"FUNDAMENTALS OF INFRARED TECHNOLOGY"

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• Release Decision: RIPPUB
• Original Classification: U
• Document Page Count: 164
• Document Creation Date: December 23, 2016
• Document Release Date: March 27, 2014
• Sequence Number: 1
• Publication Date: September 26, 1958
• Content Type: REPORT

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R
STAT
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TECHNICAL IINTELMENCE
TRANSLATION
1121111:1112=DINCIEEEIC:=111110Z,Miffimo
(Title Unclzasifion
7UNDAMMT..13 07 ITOD.ZeDe TIM:014a
(Ocaory I/UW=4=y T. 1)
by
I. A.
I. P. Mops:taw
Source: Military PablishLva losses
Ministry of Deco USSR
Moscow
195i
263 Pallai
cAIt TECHNICAL INTELLIGENCE CENTER
VIOSOulf-IPAVIC.-P=A A Kt= OA=
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STAT
I.A.Margolia and N.P.ttayantsev
FUNDM:E?iTALS OF INFEAFIEC TECHNOLOGY
Military Publisltiag House
Miaistry of Cefease USSR
Vasco,. 19SS
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AUTHOFIS' PHEFACE
Infrared rays are being increasingly used in various fields of science and tech-
.__
--'nolegy. The rising interest in this field of the
- latisns is therefore understandable.
upectrum of electromagnetic oscil-
During recent years sany works on the principles of physics and technology of
--the radiation and registration of infrared rays have appeared. The authors of the
- book have set themselves the task of svatamatizing and summarizing these scattered
data.
In this book, presented for the aztentioa of the reader,
are the principles of
- the physics and technology of radiation, propmgataon, and reception of infrared rays
- --including a number of data of handbook character.
This review oaken no claam to exhaustive coverage of the questions discussed,
_since it is one of the first attespts to systematize the materials in this field. It
iay be used as a handbook and a textbook.
- The introduction, Chapters I-VII, and Section 75-76 of Chapter VIII, Sec-
__tions 82-84 of Chapter IX, and Chapter XIII have Lees writtea by I.A.Margolin; Sec.
tion 77 of Chapter VIII, Sections 78-81 and 85 of Chapter IX, and Chapters X to XII
-V' --by the late N.P.Ammyantsev.
; 4
? --:
on the Fifth Five-Year Plan of developsent of the ISSIt for 1951-/955 point out the
INTBODUCII(Xii
The historic directives of the Nineteenth Cmnrreus of the Comnunist Party CSSF
-.necessity of widespread automation of the production process, aid of increasing,
2.= --vithin the Five-Year Plea, the production of isstil.-zents for control, automation.
:71--and iftlesechanits by about 2:7 times.
A number of such isstrmments use elements of infrared technology. Infrared
--:technoloty is a new branch of seders technical physics, covering a side ranee of
:: -.problems cosines:Led wick eke physics of radiation, prepagaPioe, and recording of in-
__
-:__frared rays, with the technology of develornent 'ad manufaetarc of iafrarei real-
-, - eters, with the technology of the Aevelopment of indicators (radiation receivers),
,4--special optieml systems and optical filters, and with the application of these ele-
- --ments to variaos scientific research fields, as well as to industrial and military
.. - purposes.
__our
'I
The developsent of infrared technology is isseparably naked with the names of
greatest lussias scientists.
la 1878, the outstaadiag Bossism electrode technologist P.N.Yablochkos isventea
4 t
--a radiator with an iscasdeseest body ia the fors of a rod made of a mixture of ha -
__olis and sagnesia. This radiator is a very good source of infrared rays and is
_-t- herefore widely used is various scientific studies.
Is 1888. the outstanding Silesian physicist ,..CuStnletev was the fisst to give.
--a scientific explanation of the phesamesoe of the external photoelectric effect.
- establish its basic laws, and construct the first Prototype of the photoelectric
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4?4111. ??????
f.'
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_ - . ?pr wierftriellerelee-tat "r;?.?"
:rce-11.
In 1295, the great Russian physicist P.N.Lebedev designed de firet prot.ot71...t
_Jof the vacuum thermoelectric cell, one of the basic forms of indicators of infrared
_Jrays.
In the postwar years, Soviet industry achieved great success in the introductioa
and mass production of various fovea of modern isarared instruments to meet tht-.. re-
-
quireeents of the nationcl economy. These instrements, designed under the guidance
and participation of great Soviet scientists and specialists such as A.A.Levedev.
G.S.Landsberg, G.G.Slyusarev, A.I.Tudorsv;kiy, I.A.Shoshin, and others, are superior
????? I
1 in a number of basic parameters to analogous foreign prototypes, which is evidence
:1_ of the high scientific and technical level of the mechanical optics industry.
1"
The design of the individual elements of infrared technology and the solution
2.__of the coaplex theoretical questions were propagated by the Soviet scientists
A.A.Glagoleva, Arkad'yeva, M.L.Veyngerov, B.P.KoLyrev, MI.A.Levitskya,
? --N.C.Smirnov, N.N.Tereein, P.V.Tisofeyev, N.S.Khlebnikov,- V.V.Shuleykin, and many
--others.
- There is no doubt that in future years, infrared technology will make new sad
- great advances in its development.
24-1
36__
30-
4
44
5E, __i
0
U.
CHARIER I
?
aa a
BASIC CONCEPTS ANC DEFINITIONS RELATING TO RADIANT ENERGY
It ?
__Section I. Bedizat Energy
The energy of visible and iavisible rays is known as rediact energy. Padiatiom
- the visible region of the spectrm (visible rays) is called light.
r
rave and quamtnm properties- Certain optical phenomena are well explained by the
Is modern physics, light is considered a flux of materiel particles possessiag
2E_
Relation bets-ecu taits of Measperesent of faergy
(lit
...--
I I
/
j,...mie
kilzjcd.? e
cal
1 kcal
1 erg
1 jowl*
1 kilojoale
1 cal
1 kcal
I
1 1
1 107
leo
4.18 x 107
4.18 x 1016
.
10-7
1
16
4.18
4$x 10
.
10-11
10-3
1
4.13 x 10-3
4.18
2.39 x 104
0.239
1
10
2.39 )4 1041
2.39 X 10'4
0.239
I 1r3
1
--wave mechanics of light, others by the quantum theory- The wave properties are due
--to the fact that light consists of electromagnetic waves. The quantum properties
- are Characterized by variations is the energy of light in definite portions knoem
--as light qsaata.
5: /
- If radiant energy is absorbed by bodies on the path of its p...mpagatioa, it is
_ . _ _ _ _ _
__transformed iato other forms of energy, thermal. electric, or cheaical1 with the law
This is also true of the radiant energy of the isvisible part of the spectrum.
-
STAT
1
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a:
?
lerVitligreie=ftgle=1, '42/' "??.... ? : ? ?
- conservation of energy ben g obeyed.
2-1
Radiant energy is restored in ergs (erg); joules (j) and caltifie4.(col).---
_-___
'Table 1 gives the relati?ns between these units.
12
I
_- Section 2. Quantitiea anracterizing the OscilliAllty Process
Electromagnetic oscillations arc characterized by the saws
ionhasental quantity
as mechanical harnonic oscillations.
If a point executes harmonic oscillatory motions shout a poiht of equilitriomA
- the doviation y -row this position f>r any instant of time t in found Ironthe forms
--?
20-4
where
--:] y
36_2
i
y I' A cos (2K - c)
(I)
A = amplitude of oscillations (maximum deviatiou from the potion of equil-
ibrium); ?
T ? period of oscillation (time of one full oscillation:
initial phase (quantity defining the deviation from the point of equil-
ibrium at the initial instant L 0 0).
By laving off the time on
the abscissa and th? value of the deviation y on Chi
ordinate, we obtain a graph of the harmonic os-
cillatory motion (fig.1).
tgalled the ph ase
The quantity 2 x -
T
of the oscillations at the inktfAt of tire t.
After ever!, period, i.e., at t equal to TA 21, 3/1
4;_-
_
Fig.1 - Graph of Hermetic
Oscillatory Motion
Tha number of full cycles o
of oscillations v.
has-heea
etc, the deviations y are the imme in magnitude
and sign, for example at the inmtents or time ti
end t2. This corresponds to th# same phase of
oscillation.
oscillations in unit time is called the frequeecy
This quantity is reciprocal to the oscillatiom period. Iho
sJopted as -the-unit Of oscillation frequency. This is the Ire.
I
I
-
?45. dellor?V
0? --
I
-quency at whirh one full oscillation takes place ia one sealed.
- _The prkpaeatioo
-4
1 4 --.
of oscillatory (wave) notion in any medium is characterised by:
the wavelength A, equal to thk distance between the two nearest points cor-
resple4ing to The same seplitudii-and
the velocity of propagation of thc wale motion v, eccal to the distapee at
which the wave is propagated in unit time:
v ? -
T
(2)
Is a eediva with a refractive index of n, the velocuty of propagation of the
1E_
wave notion will be
12
where c is
4
dex of n
? -
a
(3)
the velocity of propagation of light in a median with the refractive ja-
il equal to 977. 1 II ksistc
Table 2
Relations between Units of Savelcaga
1 Unit
-...-
If
CM
a
No
?
1
X
s Zti
141 106 610 01.
