reactions exploited in dosimetry. The highpoint of the book is chapter III (63 papers) which is devoted to chemical dosimetry techniques. Here the authors report information on the three.basic types of radiation chem- ical systems; aqueous solutions and gels; polymers and organic compounds; glasses and ionic crystals. The elec- trochemical method for dose rate determinations is also described briefly in this chapter. The last chapter takes up dose determinations of several modes of radiation by chemical methods. Each of the chapters features an extensive bibliography, and the total number of references runs to 435titles. The book is intended for a broad readership of specialists engaged in measurements of the absorbed energy of various types of ionizing radiations. Directory of Nuclear Reactors. Volume 5, Research, Test and Experimental Reactors [in English]. Vienna, IAEA, 1964, 327 pages. The International Atomic Energy Agency has now issued the scheduled fifth volume of the reference series on nuclear reactors, this one serving as a supplement to the second and third volumes. Volume 5 cites reference information on 78 research, testing, and experimental reactors in operation or under construction in 16 countries. As is the case in the preceding volumes, the reactors are grouped, principally by the type of moderator used. Two such groups are formed by reactors using ordinary water as moderator. The first group includes pool type research reactors; OWR, SPR, WPIR, UWNP, HHLP, PRPR, Buffalo, TR-1, IRT (Sofiya), SPERT-4, TRR-1, Siloe, Siloetta, and the IISNR reactor. Of greatest interest in this group is the French 15 MW Siloe reactor, and the uni- que SPERT-4 reactor (USA) built for research on reactor kinetics and reactor stability. The second group is formed by pressure-vessel type research reactors. These are mostly high-power modern reactors intended for nuclear engineering research: tests of fuel compositions, tests of fuel elements, controls, struc- tural materials, and reactor parts. The reactors are also designed for isotope production and physics research. Worthy of mention in the reactors of this group are the improved test reactor ATR (250 MW power rating), the ETR engineer- ing tests reactor (175 MW), the WTR (60 MeV), NASA-TR (60 MeV), and the Pegasus (30 MW) reactors. The ESADA nuclear superheat Vallecitos reactor and the HFIR high-flux reactor for isotope production, engineerin g and physics research are of enormous interest, This group also includes the NASA-MUR, Peggy, and SAFARI-1 (20 MW)reactors. The next group is constituted by the now quite popular ARGONAUT family of reactors. In most cases these are low-power reactors (from 10 to 10 kW) with light water as both moderator and coolant. They are designed for training purposes and for nuclear physics research, Of the 17 reactors in this group, many are the property of uni- versities and other educational bodies. The fourth group combines two types of homogeneous research reactors. These include six pulsed TRIGA-2 in regular production, designed for prolonged operation at 200 kW power. Peak pulsed power is 250 MW. The second 249 Declassified and Approved For Release 2013/09/24: CIA-RDP10-02196R00070001 onn9_ MEM Declassified and Approved For Release 2013/09/24: CIA-RDP10-02196R000700010002-5 of health of most patients so afflicted in the hospital was the result of this treatment, the blood composition being normalized for a 5-y period, after which the treatment is to be repeated, 209 patients have undergone this treat- ment in 12 y at the hospital, and the rate of recovery is 9250. The results of using Cr31 tracer to measure the vol- ume of blood circulating through the organism as well as, the mass of circulating erythrocytes, and the use of Fe59 to estimate the activity of blood formation and to determine the causes of spleen enlargement were other applica- tions displayed. The Moscow municipal oncological hospital No. 62 had a display on the