SCIENTIFIC ABSTRACT SOKOL, G.A. - SOKOL, P.F.

• Document Type: CREST
• Collection: Scientific Abstracts
• Document Number (FOIA) /ESDN (CREST): CIA-RDP86-00513R001651920015-1
• Release Decision: RIF
• Original Classification: S
• Document Page Count: 100
• Document Creation Date: November 2, 2016
• Document Release Date: August 26, 2000
• Sequence Number: 15
• Publication Date: December 31, 1967
• Content Type: SCIENTIFIC ABSTRACT

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AUTHORS: Baranov, p.s., Slovokhotov, L.I., Sokol, G.A. and
Shtarkov, L.N. ------------
TITLE: A Differential Method for Determining the Efficiency
of a y-counter
PERIODICAL: Pribory i tekhnika eksperimenta, 1961, No. 3,
pp. 63 - 66
TEXT: The pros-ent authors describe a method which can be
used to determine the efficiency of a y-counter in the energy
range up to some hundreds of MeV. The method is based on the
recording of coincidences between the proton and the y-ray which.
appear during the photo-production-of neutral mesons on hydrogen
A block diagram of the apparatus is shown in Fig. 2.: The Y-ray
beam has a maximum energy of 265 MeV and was obtained from the
synchrotron of the Physics Institute of the AS USSR. It was
collimated by two lead collimators before reaching the liquid-
hydrogen target. The latter c2nsisted of a thin-walled
container (brass wall 15 mg/cm thick) having a volume of
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A Differential Method ....
3
100 cm Protons from the reaction:
Y + P P + -J~2
I-rP 2y
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(2)
passed through alumin~-.un windows (250 11) and were recorded
by a telescope consis-Ing -of three proportional counters
connected in coincide.tce (resolution equals 2 x 10-"' see) and
a single scintillatir-t counter connected in coincidence with a
y-ray crnter (resol,-..ng time of the fast coincidence circuit.
5 x 10 see). The iroton telescope records protons with
energies E p + AEp , where AE p is determined by an absorber
placed in front of '.ie telescope and the discriminator of the
third counter. The rotons are separated from the charged
mesons in the first , knd second counters of the telescope, using
the difference in tt-~ specific energy losses of thAse particles.
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The y-counter consists of two scintillators (3-5 g/litre
solution of para-terphenyl in phenyl-cyclohexane). The
scintillators are 15 cm in diameter and 3 cm thick and are
mounted on �.;Y-,35.(FEU-33) photomultipliers. In order to
increase the efficiency of the y-counter lead converters -
0.8 cm thick, were placed in front of tl?e counters. Thez-;f
scintillation counter in the proton telescope consisted of
a plastic scintillator (terphenyl in polystyrene), 0.5 cm
thick and 6 cm in diameter. It was mounted on a perspex
light pipe and an FEU-33 photomultiplier. Recording of the
coincidences between the scintillation channels was achieved
with the "fast" coincidence circuit described by
A.A. Rudenko (Ref. 1 - PTE, 1958, No. 6, 60). The resolution
and efficiency of this coincidence circuit was checked in
special experiments. The efficiency of recording of the
coincidences turned out to be 95% In these experiments there
was an appreciable proton background due to the target walls
and the Compton scattering of the y-rays
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Y + p = Y, + P,
(5)
The proton background was determined with an empty target and
was found to be 10%. The proton yield, due to the reaction
(5) was neglected since the corresponding reaction cross-
section was lower by two orders of magnitude than the cross-
section of the reaction (1). On the other hand, the py-
coincidence background can be excluded entirely by suitable
disposition of the proton telescope in the y-counter. Fig. 3
shows the efficiency of the y-counter q (in 00 as a function
of the y-ray energy in MeV. The points are experimental and
the curve is calculated from the formula
(bT - I,y 0
11 - exp(-2liT JI 17(bT) (6)
where IL is the y-ray absorption coefficient for lead
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(Ref. 2 - Heitler, V. - Quantum Theory of Radiation, 1956,