102
103
10
1.13
1013
1013
1
10
104
le
10
1011
134
1
103
10
101
ltt14
10- I
10-3
1
103
134
0
10-1
Kr4
10---
1
lo
le
urs
lir?
lir+
io-i
1
HO
Ira
lo-le
le
10-4
1O-3
1
The aovalgogth A, the velocity --1 light c, the period T and the frequency w
, - are uorrelatej by the radiatiem
54
= = 4
(I)
F:___ fieCtrOOSIAttiC MAIMS hay, a very.wide rang. of wavelengths; thereiormt.y.e,__
???
--3-
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? MIN?40.V../.. .1????10
?
it?
? 4.
,?1 -tar "a?IrdoVialallItTP55*VIMIlita...-sca. "'err ? ?
0 1
- gether eith the units of lorgth used for measuring radio waves (m, cm, mm), snits .
-Me the micron (O. millimicron (n11). Angstrom (A),_and roentgen (X) are also used
'-lin the short-wave region of the spectrun. Table 2 gives the relations between these
6 4:units.
=1_1
I 2 ?
--!
22_
_
34_
Section 3. The Spectri-,i of Electromagnetic laves
The totality of all electromagnetic waves forms a spectrum of electromagnetic
waves with wavelengths froe
44
"
43_
43_
5v :
be
52-4
? lo-11 to
3x
101? cm. This spectrum can arbitrarily
Table 3
Scale of Spectrum of Electromagnetic laves
4..-c.-rus region
lavelenstb
li: conventional emits
is cm
Low-frequency az:illations
Long
Medium
Ftadio
eaves %art
Ultrashort
Microwaves
1=g-weve
Infrared Medium-wave
nye
Siort-wave
Red
Orme,
Yellow
Visible Green
rays
Blue
Deep blue
Violet
Ultraviolet rays
X-rays
Gomm rays
Longer than 20,000 ?
20,6004=0 a
2000-200 s
200-IC la
10-0.5 a
shorter them 0.5 ?
420-10C it
100-15 IL
15-0.76 ii
7600-6200 I
6200-59U0 A
5900-5600 X
5600-5000 I
5000.400 4
4800-4530 A
4500-4000 I
4000-50 I
50-1).04 I
40 X sod shorter
Longer th%aie 2 x 1)4
2x 10 ? 2 x 103
2 x 103- 2 x 104
2 x 104 - 1 x 103
1 w 103 - 0.5 x 102
shorter than 0.5 x 102
4.2 x 104 to 1 x IC"2
1 x 10-2 to 1.5-4 104
1.5x 10-3 to 0.76 K 10"4
0.76 x 10" to 0.62 x 10"
0.62x 10-4 to 0.59x 10-4
0.59 x 10-4 to C.56 x 10-4
0.56x Irr4 to 0.5 x ""
o.s x io-4 to 0.48 x 10'4
0.48 )t 10" to 0.45 x 10"
0.45 x 10" to 0.4 x 10.4
0.4 x 10'4 to 5 x icr7
$ x 104 to 4 x 1044
4 x 10-15 sal shorter
divided into separate rcgiona tibia, in part, overlap.
Figure 2 gives the range of the spectrum of electromagnetic
5i_i,
iEhac aqale. Table 1 also gives the ulvision of the
5:".?
- ? ?
waves on a loser-
spectrum into separate re-
1
a
?
?glens.
The gamma rays are the eatresa,..shortest rays of_te_spectrun and are radiated.
radioactive elements.
X-rays are very start electrcelatnetic 'awes escitta by solid-bodstruck' by--
144.
--hugh-speed electrons. X-rays have high penetratiag power and act strongly on the
organism-
The region of ultraviolet rays is bounded by the regions of X-rays zsZ visilla
rays. The electric arc, as well as quartz and mercury lamps, are good techaical
-sources of ultraviolet rays.
-
Ultraviolet rays can le detested by photographic setlods, fluoresceace
17: _
and phczOwirescence caused by these .rays, sod by ctana of ;:hotocells and tberao-
electric oells.
The visible rays occupy the narroweot sepient in the electransetie spectrua:
-'-0.4-0.76 4. It has been demonstrated by Soviet scientists, particularly by
that the boundary of the region of the spectrua is deterained
Th the power of the radiation mw.wice and the degree of adaptation of the eve. Than,
.
in the infrared region of the spectrma, tile threahold of sensitivity of tke eve goem
--as far as 0.86-0.90 i wbee the poser of the xadiatiem source is increased by kamdrede
:2
? of tuistiTrei tiniarir The properties and ,egions of application of the visible
__- rays are kmomn from courses in physics.
Infrared rays, invisible to the eye, occupy the reocioe of Vie spectrum fres
2:--atoot 0.76 to 420-420 a, lying betimes' the red rays of the visible part of tile spec-
4t--trum and the ultraahort radios waves They possess the sand properties as the visible
::_and "(hr....violet rays, i.e., their propagation LS rectiliaear, and they are refracted
4.__.n.- ad polarized. lefrared rays are radiated by the outer electrons of atoes mad note-
,
.t--cul,.a? as a rasult of rotary and oscillatory motions ?fiche moIecales.
These rays are sometizas called thermal rays siace their radiatioa is de-
termined by the temperature of the rediatiag body.
-7Thu nethods of excitation and detection of infrared rsys vary according to the
-,
--mpectral areas.
. 71e region of infrared rays may be arbitrarily divided late three regions of
- - -
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STAT
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?
? ra??????????? ?????.?0
0 _
- the spectrum: short-wave (0.76-15g).
nedius-
.uye (15-100g) and long-wave (110-420g). flhe.
inhort infrared rays (0.76-150 are the most
- fully inweatiyated and utilized in technol-
--,
ogy. . They may be divided into separate
zones according to the type of receivers
- used.
Infrared rays of a wavelength from
0.76 to 9.3-1.511 ire detected by photocells
ia_oith external photoeffect, by specially
2:-.)_- treatted (infrared-sensitized) photographic
platco, and by the methods of extinction
,.?of phosphorescent screens. For the record-
r
?ing of infrared radiation in this zone, all
?forma of thermoelectric rz.ceivers and photo-
-cells with internal photoeffect and with .
-?'-
-photoeffect in the blocking layer are also
32
Sources of infrared rays in this por-
,
?.tion of the :spectrum are electric incan-
3
_descent lamps, various gas-discharge lamps,
.1f
and all heated bodies with tcw.perature
?above 28068.
To detect waves of wavelength from
.? ?
?1.3 to 711, photcc-_-113 with internal photo-4
'---4effect are used, as well as all therm-
- electric indicators. Sonrcus for such
waves are electric incandescent lamps,
3 ? .-high-prematare- and extreme-preszakre arsairy.
lamps, special rod and cap rodistors. $44
SA:
4.4 `,10.. NeVYW.1111.11W,MMIPPW5WMAGL.11.1.
sq
a
I
i
1
-.:all heatwel-bodies with temperatures above 701(. .
i
t
... The bouodary wavelength o.f 15o for 'No! 7 to 150 portio:v of.. the spectrum is de-. 1
.. ,
--1 s
Ii
_ tersined Ey the absorotio* of infrared rays in the atmosphere: water 'vapor, almays
1
._preeent in the ateosphere, alnos: completely absorbs isfrared-rav-a?Cflavel;:eitl-ti-- I
? longer than 14-150.
_
Sources of infrared rays of this part of the 'spectres are all heated L4-dies of
- te&-peratures :stove 459: as sell as rod and cap radiators.
Infrared rays cf the long-wave portion of the zpectriva have not yet Leen
- studied much. Their sources are all Ladies at tesperateres above absolute zero; but
IP ?
3. ).? . : ? the energy radiated by thee is so =all that it can hardly be detected by seasitive
4 44 4
X 0 W ta
le
u ? C; o .7... ? -- the,rroelectric receivers. lorks by the noted Soviet pUysicizt A.A.Glagaleva-
??? m .. ....44
0.1 ? ..) _a I. ?
^ z a
... : . ? Arkaci'yeva are devoted to this region of the isfrared spectrum. He has built a
x ..... 6...I
4 V ??? P. ?
at
I .... w 0 : ? _ special radiator (mass 'ra4iator' emittiag infrared revs of waseleagths up to about
0
AJI ch, 0..
0 0 )a? f???? O.1 330.
e u 4 .
....ii , ? ; LI ii ; ?
, la 3. ,
'Midi* waves an waves which have wavelengths from millimeters to a few kilo-
s.
o .o iso -oe s:
--
li .. loft s. 34 ? *eters, and are widely used for radio coezunicaticte, radio broadcasting, radio lo-
o ..... . e --
s? m at I. ...a
ri .."4? 3" " -
c -- catioa, television, etc.
0
G 0
0. In .... -88
. _
Low-frequency oscillations have the longest waveless-a. Their sources are in?
^ a-.
t..s .... ? ... 14
O I t ? ?
? TS ? vi. ? ? - ?clustrial alternating-=rreat generators.
a ..;
?.4?
la re
s s. 4 4 ? 0
_ ?
o a
it ..1 0 -.4 lis
s. a ---
Ca
? ..c 0
0
A Be 4r..._.
It ?
?.;
:a. iii a .. .... ta. .... ...c
_
1
5:72
5
???1..1.1*.i1GAS
_
STAT
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CHAPTER II
?