treatment of malignant tumors by radiative therapy combined with other familar techniques. New equipment for use in the treatment of various malignancies was on display, including models of a medi- cal accelerator, a medical betatron, and the y-therapeutic ROKUS facility. The rotary-convergent y-therapeutic ROKUS facility is built for convergent, pendulum type, rotary-convergent, tangential, and static y-ray therapy of superficial and deeply embedded tumors. The radiation source employed is radioactive cobalt of up to 4000 Ci activity. The lesioned organs are treated by several fields of irradiation which are designed to minimize damage to unaffected tissues. The dose rate at one meter from the source is 60 R/min. Other new pieces of equipment being introduced into our medical institutions are the diagnostic scintillation facility DSU-61 for making scans of the 1131 in the human organism, and the general-purpose 8-probe KOMETA radiometer for localizing malignant tumors by recording the P32 accumulated in them, and for intracavitary and skin examinations. The pavilion displayed instruments and equipment used in radiation safety and health physics work, including remote-control devices, auxiliary equipment, instrument kits and materials for safe handling of radioactive isotopes and nuclear radiation sources. Visitors were familiarized with documents attesting to the international cooperation of the USSR in the field of peaceful uses of atomic energy, and with literature published by ATOMIZDAT. Many of the organizations which put up displays in the "Atomic Energy" pavilion were awarded diplomas by the administration of the Exhibit. Among these were the I. V. Kurchatov Institute of Atomic Energy, the Power Physics Institute, the Institute of Theoretical and Experimental Physics, the D. V. Efremov Electronics and Physics Instruments Research Institute, the Moscow Design Institute, the Union Instrument Design Research Institute, the Joint Institute for Nuclear Research, the All-Union Institute of Nuclear Geophysica snd Geochemistry, the V. I. Lenin Nevskii Machine Tool Factory, the Shcherbakov Moscow Silk Combine, the Moscow Vacuum Tube Plant, the All- Union Research Institute for Medical Instruments and Equipment, the Radiological Division of the Moscow Municipal Clinical Hospital No. 40, the Moscow Research Institute for Safe Work Practices in the Coal Industry, and many others. The staff members of these institutions who took an active part in the development, design, and implemen- tation of radiation techniques were awarded with medals and monetary prizes. In addition to the main exhibit, the pavilion systematically organizes topical exhibits devoted to specific aspects of the use of atomic energy, which are accompanied by .a discussion of the most important displays pre- sented to the public and by an extensive exchange of experience. 248 Declassified and Approved For Release 2013/09/24: CIA-RDP10-02196R000700010002-5 Declassified and Approved For Release 2013/09/24: CIA-RDP10-02196R000700010002-5 BIBLIOGRAPHY NEW BOOKS Translated from Atomnaya nergiya, Vol. 18, No. 2, pp. 198-200, February, 1965 A. M. Kabakchi, Ya. I. Lavrentovich, and V. V. Pen'kovskii. Khimicheskaya dozim- etriya ioniziruyushchikh izluchenii [Chemical dosimetry of ionizing radiations]. Kiev, published by the Academy of Sciences of the Ukrainian SSR, 1964, 156 pages, 65 kopeks. This compact item, written by prominent Soviet research scientists, consists of four chapters and a short in- troduction. The concise first chapter (16 pages) presents a clear outline of the field of applications of chemical dosimetry techniques. The next chapter (30 pages) carries a description of the fundamentals of chemical dosini' etry. Radiation similitude of the medium investigation and of the dosimetric system, dependence of the radiation yield on various factors are presented in compact format, and a description is given of the techniques employed in recording chemical