Izd-vo IL), T is the thickness of the lead converter,
(bT - 1, y0)1 is the incomplete gamma-function,
b = 2.6 cm- (for Pb), yo = ln(Em'/Em in), i'ax is the
Epine e e
maximum electron energy and e is the minimum electron
energy corresponding to the threshold of the fast coincidence
circuit (2 MeV). If the proton telescope records only protons
with energies E p + AEp , leaving at an angle t9 p �-A Op to
the direction of the primary Rhoton beam, then the kinematics
of the photo-production of Ir -meson (1) and the 119-meson
decay (2) can be used to determine the energy spread of the
y-rays recorded in coincidence with the protons.
Acknowledgements to P.A. Cherenkov for his interest and to
T.I. Kovalewa for taking part in the construction of the fast
coincidence circuit.
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There are 3 figures and 2 Soviet references.
ASSOCIATION: Fizicheskiy institut, AN SSSR (Physics
Institute of the AS USSR)
SUBMITTED: August 3, 1960
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S/056/61/041/006/004/054
B 1 08/B 138 -
AUTHORS: Baranov, P. S., Slovokhotov, L. Shtarkov.L.N.
TITLE: Elastic scattering of 247-Mev gamma quanta from hydrogen
PERIODICAL: Zhurnal eksperimentallnoy i teoreticheskoy fiziki, v. 41,
no. 6(12), 1961, 1713-1721
TEXT: Experimental data are very scarce on elastic gamma scattering from
hydrogen involving energies higher than the meson photoexcitation
threshold. Such information is indispensable in establishing a theory of
Compton effect in this energy region, and may provide information on
proton structure. The authors studied the angular distribution of gamma
quanta, with energies of (247 t 10) Mev, scattered from liquid hydrogen.
The coincidences of scattered gamma quanta and recoil protons yvere
recorded. By determining the energy of the recoil protons at a fixed
gamma energy, the desired process Ir + p - p I + (1) could be
distinguished from the background process r p p , + Ro (2)
el +
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Elastic scattering of 247-Mev.,. B100138
Results are given in the Table. The error in the cross section of
reaction (1) is about t 15 %, Only for departure angles of 56 and
740 (c,m,s.) of the gamma quanta does the error amount to some 25 %. The
resuits are -in qualitative agreement with those of other publications.
Discrepancies between the experimental results and theoretical calculations
on the basis of one-dimensional dispersion relations are mainly due to
deficiencies in the theory. The studies were made at the synchrotron of
the Lebedev Physics Institute (see Association entry). The authors thank
Professor P. A Cherenkoir. Professor V. I.. Goildanskiy, Doctor of Physics
and Mathemati-ca A. M. Baldin, and the synchrotron team for their
collaboration- N. N. Bogolyubov, D, V. Shirkov (DAN SSSR'_!L~' 529, 1957),
L. 1. Lapidus, Chou Kuang~-~hao (ZhETF,'~9_, 1056, 1960), and N. F. Nelipa,
L, V. FiVkov (Preprint FIAN, A-2, 1961) are mentioned. There are
9 figures, I table, and 17 references: 9 Soviet and 8 non-Soviet. The
three most recent references to English-language publications read as
followsi M~ Jakob, J. Mathews_ Phys. Rev., V7, 854, 1960; R. Blokil
et al- Phys, Rev, Lett., 5, 384, 1960; A., V, Toliestrup et al. Proc.
!960- Ann. Intern, Conf. an High Energy Physics at Rochester, p, 27:
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Elastic scattering of 247-Mev... B108YB138
ASSOCIATION: Fizicheskiy institut im. P. N. Lebedeva Akademii nauk SSSR
(Physics Institute'imeni P. N. Lebedev of the Academy of
Sciences USSR)
SUBMITTED: June 9, 1961
Legend to the
Table: i
degrees, (2)
laboratory system,
(3) center of mass
system, (4) ratio
4) of
10 the
products of
reaction N to
reaction 2
cm2/s
(5) teradian.
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> > omotneune
9,
9
1x0
0
to ATIFY
Z4 R4 Z 4 J 0 X b
A
(XIO, Pen.
"
1
2 "Blemepda

4

4 ) x (
A
)
( (C. a. M)
3

16 W 104 15,5 �1,65 148,0 247,7 5 140:h f 2 4j7�0,35
24 121 94 23,5 �1,70 132,2 247,8 5 ItO�9,0 3,33�0,28
36 94 140 35,0 �1,70 ~
108,8 247,2 5 - 74�8,0 3 09�0 33
44 78 - 42,5 �i,70 93,1 245,2 6 25,7�2,7 2:08�0:24
56 56 94 54,5 �2,0 70,3 237,0 �15 9,43�t,37 1,60�0,20
64 42 76 62.0 +-2,0 54,8 232,6 �15 8,07�1.07 1,34�0,18