ENERGETIC AND LIGHT-TECHNOLOGICAL QUANTITIES
--Section 4. Energetic Quantities
* *.3.4 11.,` vriK*111,411111111:12P
Radiant energy-ami all quantities related to it are measured in energetic or
_
- ?light-technical units according to the spectral composition of the radiant energy
,--nnd to the features of the receiver used for the neasurement. Energetic quantities
-
are used when the receiver reacts in the sane way to radiant energy over a wide
--range of the !spectrum of infrared rays. Receivers of this type are called nonse-
_.lective. Such receavera are, for example, thermoelectric cells which transform ra-
through
J.1....-
I ?7
--angle 4.., rough which it is propagated: 1
- client energy into thermal energy. _-
".t.: d#
.,
If selective receivers whose reaction depends on the spectral compositioa of TOM ' dm
a..-m-tsmvarc.v.-rw? - - -
'6IVS ? ? a.
Raiiant flux is messured in units of power.
? are given is Table 4.
. ?
6 ? ?
Table 4
(5) ;
The relatL? tactritg.re_Lhese units
Relations hetseen Cee.ais Units of Power
Unit
---
------
I erg/sec
cal/see wet kw
1 erg/sec
I 1
2.39 x 104
Br' to-"
1 cal/sec
4.18 x 101
1
4. 18 4.1S x 10-2
1 watt
101
0:=9
1
io-3
kr
101e
la,
101
1
.
---...
--Energetic Power of Light
4. .
- The energetic poser ^f light Iva represents the radiant flux
per unit solid
? ??????
the radiant energy are used for the measurement (such as photocell or photographic
--plates), then the selection of the unit of messurement depends on the band of the
1:-? --spectrum in which the receiver operates. In the infrared region of the spectrum en-
quantitiea are usually employed. For measuring radiatt energy in the via-
2__- ible region of the spectrum, optical-engineering units are used permitting aa evala-
4_ atton of the perception of light by the eye which reacts to a radiant flux only in
.6_the visible region of the spectrum.
8-- -
hadtant Flux
Ihe quantity of energy radiated
- hf the radiant flux is
--eagle u, thee
a "L.__
44--
stew..
(6)
uniformly distributed withia the licit: of the solid
(7)
The energetic power of light is measnred in w/ater, erg/sec-stes and cal/sec-
Note. If the area S, equal to the square of the radius of the sphere r is cat
--out of a sphere and the boundariet of this area are connected with the center of the
(absorbed or transferred) in wait time is called
- ,the radiant flux 116
-1---114-during-the-tise-interval- t, the radiant energy I. in radiated,...0to.k..tht.
'6--
^
-2snbere, thews the solid eagle will be equal to unity, since at S ? r2
51-7
54 1
E6
111 ? Al 1
W2
9_
;v,
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'
.?????????????
4
a
s .6--vnerogirsersisscsrm,m~+y4.!? '
-
- - ? - ? - ?
Therefore the solid angle, cutting out on the surface of a sphere an area enual!
?
di
'Gs
I ;
? ..to the *guar* of the radius of this sphere, is taken as the unit of solid angle and
E
a
?-?-??
COgi
. r2
7'is called a sterotHan (ster).
^
The solid angle u is related to the plane angle by the relattow----
= 21t(1:- coo d) (9)
The quantity 44 is dimensionless.
_Energetic Illtunination
The radiant flux incident on unit irradiated aurface is called Che energetic
-illumination, or surface density of incident flux, and is expressed by the formula
22,
:
3 -'
I
4v__
E a ?
*a dS
where dS . element Cl illuminated surface;
(10)
di . flux incident on this element of surface.
If Che surface is illuminated LT t 4iat source over the definite solid
s
rf
-1
angle du, eq.(10) takes the form
Fig.3 - Diagram for Determining
Energetic Illumination
E I ---
is ea ds
Let us imagine that Che roint source of
light C (Fig.3) with the energetic light intea-
sity Tea, illuminates the surface element dS in the solid angle dA. Thee Che solids
--angle inishich the elemenc of surface is illuminated is equal to
---Where 4 . angle
r ? distance from the source to the center of Che area dS.
d3
--- cos 4
r*
formed by ray incident on the surface and the normol N to it;
_ _ .
Substituting Che value of du from eq.(12) in eq.(11),--IWEet
(12)
Equation (13)
s
wcpresses the law of-iaserse aqua-es, accerdifig-ii-WhICh-thell:
slumination of a surface is directly proportional to the light intensity 4nd inversely
'proportional to the square of the distance between the radiator and the irradiated
- surface.
I watt/ Energetic illumination is censured is ca2, erg/sec-cm2
--Energetic lcminositv (Illucination)
and cal/sec-cm2.
The radiant flux emitted by unit of radiating surface is called the energetic
ot the surface deosity of the radiant flux enitted. The energetic.lumi-
-...--nosity is defined by the formula
A. ?
da
Pea dS
--- where di is the radiant flux radiated by unit surface dS.
BriAtness and illumination ar.: *ensured in the same units and differ only is
-_,- that the brightness charncterizes th.1 -adiation from this surface, while the illumi-
zastion characterizes the incidence of the light flux on a surface.
Energetic Brightness
The radiant energy emitted by unit murface is a speeifiej direction is called
.1--
- energetic brightness. The energetic bri Otaess Bea is equal to Che quotient of es-
-1 t
ergetic luminous intensity of a surface measured in a gives direction by be area
of ti, emitting surface projected onto a plane perpendicular to the direction corn-
-
__
51-3,
54-1
-:where dls a energetic luminous intensity in the given directsoe;
. 21 _
a
" dS coo
(15)
STAT
?
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? ?MmIlls?
....????=,..10. ????????
0 --:-
a . angle between mirmal to the surface and the given direction.
2--;
_ limn ...luminous flux is emitted uniformly in all directions, the energetic
_
'
-4brightness is defined by the foioula
?
...IS: Tr 'Or .4,441,4.11ri?WSII.r.-..-V"' .? A tt! ? ? - ? ----7-4,????- ?????????2:7--.W.
.. ?
die,
13411 dS
Energetic brightness is measured in wattistez-cm2.
2 ?
- The Cosine Law. Relations between Energetic Qustitiez
-?
1 0 --7--
-all tue incident light flax regardless of :the direction of its.iacidence sad dia.-
--ideally scattering surface. Ad ideally scattering surface in ? surface reflectiag
I '
21tributing the reflected flux by the cosine law of radistion. A shite matte surface '
___ : .
is an alnost ideal scattering surface.-- ;-- - ?
?
?
(16)
A 'light flux incident on a surface is characterized by the illumination produced
by it on that sui face.
An ideally scattering surface coe?letely reflects the incident flux without ab-
-sorbing any of it; i. may therefore lo considered that it emits the same radiant
The variation in the energetic luminous intensity of light, depending on the - flux. Consequently, the energetic luminosity of this surface
1i...direction, obeys the cosine law in most cases: the luminous intensity of a radiating
:0_ surface of uniform brightness is proportional to the cosine of the angle of radia-
...tion. In its mathematical fors, this law may be obtaf,ned from eq.(15)
Ette
::_i.e., the energetic luminosity of an ideally scattering surface is equal to its ea-
.. - ergetic ilIuminatioa.
13
2:-_ Is ....... w --
?
--.OR Since the radiant flux is distributed by the cosine law, the energetic !right-
-
..,..._ 5 cos a '.......:
.. ?nets is a constant quantity and, according to eq.(19), is equal to (connideriag that,
:1--uhence the luminous intensity of the radiating surface is
?i--,
i
cos a (17) i
- --
32_,
.... _J ]
Bis 0 *2
____ X (91)
The cosine law gives simple relations ketween certain quantities.
- ---.
From eq.(17). if the energetic brightness is known, we can determine the en-
1: --i.e., the energetic brightness of an ideally scatterine surface is equal to its ea -'?
ergetic luminous intensity of. the surface and, consequently, alzo the total radiant
--flux emitted by it:
42
mileaS (18)
-"
4; 1
Substituting the value of 4 in eq.(14), we obtain the expression for the lumi-
nosity
ReS ItHelk
52 -:
Thus, the lumiuoaity of a murfece obeying the cosine law of radiatioa equals
54- its-energetic bzightness mults-plimi-by -
_.Let us find the relation between the illumination and the brightness of.sa
(19)
^
--for an ideally scattering surface, e, R a E )
eA
3.----ergetic illumination divided by a.
- Section 5. Certain Properties of the Hnsaa Eye
The properties of the eye play a substantial role in visual measurements of
- radiant energy. 181en a radiant flux ttrikes the retina of the eye, a photochemical
_- process takes place. It consists of the stimulation under the action of light of
4Z_?
certain photosensitive temninal nerve cells, the so-called rods and cones. This
--atimulatios is them transmitted to the brain.
I
The cones constitute the apparatus for daytime vision, functioning at high il?:
1:4-.._limaiskazioes,_nud the rods., the apparatua lar_noctureal_and twili&bt yisioni_faae-
!f_tlimiag_st_low illuminations, lhe.esnes enable us to discrimiaate color, _since
-
iL
?
STAT
? ti
???? ? a...a..
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??? 4?1????????? 4.1110??
?
?
- .1?14.- I .1111Wilrer.....1131 **TIV."" -.
:
...'they perceive the frequencies of tho lint spectrum differently.