changes in dosimetric systems, with formulations of the basic requirements regarding radiation chemical reactions exploited in dosimetry. The highpoint of the book is chapter III (63 papers) which is devoted to chemical dosimetry techniques. Here the authors report information on the three,basic types of radiation chem- ical systems: aqueous solutions and gels; polymers and organic compounds; glasses and ionic crystals. The elec- trochemical method for dose rate determinations is also described briefly in this chapter. The last chapter takes up dose determinations of several modes of radiation by chemical methods. Each of the chapters features an extensive bibliography, and the total number of references runs to 435 titles. The book is intended for a broad readership of specialists engaged in measurements of the absorbed energy of various types of ionizing radiations. Directory of Nuclear Reactors. Volume 5, Research, Test and Experimental Reactors [in English]. Vienna, IAEA, 1964, 327 pages. The International Atomic Energy Agency has now issued the scheduled fifth volume of the reference series on nuclear reactors, this one serving as a supplement to the second and third volumes. Volume 5 cites reference information on 78 research, testing, and experimental reactors in operation or under construction in 16 countries. As is the case in the preceding volumes, the reactors are grouped, principally by the type of moderator used. Two such groups are formed by reactors using ordinary water as moderator. The first group includes pool type research reactors: OWR, SPR, WPIR, UWNP, HHLP, PRPR, Buffalo, TR-1, IRT (Sofiya), SPERT-4, TRR-1, Siloe, Siloetta, and the IISNR reactor. Of greatest interest in this group is the French 15 MW Siloe reactor, and the uni- que SPERT-4 reactor (USA) built for research on reactor kinetics and reactor stability. The second group is formed by pressure-vessel type research reactors. These are mostly high-power modern reactors intended for nuclear engineering research: tests of fuel compositions, tests of fuel elements, controls, struc- tural materials, and reactor parts. The reactors are also designed for isotope production and physics research. Worthy of mention in the reactors of this group are the improved test reactor ATR (250 MW power rating), the ETR engineer- ing tests reactor (175 MW), the WTR (60 MeV), NASA-TR (60 MeV), and the Pegasus (30 MW) reactors. The ESADA nuclear superheat Vallecitos reactor and the HEIR high-flux reactor for isotope production, engineerin g and physics research are of enormous interest. This group also includes the NASA-MUR, Peggy, and SAFARI-1 (20 MW)reactors. The next group is constituted by the now quite popular ARGONAUT family of reactors. In most cases these are low-power reactors (from 10 to 10 kW) with light water as both moderator and coolant. They are designed for training purposes and for nuclear physics research. Of the 17 reactors in this group, many are the property of uni- versities and other educational bodies. The fourth group combines two types of homogeneous research reactors. These include six pulsed TRIGA-2 in regular production, designed for prolonged operation at 200 kW power. Peak pulsed power is 250 MW. The second 249 Declassified and Approved For Release 2013/09/24: CIA-RDP10-02196R000700010002-5 Declassified and Approved For Release 2013/09/24: CIA-RDP10-02196R000700010002-5 type includes the very-low-power training reactors (0.1 W) manufactured by the West German Siemens-Schukkkert- werke firm, reactors which require no cooling. Both the TRIGA line of reactors and the four West German reactors belong to educational institutions. Aside from training of specialists, the TRIGA reactors were also designed for re- search on neutron physics, reactor physics, and for isotope production. Of special interest in this group is the EBOR experimental high-temperature gas-cooled reactor using beryllia moderator. It is manufactured in the USA for engineering tests and for the study of the operating characteristics of its type. The fifth group consists of 11 heavy-water-moderated research reactors. These are all pressure-vessel type reactors. The reactors NORA, ZED-2, DAPENE, and PDP, of several hundred watts power rating, are designed solely for physics research. The remaining reactors in this group feature power ratings from 5 to 60 MW and are designed - for a broader range of applications. Especially interesting among these are the HWCTR (61 MW) reactor for com- prehensive testing of fuel elements, materials, and parts; the HFBR reactor for neutron physics research and solid state physics studies, and the Haller' reactor built in Norway for the study of the dynamics and miscellaneous char- acteristics of boiling heavy-water reactors. Characteristics of graphite-moderated research reactors are cited under the next heading; GLEEP, Zenith, RB-1, and HECTOR. The most interesting reactors in this group are however the experimental and testing reactors: the high-temperature gas-cooled Dragon reactor, 20 MW, the ultrahigh-temperature UHTREX reactor (1320?C helium temperature at the reactor exit) which has been in operation since October 1964, and the original- design MSRE reactor in which fluoride salt melts are used as nuclear fuel and coolant. These reactors are designed to verify engineering solutions, and for investigation and demonstration of the power capabilities of future reactors. The concluding group encompasses seven fast research reactors: EBR-1, AFSR, LAMPRE, VERA, HPRR, Zebra, and Mazurka. Most of these reactors are being used for physics research associated with further development of fast reactors. The LAMPRE reactor burning liquid-metal plutonium fuel should be singled out here. The following information is presented for each reactor in the handbook; the over-all characteristics and purpose of the reactor, data on reactor physics, core characteristics, fuel element specifications, data on the reactor control system, fuel element design, design of other important parts (pressure vessel, reflector, shielding, etc.), data on in-core heat transfer, costs, experimental reactor equipment. This handbook will prove highly valuable to a broad range of specialists, the more so in that the last publi- cation of a handbook on research reactors (Vol. 3 in this series) appeared as far back as 1960. In addition, one should not fail to note the unfortunate timing of the publication of this volume, i. e., on the eve of the third Geneva UN conference on the peaceful uses of atomic energy, a circumstance which prevented the compilers from supple- menting the handbook with data on new research reactors and testing reactors made available at the Geneva conference. Radiation Chemistry. Proceedings of the Tihany symposium. Budapest, published by Publishing House of the Hungarian Academy of Sciences, 1964 [in English], 482 pages. A detailed report on the symposium may be found in this journal, Atomnaya energiya 14, 595 (1963). The book will be found useful by scientific workers engaged in research in the field of radiation chemistry. 250 Declassified and Approved For Release 2013/09/24: CIA-RDP10-02196R000700010002-5 Declassified and Approved For Release 2013/09/24: CIA-RDP10-02196R000700010002-5 C) lzy. AN SSSR 0(td). Kh(im). N(auk) lzv. AN SSSR 0(td). T(ekhn). N(auk): Metall). i top. fzy. AN SSSR Ser. fiz(ich). lzv. AN SSSR Ser. geofiz. lzv. AN SSSR Ser. geol. lz. Vyssh. Uch. Zav., Tekh. Teks. Prom. Kauch. i rez. Kolloidn. zh(urn). Metallov. i term. Met. i top.(gorn.) Mikrobiol. OS, Opt. i spektr. Paleontol. Zh(urn) Pribory i tekhn. eks(perimenta) .Prikl. matem. i mekh(an). PTE Radiotekh. Radiotekhn. i elektron(ika) Stek. i keram. Svaroch. proiz-vo Teor. veroyat. i prim. Tsvet. metally UFN UKh, Usp. khimi UMN Vest. mashinostroeniya Vop. onk(o1). Zav(odsk). lab(oratoriya) ZhAKh, Zh. anal(it). Khim(ii` ZhETF Zh. eksperim. i teor. fiz. ZhFKh Zh. fiz. khimii ZhNKh . Zh. neorg(an). khim. ZhOKh. Zh. obshch. khim. ZhPKh Zh. prikl. khim. ZhSKh Zh. strukt(urnoi) khim. ZhTF Zh. tekhn. fiz. Zh. vyssh. nervn. deyat. (im. 