The curves for the cones (C) and the rods (h) give the spectral senlitivity of
. _ _ _
- '
-;the eye, constructed according to the data of ProfeAsor N.F.fedorov (Fig.4), show
:that the maximum of rod sensitivity is shifted toward shorter wavelength (k 'I 0.507g)
-.J
t. r
. rt
+
ir'N
A,/ \c
_ II t
.'E r ?
r
44 I I%
42/ / %
I- ? Li
?
?
?
0
44 443 Ovi 0.55 0.5 045 0.7
a)
Fig.4 - Spectral Sensitivity of
the Eye
2 ;
- Hods; C - Cones
f,t_:- a) Wavelength, g; b) Spectral
- senritivity in arbitrary units
)
n A
'? teri zed
by the minimms angle of
with respect to the maximum of conc sensitivity
(X ? 0.5550.
The time required for the sensation of
light to be produced is from 0.1 to 0.25 sec, ac-
cording to the intensity of illumination (bright-
ness) and the wavelength of the light.
The minisum radiant flux fa,, capable of pro-
ducing a sensation of light in the eye is called.
the light threshold of the eye. The light
threshold of the eye is shout 1 x 10'" -
.5'12 erg/sec.
The renolving power of the eye is charac-
reaolutioa at which the eye is able to distinguish
,, ?
----two points or lines of an observed object. The magnitude of the resolving power is
2.4_ inversely proportional to the angle of resolution. Lbder the conditions ol normal
3,__illqmination and good contrast, this angle is equal to one minute. As the Maui-
3- - nation decreases, the resolving power decreases since the angle of resolution in-
4.- cresses, reaching 10-17' for observation in twi2ight or dusk.
_t
The eye is able to distinguish objects becanzt of the contrast between the
? -"brightness (or color) of an object and the background against which the object is
--observed.
--defined by the formula
.,H
54_1
-4
5:-.Where Be brightmeen of the object; ------
The contrast between the brightness cf an object and that of the bachground
B. - Bi
X a
Bk
(22)
is.
0
2u for tungsten, at X > 14u for silver, etc. With aid,
ficittlt accuracy, this can Le used for determining exT at waveleigthl lo?nger?than 4
I P. For wavelengths in the ultraviolet and visible regions of the spectrum, this
._
formula is unsuitable, since the results of calculation differ from the measured
1: -values. This can apparently be explained ty phenomena of resonance (absorption
bands) in the ultraviolet and visible regions of the spectrum.
- To determine the energetic luminosity of radiation of non-black bodies, the
1:7:following empirical fozmula has been proposed:
2 0......- .
BT
'22
'here al " a certain constant;
a = a quantity depending on the kind of metal used and on its temperature.
The values of a' for some metals have been experimentally de.tertsinted. Thus,
- for eIgimple, for platinum, a' = 3.56 x Nils, for tungsten, 1.51 x 10-1s, for
_nickel, 1.04 X 10'14
, ^
(91)
32_
For tungsten, eq.(91) has the form
RT 1.51 NE. 10'IST4-9 (92)
Equation (92) gives correct results in the temperature range of 2000-3000?K,
precisely at the temperatures corresponding to the working conditions of the
4:7 filaments of incandescent lamps. To determine temperature at which the intensity
,of radiation of platinum and that of a black body are cot perable, the approximate
formula
t5-
4 ?.1
51-,may be used, where
Si
561
co-1
^
Irpl?t
2892
aa ---- ?1.1
(93) ,
STAT
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?
??????.????? ??????
?
u-Nr-strieruse - -
--t The total radiation of metals may be deterpined by the formula
- -
.ExT - T4(.1 - eaT)
t -
--where 0 . a constant taken from eq.(60);
c--
(
-
'2 0
.1"
24--
where j electric conductivity of the
1
metal in ?
onm-cm
(94)
1
4 a constant depending on the kind of metal.
The values of the constant a for a few metals are given in Table 11.
The absorption factor of pure metals
in the region of short and medium infrared
Table 11
Value of a for Several Metals
Metal
a ? 104
n-
..emaust
I
1.08
Molybdenum
1.118
Cold
1.20
Platinum
1.25
Tantalum
1.31
Mingstem
1.47
Nickel
1.65
rays may be determined by the simplified
formula
0.365
"T 1
(95)
To A.teenine the maximum r??diation
-.for maximum radiatio.
-4--
Mit
-j For total radiation
I 10
-4
?
? - ?????sr????n-x-croccor? ?
1
s c . 2 2
? 1.334 x 10 p.74
f Exdx CI ? 4.936 x 10-107$6:-1757 (100)
?
; a Fouutiens (96)-(100) are true for wavelergths ?vet 411. Table 12, below, gives
!?._:Che emissivity factors of certain bodies.!
??? ???
-1
14 ;
3Q t
3S--!
4.
?
of metals, the following formula is recomisi.nded:
? O. 3651[PTI.
Enka I.
(96)
(9T)
32 _
34 !
36_
3c
V: ?
42_2
44
45 '
C:
(A...T)S.5 ( _ 1 )
To determine the total radiation
CI ? 8.156 x 10'1167T4TS
ExTdx 19
?
Putting p ahach holds for most metals, we obtain:
for selective radiation in the region from A to A + dA
CI -1
Ex . CI ? 0.022Ti(7.7X." (;57)
52.11
Values
?
Table 12
1
1
of the Emirsivity Factors of Certain Bodies (Bib1.3)
Bodies
Kind of Surface
Temperature.
IC
Radiation Factor
kcal/m2 hr deg4
'watt/0112 deg'
Lampblack
tram
Ira
Irma
Cast iros
Brass
Ie.
tater
Brick (red)
Silicate
brick
Same
Smooth
Cazefully poliabed
Bright
EU11, oxidized
Rough. strongly
oxidized
11211
-
IlDwet
Bamit
%ugh
Pew*
Polished
Dull rolled
Boo*
0-50:
40-24
30-10i1
20-360
40-250
50-350
0
ea
22 .
MOO.
LW ,
,
1000 .
50 ?
50
sn
4.3
1.31
1.60
4.32
4.39
1.05
3.06
3.20
4.6
4.0
4.2
3.5-3.7
0.53
3.10
3.68
5.0 x 10'4
1.53 x 10-4
1.85 x 10'4
5.02x 10'4
5.1 x 10'4
1.22 x 10-4
3.56x 10-4
3.72x 10-4
5.35 x 10-4
4.65 x 10-4
4.88 x 104
4.07_4.3X 10-4
0.62x 10-4
3.60 X 10.4
4.28 X 10- 4
Pefractory
brick
CoPPer
Copper
Copper
-4
56 cancl u de
this. Cheptcr by stating the concepts of calor.tespersturcaad. .
-41--
STAT' /
Ijo I
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1
a
? "'
_ se; ?a? ?Irme???ariarvereamMoirisaima.v..A ; '
??? I iwro.wArvo ???????44?.......????? ??? ? 41.?,?? w?la. ?????-??? ?
0
.ebrightness temperature, which we will often meet in the lei;,e1.
The color temperature I', is the temperature of a black body with the samA ratio;
of brightness between two given spectral regions as the given body at the tempera-
ture T. For all 'tetras the color temperature Tc is higher than the true temperature
P
--;of the body T.
r The brightness temperature 1 is the temperature of a black body of the same
;. - visual monochromatic brightness for a given wavelength as the given radiator at
--temperature T.
The brightness temperature is always leas than the true tamperature of the body.
20-4 1
--,
2
?
(-
39
-
.34_1
3a-J
.
40_4
42_ - !
/44?;
46 ;
48_.!
5n - '
1
ts ?
z..
CHAPTER IV
11_
1 t
--Section 16. Classification of Sources of Infrared Bays
SOURCES OF INFRARED HAYS
- The sources of radiation used today in verious fields of infrared technology
2
--Lay be divided into three groups, according to the physical nature of the radiatioa.
The first group comprises sources of incandescent radiation in which the infra-
24--
--red radiation takes place as a result of the combustion of a fuel or the heating of
__a body to a definite temperature.
The second group consists of electroluminescent sources of radiation operating,
(
? - on the principle of electroluminescence, or luminescence due to the passage of an
3 --electric current throngh rarefied gas.
The third group comprises sources of radiation of combined type, making simu1-1
.1--tanenus use of incandescent radiation and luminescence.
The "mass radiator' of A.A.Glegoleva-Arkad'yeva occupies a special position. Im
- physical nature this radiator is a source of electromagnetic radiatioa in the
!:..transitional region between radio wave and infrared rays and cohnot.be classified
tt___in any of the three above groups.
47_ Table 13 enumerates a few sources of infrared rays which are used is technology
.;,_,and scientific research, and axe considered in the present Chapter.
544
(
54
55
--Sectior.
!
17. Requirements for a Source of Infrared Bays.
The basil: requirement for ? source of infrared rays is high efficiency is the
-1
; A
?-? ?.
;
infrared region of the spectres. An effective source of isfrared rays Is Asses' os
?
?
STAT
?
ge
..?
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???
C.
(
?
0
-?--
the basis of the general laws of thermal radiation (cf.Chapter III), taking into Ale-.
I
.......count the spectral characteristics of the receptor .to be used for the .infrared rays,.
. ;
........??????
?
????? ...???????????????- ???? --, ? ? -? ????????? ? ...?????-??
. -
.
_
I
?r
Table 13
t- ? ?
A Few Sources of Infrared Rays
-
Type of S ource
.1--
4
t
Nature of Radiation I
Radiator
-
twscp I
Sources of Temperature
i
Radiation
Electric incandescent limpsFilament
with pure-petal filament^
'Mensal r..41atiom
-
of tongstem or other
refractory metal. heated to
incandesceace by an electric
curreat
Electric incandescent !maps
Filament of carbide or ether
filaments
Some
concond, heated to imeam-
with of metal
ccolPounvii.
descence by an electric current
Lamps with special incest-
Thexwal selective
Plate of kaolin in plug form.
by
desceettody
?
r-Aistion
t
hetted to :.------1--ceetce mm
electric currant
Incnadescent-mantle lamp
Santa
Silk mantle impregnated with
thorium oxide. heated to in-
candescence by the flane of a
gas or a liquid feel
Group II
.
Electroluaineacence
.
Sources of Radiation
?
basiaeseesee
Positive column glowing umder
Helium leaps
silent discharge La am inert
gas
Cesium lamps
Some
Positive column glades ender
arc discharge in cesium vapor
Mercurparc lamps
Setae
Positive cola glovdstgunder
arc discharge LIS SeXCAZ 1 TS;;07:
Group III
. .
Cnebined Sources of
&dieting'.

,
fTh
4
-;
Type of &wee ?ature of Radiation Radiator
Simple electric are 1
i.igh-istetunty electric are
Arc lamp with tusgasen elec-
trodes (point 1=p)
Extreme-pressure mercury-
tungstea leap
---------
Thermal radiation
vine luttineseence
.- ,
Same
Electrodes bested-to iscan-
desceoce !-.7 electric current.
incandescent gases. end lusi-
peRcett plaids.* callus of
an arc discharge
Same
Same
Tungsten spiral heated to is-
candescence by electric cur-
rent and Patine-scent posi?ive
column (4 arc dLscharge is
mercury vapor
Same
Same
_Ia addition to high efficiency, sources of infrared rays :Lust also
__of other requirements, naaely:
thev must be suitshle for use with optical synttemut;
they most not require special handling or observation;
they :::: have a sufficiently long life and stability is operation;
they have minimum possible weight and over-all size;
they Lust allow DC and AC poser supply under emergency operation sad must
!i-- permit convenient adjustment of that operation.
;
satisfy a
n=ber
Table 14 gives the energetic characteristics of a few sources of infrared ra-
__diation, for illustrative purposes.
Of the artificial sources of radiation is the Table, only the incandescent
electric arc, mercury and helium Imps are used in technology. The iscaa-
.
I _ descent mantle and the plug lamp, although they are sources of infrared rays, pre-
__
duce it is gut% a. issimnificaat amount that they are used priaarily only in the
? --laboratory.
- Section 18. Incandescent Lamps
The first incandescent electric lamp used for practical purposes was developed
- is-1873-by the prominent Retsina electrical eagiaver A.N.Lodygia. llis-laap-was-
F. the prototype of all the auccceZing designs of electric lamps. Iacaaideictat
-
S TAT
'1
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2 ?
??????????.
?
???
? It ??????`yr.ly.111 .":""-PINIIMMEMe , C. - .
..????????Tnea-CM.V*4-st
???-?????,????-????????#( ???,. r 1.1.????? ?
r?re.,??????+. - ..-?? ???????????????,1,1. qa????????.,.. ?? ? .???
electric lamps are successfully used as sources of infrared radiation.
The source of radiant energy in the incandescent electric lamp is a filament of'
Table 14
Characteristics of a Few Sources of Infrared Radiation (Bib1.4)
Source of
Radiation
Total
Radiation
Energy,
Energy of
Infrared Rays
in Region
?.
Energy in Diff.-."t Parts of
Regica 0.8-12 4, is X
vatt/ca2
0.8.12 A.
watt/curl
0.84.4
0
1.4-2.4
0
2.442 a
Mercury lamp
0.026
0.010
39
21
-
Tungsten filmiest
incandescent lamp
(gas-filled)
0.0125
0.007
3.2
20.5
51.0
Electric arc
0.034
0.024
12.8
54
%
Incandescent mantle
0.001
0.00077
5
63
20
Plug lamp
0.0007
0.000$
so
20
..
Helium lump
0.021
-
:7Z 100
j -
-
? pure refractory octal or cf refractory metal compound, a class including the car-
_
, bides, borides, and nitrides. Table 15 gives data on the meltine points of these
--materials. As indicated in this Table, the number of refractory pure metals aad
1
__refractory compounds used for making incandescence filaments ia relatively small.
The main characteristics for which a material for the incandescent filaments
of a lamp is selected are:
4t)
high melting point;
minimum rate of vaporization of
the filament;
ease of machining and strength;
spectral charecteristic of
the material, which determines the life of
a
radiation, as required for the lamp.
Of the pure metals, tungsten Lest satisfies
these
requirements and therefore
i _ 1
C- - is the principal material used for incandescent filaments of electric bulbs. Otlior
- refractory metals, such as tantalum, osminm, iridium, rlatinum, and sirocnium, have,
i..* . . _ __. _
- not found widespread use.
c.
a
Of the refractory compounds, tantalum carb.ade is most suitable for incandescent
_filaments and has a number of advantages over tiangstea. Its working temperature is
-1
Table 15
Melting Points of Refractory HetaLs and Compounds
Metals
ides m
Carb Wsturcsad
----
Nitrides
Usrides
1.4aterial
1 'M
Material 1 '1
Material I 1 'X
Material
...--
CU+112
3.1.73
tfaC + Pit
4215
TaC + laN
3645
HfB
1135
Tragstem
3663
41aC + ZrC
4205
M
Ike
ZrB
3265
PLeaium
3440
HfC
4160
TiC + TiN
3.505
Tun
3195
Tantalum
3303
TaC
. 4150
TaV
3360
lablyLciers
2293
ZeC
3305
ZrN
3255
amiss
2773
NbC
3770
TiN
3=0
Iridium
2622
TiC
3410
1341
3000
Zirconium
2300
SC
3140
Platinum
2044
SIC
3130
Marone
1823
UGC
2965
I Iron
1783
u?2c
mo
Nickel
1723
VAC
230
ScC
2650
SiC
2540
71 --440-50011 higher than that of tungstem, which isproves all the illumination parame-:
----ters of the loop. The rate of vcp,:rivmrien of tantalum carbide is about 30% lower
!F-- thaa that of tungsten, and the total radiation is about 3011 higher, which cor-
__
41:.__responds to as iscrease in Lrightaess of about 33% as compared via tungsten.
An obstacle to the wide use of tantalum carbide filaments is their low me-
--chanical strength.
4: Incandescent-lamp filmmeats are usually made in the form of a cylindrical coil
. ?bent into circular shape and placed in a plane perpendicular to the axis of the
-
5 =lamp (for a short filament), or in zigzag form (for longer filameats).
Gas tubes have relatively high thermal losses. Ohe of the methods of redeciag
-- these losses is
i4--------
sible only to a c.
c.
- - - ?
shortcaiag the coil and increasing its diameter, but this is pis-
_
a degree, since the strength of a filament decreases with is-
S TAT
aNair?e.J????????????Msaw.......?????? ????
???.?1???? MAUI .6.??Aare??
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Declassified in Part - Sanitized Copy Approved for Release ? 50-Yr 2014/03/27 ? CIA-RDP81-01043R002800190001-6
Declassified in Part - Sanitized Copy Approved for Release ? 50-Yr 2014/03/27: CIA-RDP81-01043R002800190001-6
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?
..4.'"?? ? ? 40, onr...????? were,.
AZ..% ?Ig.. ??,11..16/17.1.300eM..1101=..,..ar
_
creasing diameter. A solution of the problee his bees to deal,* filemests is the
.form of a double spiral. or"bispiral' (lig.12).
Lamps with a bispiral filament have a higher luminous efficiency this lamps
with Gni), ? single spiral filament. The increase is lusinous efficiency, amountieg
to 8-20%, depending on the type of lamp, is ez-
plained by the reduction ie the heat losses due to
the modified form of the filament. The grestest ad-
vantage is using a bispircl fill:scent is obtained for
low-power bulbs at 220 volts, ehich have the bigheet
heat loaaes.
In motion-picture projection, searchlight, aid
other special bulbs aid lamps. Ancandesceat bodies
minimum size of luminous surface are used. A filaseat
trl.t- io.4.03.5;l1=11,33:132Zlia
.....11174*-4,1111/4".
4
.144 `.? ? , ? ? tttp ?
-? 4
fr.4?
(Z?V
..was
Fig. 12 - rouble Spiral
filseent ("Bispirali
_ of maximum brightness and
- stretched spirally on a spherical or ellipsoidal surface, or a sphere or ellipsoid
of omapressed powder material, constitute typical examples of such incandescent
-bodies.
Vacuum
or gas-filled incandescent lamps with tungsten
filaments radiate most of
--their radiant energy in the region of short-wave infrared rays (cf.Table 14).
For example, a vacuum incandescent lamp, at a tungsten filament temperature of
- 2500.1i, has its maximum radiation in the region X . 1.15 and a gas-filled
__lamp, at a filament temperature of T 3000.1i, in the region X . 0.96 P.
40_
If the total energy radiated by a vacuma lamp is takes as 100%, then only
42..7-12X of the radiant energy is contributed by the energetic radiation in the visible
4'-portion of the spectrum, and the energy perceptible by the eye &scents to only about
The remainder of the energy, except for arall losses in the holders, is radi-
_-
4' -ated into space, mainly in the form of infrared rays.