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National Institutes of Health** 16 18 7 23 4 18 1 14 2 6 26 25 6 53 2 4 3 22 4 16 " 6 19 30 13 5 1 33 66 29 15 39 7 24 7 28 33 4 19 23 1 26 1 11 1 3 1 1 1 3 1 8 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 4 1 1 1 1 4 1 1 1 1 7 1 1 1 1 1 1 1 1952 1954 1957 1958 1960 1959 1960 1959 1952 1957 1958 1957 1960 1957 1960 1959 1962 1958 1962 1959 1958 1958 1958 1962 1961 1961 1959 1959 1956 1959 1956 1960 1958 1960 1960 1959 1961 1958 1952 1955 1959 1959 1949 1950 1960 1956 1962 1961 *Sponsoring organization. Translation published by Consultants Bureau. **Sponsoring organization. Translation published by Scripta Technica. Declassified and Approved For Release 2013/09/24: CIA-RDP10-02196R000700010002-5 Declassified and Approved For Release 2013/09/24: CIA-RDP10-02196R000700010002-5 f 1 \ ? RUSSIAN TO ENGLISH sclootist-traoslator mot 0 .You can keep abreast of the latest SOViet research 4 in yourfield while supplementing your inCome1?y, translating in your own home on a pare-titne basis. In the expanding Consultants Bureau publishing program, we guarantee a continuous flow of trans- lation in your specialty. lf, you have,a native?com- mand of English, a good knowledge of Russian, and experience and academic training it+ a scientific discipline, you may be qualified for our program. " Immediate openings are available in the following , fields: physics, chemistry, engineering, biology, ge- ology, and instrumentation. Call or write now for ? additional information:. TRANSLATIONS 'EDITOR t CONSULTANTS BUREAU 227 West 17 Street. New York, N. Y. 10011 ? (Area Code: 212) AL-5-0713 _ Declassified and Approved For Release 2013/09/24: CIA-RDP10-02196R000700010002-5 kr? ? I 4 ? , ? ? Declassified and Approved For Release 2013/09/24: CIA-RDP10-02196R000700010002-5 I: 1 - ? ' ) 1 i? - ,1 , , , _. ... . , t- Annoitncing - ? . , . ? , . ,... ?. _ ... ?--,,,-- ' An: important 'new 'book,.. ft9.th Plerium'Press, , , in die field of Geophysics :',.? f. -\? , ) ' ? A , ' O MAGNETISM -'-'seoOnd revised editioW 'Rock 4 -/ ; -- l? ' - -.). - _ /..., This book, the only available on the subject of rock magnetism, ? ,, ? Is ,, , _ ' has been carefully reviied'and considerably expanded in .light , , ?. , , ( ? of the fourfold Increas-e in research being\Oarried Out-in the field ?-?., ; ' 1,_ \ ' - since the firSt edition. ' ,, - ..,,,,, c?. ,. _ - . k ./ , , .. t -IA ? .., 1 '' ' 1 ' It ;beg i ns 'with:a nutl i n e of ferromagnetism and,.descriptions-of the, ' instruments Used in the 's,tudy of rock.megnetisrri. Accounts are given . Of the Magnetic properties of rocks and of roak-forrnipg Mineral's 7- , the latteran area in which Japanese' research,ers-have,been . 5 'outstanding: Thedifferent Weys in which rocks become Magnetized, . . . , , are then dealt with, i.e., TRM-(thermal remanent magnetization), \ .'- a. ;CRM (chemical remanent magnetizatIon,-7 a-Subject of great importance to 'paleOmagnetists), 13RM" (depositional remanent- magnet;ization), and other types of secondary magnetization ?) ? A COnsideretiOn of the ways in which rock' Magnetism has been--",- , --- -,N ,. , , - put to work i,p\geolOgy and, ge'ophysi'cs 4onclt.ides'th4 bpok. -, ., . ?-' .? , ' ReSearCher's'in rock magnetism as well .s'irl'relaied fields such as k N .palpornagnetism and archeomag'nefim, will this work an , .,. -?? , r - invaluable refer,ence:_lt is also pertinent to,.geophysiCists interested in '-'the interpretation of magnetic anomalies caused by rockbodies!' _ \ -,- '-- `\ 362 pages i', . .e..- ? 1965 , ? '.. t $9.50(--- -/ / , ? i 1 ' , - I 1 ' I / ' 1 1; Plenum Press, 2'7 .. W. 17th. Sireet,, New York, N: y:- 10611 ' ' 4. 1- ? ,- i \ ; 5y-T. Nagata ' A-, I 4 Declassified and Approved For Release 2013/09/24: CIA-RDP10-02196R00670601000215 , ,9 4 A I N.