The properties of tungstee incandeecent immps and the simplicity of their mass-
facture, permit their use as sources of infrared rays.
Table 16 gives as idea of the energetic balance of a 'scum incandeacest lamp
:4. _ .
- and of lamps filled with various gases.
(Th -
sad energetic parameters: aliment temperature, krightsess, luziaons flex, luminous
^
?
?
NEL MI6
. .
Cat of the sails drawbacks of incsadescest lamp*, as is other terperatere radi-
ators, is the very low selectivity of their militias. :ermine; the use of special
?
Table lt
nov1.114.8;66, of Faiivtion Emerry (is ptrceat) is Asrions
laczndenceat Lamps (MILS)
.IM???=??????........................,
1 Int of lis&stacs A warn
I lAwf
?.., 1
I Artornlied
i Lamp
Argos-Riled .
"Piarral' .
Law
Isne.04-Xesso
Fillet
ILop
Aiii/lerod4oLiva
Insra
-iile raa.athai
1 Lass ix ittlikra
1 ii,?....,,m .4......i. f.'s
7
86
a
1:2 _
+ .1
1
10
63
3
I n
1
I13
144
1 r.
2
12
7E
2
9
1
filters to cut out the required portion of the isfrared spectra*.
11
Section ly. Eaaic rev-meters of Inezmdencest Electric Falk
The iecamdesce=t electric hat is claracterixed 1., the followieg iilastaatioe
(-1
efficiency, power consumed, and 'Dorking voltage. Tae filament tempera-nre is the
mais characteristic deterwiaing all the illamisation-entiaeerrag aid energetic
parameters of the lisp.
Tae brightaess of radiatiom ia deterwiaed by the vorkiss filament temperature:
. the higher the temperatere, the greater the brightaess.
Table 17 gives data shoeieg the relation of fright:teas sad temperature. The
brightness iscneases sharply at a relatively small increase in temperatare is the
working repos of 2500-3000?K.
One of the main parameters claracterixisg the operatios of a Ion is the 11
acus efficiency, defiled an the ratio of the laaiacias flax to the total poser radi-
ated. sad measured in lumens per watt (leis).
The luniaous efficiency claracerises the ecoaomy of the lam or hall: the
greater the light flux radiated VI s lame per watt of poser impart. the more cools-
oaical the bulb will be.
$3.
4
STAT
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Declassified in Part - Sanitized Copy Approved for Release ? 50-Yr 2014/03/27: CIA-RDP81-01043R002800190001-6
?
*lb
../..11? reir.....neellgetlelenrini=".4, :
creasing diameter. A solution of the problea hms latm to desiga filament: in the
fors of a double spiral, or"bispiral' (lig.12).
?
Lamps with a bispiral filament have a higher Itnainous efficiency than lames
with only a single spiral filament. The increase in luainous efficiency, =entitle,
to 0-20%, depending on the type of Iswp, is ex-
plained Ey the reduction is the heat losses due to
the modified fano of the filaaent. The greatest ad-
vantage is using a bispiral filtseat is obtained for
low-power bulbs at 220 volts, which have the hisheat
heat bases.
In motion-picture projection, searchlight, and
other special bulbs and lamps, Ancandescent bodies
- 44,441.44461,tri""trrti?ilrat/A,s444"11
-.71T-41
%"Pj
I f..; 1.r.) 4--
4 t:1:4 t-
ic! t '
(1-te3.
Fig. 12 - rouble Spiral
lileasent ("Sispiral")
- - of maximun brightness and minimum size of luminous surface are used. A filaaeat
_
stretched spirally on a spherical or ellipsoidal surface, or a sphere or ellipsoid
of compressed powder aaterial, constitute typical ex:opine of such incandescent
-bodies.
Vacuum or gas-filled incandescent lamps with tungsten filaments radiate most of
--their radiant energy in the region of short-wave infrared rays (cf.Table 14).
For example, a
?T 25009k, has its
_lamp, at a filament
vacuum incandescent la=p, at a tungsten filament temperature of
aaxinum radiation in the region X " 1.15 t, and a gas-filled
temperature of T ' 3000"A, is the region X = 0.96 u.
If the total energy radiated by a vacuum lamp is takes as 100%. thee only
-7-12X of the radiant energy is contributed by the energetic radiatioa in the visible
-iportion of the spectrum, and the energy perceptible by the eye amounts to only abont
-3%. The remainder of the energy, except for mall losses in the holders, is redi-
4' -ated into space, mainly in the form of infrared rays.
The properties of tungsteo incandeecent. lamps and the simplicity of their menu-
(- :-7-facture, permit their use as sources of infrared rays.
Table 16 gives an idea of the energetic balance of a vacuum iacandeaceat lamp
- and of lamps filled with various gases.
(Th --
?
^
.? ? 'S ?-? ifefl.r-," yrwe Se.epthrleee? eres.ele......**e?sfeNre?resse.Selee ? ...ea..
Om of the masa drawbacks of I.candescent lamps, as is otter temptratere radi-
ators, is the very low selectivity of their radiation, reqeirisa the use of special
?
Table IC
ristriLttios of Psiistiss Ezerey (is percent) is Aerie's
lacsedesceat Lamps (!iILS)
-Inc of fisistics
A
irtax-Filleti
Lop
Anos-Filledkrre?,.vs-Xesso
'`Iiirpirala
Lisp
Ii lied
lap
Aisille rarlstias
IN-/Jr:tie rakiisv:as
Loss ix iriltiers
!......= .....T...?? mu
.....,
7
as
7
r.: . I
...-A,..,_,
10
fa
3
D
12
74
4
...
32
13
76
2
9
i
filters to cut cut the required portion of the infrared spectre:.
Section iv. Basic rare:eters of Incendescest Electric Falb
The incandescent electric hull is clarecterized ly the follemieg illuszmatioa
and energetic parameters: iilameat temperatare, Erighteesa, luziaous flax, lumiSots
efficiency, power comsumed, and working voltage. The filament Lerpers'are is the
male characteristic determiaing all the illumination-engiateriag and energetic
parameters of the lamp.
The brightness of radiation is deteraieed by the working filareat temperatare:
, the higher the temperatere, the greater the brightness.
? Table 17 gives data Showing the relation of 'rightness
and toopert!tatire. The
brightness inc-eases sharply at a relatively small increase in temperatare in the
- working region of 2500-30001C
One of the main parameters characterizing tbe operatioa of a bulb is the lami-
. _ eoos efficiency, defiaed as the ratio of the Inmiaoms flex to the total ;otter
mdi-
- and steszared in lemma per watt (1a/e).
( I:
The lmuisoutt efficiency claracurizes the economy of the larp or ball: the
granter the light flax radiated ty a lone per matt of poem, iapart, the more coat-
omical the bulk will be.
Fs.... sew ..........esoss??=e,emeesw.no awe ano.eslIelkgeSeeedeeWeseilt4460:"..."."4.4".""""'" 3"010.11061e0C44"......." ? ore a*,
-
?
STAT
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Declassified in Part - Sanitized Copy Approved for Release ? 50-Yr 2014/03/27: CIA-RDP81-01043R002800190001-6
3
...reemI????Yl?
ljeet...."4.*C? 4..h?.PErt,e9,.'rs ,
-
Ile values of the luxinous efficiency of vact-am and gas-filled lamps can Le de-.
termined froa the curies in Fig. 13.
Olen a lamp burns, the tungsten filament is gradually vaporized, and the walls
of the bulb are covered with a dark film, vnich attenuates the lusinons flux radi-
ated by the incandescent body. To reduce this harmful phenomenon, n11 modern
Table 17
Relation between Temperature aad Brightness of
Filament
Temperature of Filaneeut
ex
Stub
1000
0.003126
2WO,
20.7
2.5(.3
2415
. %a....
350(1
4540
36.55
6131
__- candescent electric bulls (from 60 watts up) are filled with nn inert gas (usually
, - a mixture of argon and nitrogen) which helps to reduce filament vaporixatios.
An stated above, an increase in temperature leads to aa increase in the ya-
36_- ergetic efficiency of n radiation &puree. Since, in g13- filled lamps the vorkiag
--
temperature of the filament car. be increased without shortening its life, the ad-
42
--vantage of charging a bulb with gas beetvaes evident.
However, this is true only for bulbs of medic= sad high amperage, which, as a
rule, have a relatively heavy incandescent filament. In low-amperage bulls, with a
-- fine incandescent filament, the temperature cannot be signifi-atly increased.
since this mould accelerate the vaporizatioa of the filament. Ile greater ditdi-
ameter of the filament, the higher the temperature it can vithatcad.
Consequently, for lamps at the setae feed roltage, the luainous efficiency and
filament temperature are higher in the higher-amperage lamps. The variatioa of the
pareaeterkotincandescent lamps with applied voltage is shows by the curves is
fit. lit._
4
a
Section 20. features of the tesirs of lacendescent Leap for Searelligits
Me principal differences betseea
lamps lie Is the fors
loll.
The selection
searcilitht ramps and ordiaarv
of the incandescent
of the tie of
1
1 ; !
;
.1 7T1-1
r2,-4-4.6.1 I I
it I
i
!i; Jill I
C0117 6 4
fig. 13 - Felatioa of 'Lm.nanceas Ef-
ficiency and Temperature:
1- For gas-filled laa;ss with
tmagstes filament; 2- For
TaCCUM lamps with ungsten
filmiest
a) luminous efficiemcy,111./111;
1) Teepereare,
body and tie fors and disettions of tie
lamp 11 dettraited
3154
.PC1
the dives:ions of 'le :ens
Fig.14 - %gristle* is tie Nraceleis is
%) of Iacandesceat Lamps as a functioa
of Noftage Isput
Luminous flax; C-CL- 141111421-04211 ef-
ficiency; 4- Power; Carream;
Fesisteace
a) Apphe4 wm3tage, welts; 1) F;
c) Emrstiaa of laraiag
system of the searchligt and by its purpose.
Figure 15 shoes characteristics modem searchlight lamps. Py filamest fors
sad boll slave. mach :asps
any be malady classified iato four rromps.
- The lamps of the first grttap (fig.15.a) have a crlisdricai spiral filament of
small dirweter-let relatively great leagth. The aais the spizal is perpeedicslas
to the axis of the lamp, sed he shape of the lull ss miasma/ spherical. This posi-
?-??? ?????1* ???????????..S
- ?
STAT
Declassified in Part - Sanitized Copy Approved for Release ? 50 -Yr 01 /
a
Declassified in Part - Sanitized Copy Approved for Release ? 50-Yr 2014/03/27: CIA-RDP81-01043R002800190001-6
r,
a
a
. v-sr.unat-oritrsmt ?
tion of the filament allows a small angle of diffusion --1 the vertical plane and a
large angle in the horizentul plane to be obtained from such lamp in a searchlight.
....----,.
..---------... ?
_ -
,./. \
i
/
t-a.: '
0 i t i I r"tj ! I. Atil i
\-
..,? ???1 i
; 1.? 4 ? ?
I I
}
?..... r-- ???-r i ri 1 I c-,',.: )
.,,,....Lii
Li
,rree
9 cl)
Fig.15 - Types of Searchlight Incandescent Larp.
In Imps of the second group (Fig.15,t) the incandesceezt filament is the same
-
as in the lamps in the first group but is installed along Che axis of the 'sap; the
shape of the bulb is spherical. In using larps with such a filament, Che utiliza-
tion factor of the lens system of the searchlight is increased.
'
To increase Che efficiency of certain projector lamps, Che front surface of the
?/ - spherical bulb, is coated with a mirror layer serving to direct Che luminous flux
---1
--from the filament into the lens system of the projector.
- In lamps of the third types (Fig. 15,c), Che spiral filament is arranged in -rig-
3 !:
--zag in a single plane (which gives the incandescent body a rectangular form) and is
? .
--placed in a bulb of cylindrical Shape. Such a filament form allows the necessary
--tangles of radiation in Che vertical and horizontal plane to he selected by varying
4 : a
--the ratio between the sides of the rectangles.
In Imps of the fourth groun (Fig.15,d), the incandescent filament is draws
out in the form of a spiral. The bulb is cylindrical or has a spherical bulge at
-the center. .
Table 18 gives the main design, electrical and illtuz.nation-engineering data of
a few types of searchlight and motion-picture projection incandescent lamps. The
_ range of voltages is from 11-221 volts, and Che range of power from 250 to 3000 watts.
(1
S
a..
J.
4.5
^ ;
r )
C
.44
Proj pot I on
W
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1.
a.
-
...: _
g
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TS
f.',
0 0 0
0 0 Cb
al. .???? 41. 0.1.
g 8 8 g
I gg
... :
...? -.. ?
s ,.. ....
Z 3 A
1 1
.7.? -
- .
.4 14
li.
*
... ? ai
... g ...?
? 4:4 .?
l a ...
.
=
c...
4
S 4.
1.-
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61
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t? .0 C V. p
... ?
... et it- r.
La ?? i .?
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...
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T.%. C.
... -. ...
g ...
r ..
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TV
.?
4
44
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?
--
TV
ri
r.
rg = g-
IV TV r. re r?
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4 0- .... ...:
re ... r 1 e.
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an ,-, v
r.: ....-: r; .i? ?;
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irZ sr! .1; r.;
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t.1
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r
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a. ?-?
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aff
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at
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C. 4 4; ...; .4'
0.? .. .??? .s, ....
c? ?.. s? gg
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31; 4.
ell
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or
ilt
a
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ar.
a ..., WS
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c. ... 4. .... 4
... CO 44
42 .44

ro ... go. aag
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re ... ... ...
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ST
STAT
Declassified in Part - Sanitized Copy Approved for Release?
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/03/27: - DP81-ninzvlpnn
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Declassified in Part - Sanitized Co .y Ap roved for Release ? 50-Yr 2014/03/27: CIA-RDP81-01043R002800190001-6
.3
?ir-tro-orb_
state, bah a vent high resistance aed-thcrefore cotdwcts almost os curreat, the
uver-all brightness ranges fro* 455 to 3000 atilbs. The forns and types of the
sockets vary (according tw the function of the leap).
The life of the lamps shorn in Table 18 corresponds to nem,' voltage conditions.
By shortening the life of the lamp under forced conditions, the laops will yield 6
higher luminous efficiency and brightness, which sometimes excee6 30O0-460D stills.
Section 21. Special Infrared Radiators
The Pod Lamp
The idea of designing a lamp with a luminous body csife of a kaolin p1c.te, heated
to incandescence by a current. was conceived by the femous bossier, --_-ientist inven-
tor, P.N.Yablockhuv.
Figure 16 schematically shows the construction of the rod lamp in which the
Fig. 16 - The Pod Lamp
54 !, !
? II r
72
?
to-1 I Aa. I I
b
6
4
2
1 ;
i!if)i
t 23 b 5 6 7 itO
a)
Fig.17 - Radiation Spectrum
of the Pod Lamp
a) tavelength, a; L) Inten-
sity of radiation in relative
units
incandescent body is a compressed cylinder, the rod R, made of a mixture of zirco-
nium dioxide and yttrium oxide.
The diameters:if the rod is 0.4-0.6 mm, its length 12-20 am, its supply voltage
100-250 v, its current 3.25-1 amp. In view of the fact that such a rod, in the cola
cllinder is prehetted ty the incandescent platisum *ire c, mound oft the percelaia
pia A.
After preheating for 30-45 sec, the resistance of the rd is consideraklm re-
duced. In order to lixit the increasing cmirest, te rIsistor P is connected is
circuit of the rod.
The electrocagnet I serves for automatic smitching of the rod from the pre-
heating circuit to the working circuit with the resistor P.
The radiation spectrum of the rod lamp (fig.17) las tao principal marina, one
the
in the reFir,o 1.6 mnd the otler in the region 5.5-6u- Tie rod lavp is a
. .....
.
111
11111116111116-
Ird1111111
.....
In
1111111111111
0
,..._L.,_,%
I
2J.
,
RIMININ
567
8
5V:1110,4
a
Fig. 15 - Spectrma of Pmdiatino of Imcasdessent Wamtle
a) lavelengti, 1) Iatensitv of radiation, '4
f230,3
selective source of infrared rays, 1st at the sane tise has the follosia, -Raiz dis-
advaatspes:
Seetsitivitv to floctcaticos is voltage, requiring stalailizatice by IICA2S of
a larretter;
Low radiation power, allosrimg the rod lamp to be used primarily only wider
lakoratory conditions;
rapid disittegratioa of the rod witk racreasing temper-stare.
/he Incandesceat Vaatle
IS its &SIM, this mantle coasists of a cap beat441 to incandescence 1m as
flame of a livi4 fuel or iaa.
The body of the xastie is made of silk impregnated mitk thoriaa oxide, Midi a
fee percent ceriva oxide aided.
59
'
STAT
Declassified in Part-Sanitized Co?yAp?rovedforRelease ? 50-Yr2014/03/27.CIA-RDP81-01043R0028001gorm1R
Declassified in Part - Sanitized Copy Approved for Release ? 50-Yr 2014/03/27: CIA-RDP81-01043R002800190001-6
a
. ? ?a se. I I a !! I! =,1 ft. ? *IT r WI I I .1' ?
_
A feature of the incandescent burner is its radiation over a very wide range
of the infrared region of the spectrum, beginning from 1 it (Fig. 18) up to 100-150 p.
Because of the !ew intensity of its radiation, however, the incandescent maetle is
used only for laboratory studies.
_ Section 22. Electrolueinescent Radiators
Ahile temperature radiators yield a continuous spectrum, electroluminescent
eources of radiation have a discontinuous line or Land spectrum. Electroluminescent
Table 19
Atonic and Electrical Data of a Few Gases and Vapors
Gas
Atomic
Number
-----------
Atomic First Pesaonmsce
leight. Poter.tial, ?
Ionization
Potential, ?
Hydrogen
1
1.013
_
13.53
Helium
2
4.002
19.77
24.48
Nitrogen
7
14.008
-
14.48
Oxygeno
...
16.0
-
13.55
Neon
10
20.18
16.77
21.47
Sodium vapor
11
23.0
2.1
5.12
Argos
18
39.94
11.57
15.69
Mercury Taper
Bo
200.16
4.E6
10.38
radiators make it possible to build high-intensity selective radiators with a maxi-
mum of radiation in a very narrow region of the spectrum, depending on the gas used
for filling.
Electroluminescent radiators have a number of disadvantages: the relative com-
plexity of their circuits, which requires the use of chokes and transformers; the
considerable time required for establishing a steady state, etc. These disadvaa-
tages limit, to a certain extent, the use of electrolusinescent radiators as techni-
cal sources of infrared rays.
Electroluminescent radiators of the type of gas-discharge tubes and gas-
discharge lamps are being used widely in infrared technology. In their desiyu, ra-
diators of this type consist of a glass or quarts bulb filled with gas or with a
vapor of certain metals. Metal electrodes are fused into the Lull), and the voltage
necessary to produce a discharge inside the haat is applied to them. The construc-
tion and design features of various gas-discharge :amps used is infrared technology
will be considered below.
Section 23. Cases and Vetal 1sals Lied for hIliae Ges-Cischarge Lamps
The following gases are used for filling gas-discharge laaps: neon, helium,
argon (as an additive), and the vapor of mercury and sodium. Sc,dium vapor is chem-
ically active and reacts al.th the glass of the laup hells. Since the vapor pressure
ra)
11 L
ii
rrc
...... -.4.
f)
Arif
44'
co
---t-
0Li
Fix. 19 - Volt-Acpere Characteristic
of Gas Eischarge
a) Current, amp; b) loltage, v;
c) Arc discharge; d) Aoonaloos glow
discharge; e) Normal glow discharge;
f) Transitional regions; g) Silent
independent discharge; h) Silent
non-independent discharge
g)
h)
of sodias is the pure state is very low
0.0002 rm Hg), a certain =cunt of Leos,
argon, or other inert gas slick is atomical-
ly inactive end does not combine with the
electrodes and the glass, nart be added to
obtais the discharge.
Mlle 19 xives the atcnic and electrical
data of a few gases and vapors used to fill
Ems-discharge lamps.
Section 24. Forms of Discharge is Gas
The most convenient way of stsdyisg dm/
various loran of electric discharge is a gas
is by plotting the volt-ampere characteristic
of the gas diLcharge, as shoat' is fig.19. /
This diagraa stows that, for the initial
section COL direct proportionality betsees
current and voltage exists. The subsequent voltage rise does not lead to aa is-
crease in current, and over the segment AE the curve runs almost parallel to the
abscissa. A further rise in voltage leads to as increase is current along the seg-
ment BC. Taken as a whole, the region OC is called the region of silent Dos-
independent discharge.
The segment CG is characterised by coostast voltage vitt rise of carrevt. Along
? . .
61
STAT
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,
the segment DE, a voltage drop occurs, while the region CE is the mane of silent
independent disenorre.
Along the segment EF (in the
transitional region) the vo)tase drops rapidly,
the current increases, the gas in the
:2345 1 7
I//If
20 - Electrical and Labdoous
Characteristics of a Glow Dis-
charge in a Gas-Discharge Ube
I- Cathode dark space; 2- Pegion of
cathode glow; 3- Non luminous nega-
tive dark space; 4- hegion of nega-
tive glow discharge; 5- Faraday
dark space; 6- Positive column;
7- Begion of anode glow; 8- Anode
dark space; a- Gas-discharge tube;
b- Intensity of luminescence;
c- Distribution of potential;
d- Density of electron flux
voltage applied between the anode and
Imp begin: to glow, and a nomal glom dis-
charge forts in the region fG (where the
current does not depend on the voltage). A
further increase in current leads first to a
sharp voltage rise (up to point H), and then
to a sharp voltage drop (up to point 1), and
in the region GI an anomalous glow discharge
takes place.
The last region, IJ, in which an arc
discharge occurs, is characterized iv high
cv...:Te-,t and low voltage.
The gas-discharge lamps used as sources
of infrared rays usually operate under glow
or arc discharge.
Section 25. The Glow Discharge
The gas contained in a gas-discharge
lamp is always in a state of paltial ioni-
zation due to the action of external ion-
izing forces: ultraviolet, radioactive, and
cosmic radiations. Under the actioa of
cathode, the electrons heels to he displaced.
In addition to this electron ccrrent there also appears a current due to the posi-
tive ions moving in the direct:oa of the cathode. As a result, the total current
increaaes. For a glow discharge, low current density and great voltage drop are
characteristic. Such a discharge is Characterized Ly a Iright glow, shoat color is
determined by the kind of gas in the lamp.
.31
Figure 20 shows the electrical And Inaiscvs characteristics of a aloe discharge
IA a gas-discharse Laic.
Figure 20,a shows that direct/v at the cathode (h) therl is a narrow resins (1)
called the cathode dark spate. This is adjoised lv the tepien cf cathode slow (2),
followed ly the region of oosivinisous regative earl zpez;es 12). ise negatiie i.irk
space is in
turn adjoined iv the region of negative glow discharge (4), paaiisg over
into the faradav dark space (5), which 21 Vi.rl! changes over
inn positive colunn (6), terxinating is the region of anode
the anode A EV the narrow anoCe dark space (E).
It will be clear fros fig.20./ that the izteasity of lanizescerce is iiitri-
hosed oonuniformla alone the leap. Is the region of the ca0-_reLe earl space there is
no lonizescence. Is the region of the cathode rlos there is a snail maxima: of
in-
tensity, diainishing on traoaition to the reeion cf the iteratile earl space aid
again sharply rising ia the region of nerativi: glow discharge. Is the :epee of the
Faraday dark space, the intensity of luminescence dropa sharply aid thee rises grada-
szto tie irightly slow-
rico (7), separated fro,
ally, assuzazg a constant value is the regica of the positive colauva. The anode
rlovi has a snail mamizmn of intensity and then fans is tie anode dark space.
The potential is also distrilsted irregularls let:seen the electrodes
In the region of the dark cathode space there is A cathode potential drop. Is the
region of the regative glom discharge there as a sexless of potential, Which de-
dines first is the region of the Faraday dark space ad thee smoothly rises almost
to the anode, where a small upward lamp of potential is suted-
The demaity of the electron flax (fig.2).d), legienizs from t_v! cathode, risen
gradually to the regioa of the Faraday dark space Acre a small ea:imam occars. aid
them remaias unchanged almost to the anode. *here it increases slightly.
Section 25. Helism Lamps
,
The helies gas-discharge spectral lamp. Which is a resonant s.ocrce of lairared
revs, is schematically slows as Fig.21. This lamp differs is design froa ophsary
gas-discharge toles is that its hal% 000taiss a special cepillary tale in which a
STAT
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Declassified in Part - Sanitized Co .y Ap roved for Release ? 50-Yr 2014/03/27: CIA-RDP81-01043R002800190001-6
?
?
4/. ??????rowlaursaverm=rwit=z-z-t
current density of 500 sap/a.2 is reached.
The }.rightness of radiatiun of the helium lamp is up to 600 ab, and the aaximum
radiation is in the regio u 0.8-1 4, i.e., is a source of near infrared
Fig.21 - Diagram of Helium.
Lamp
?
to
a)
6
0
rays.
la IA 2 44 2,1 3,3
b)
Fig. 22 - Hadiation Spectrum of a Helium
Lamp
-) Iut-r.=;ty el ;- scletime
units; b) lavelength A
In 1934, Ye.Devyatkova and N.Devyatkov developed an original type of helium gas
discharge lamp (Bib1.6). The tube is made of molybdenum glass. The anode and
cathode are located at the ends of the tube. The cathode is made of oxide-coated
tantalum,
the oxide
and has the form of a cylinder, within which a tungsten spiral for heating
layer of the cathode is placed. The helium charge of the tube is under a
is 40-
pressure of 4.5-12 mm Hg.
The voltage required for a discharge to occur
90 volts at a current of 2-12 amp.
The radiation spectrum ofithis lamp (Fig.22) is mixed. Together with a strung
resonance line of helium at the wavelength 1.011 0, the spectrum haa a continuous re-
gion of radiation of the incandescent cathode in the range 0.8-2.95 4, with the maxi-
mum of radiation at 1.8 IA. Both types of helium lamps mey be used as radiators of
short infrared rays.
Section 27. The Cemium Resonance Lamp
The cesium resonance lamp consists of a bulb filled with cesium vapor. Inside
?
ant
4
_ .
the bulb is Attached a tube with electrodes. The Imp is a selective source of near
infrared rays of great radietion intensity is this region. To previmt the destruc-
tion of the glass due to absorption of cesium vapor, the inner surfame of the bulb
is coated with a thin layer of a special composition. The lamp is rroduced is 50-100
and SOO watt si?es.
The 100-watt lamp (fig.23) cossists of '.he tube h . 125 cm long amd 35 um in di-
ameter, filled with cesiun vapor and some inert gas, such as argon. The tube cads
in the bulb B, 50 Ea in diaaeter, one end of which terainates is
the four-pin plug
The discharge takes place betm,eo the two spiral tungstee
electrodes E coated wies barium and strontium oxides. The dis-
tance between the electrodes is 76 um.
The fact that the tube is filled with argon with an admixture
of hydrogen (0.0061) facilitates ignition and iacreemes the is-
11.? Aft
- vi.m4ma
of 100-latt Cea- of 200 em Hg, the lamp his
imm lamp
tensity of the Immisesseece of thm mmm.Imm
its maximum resonant radiation in the
region-of the near infrared rays. With decreasiag pressure, the
resonant radiation dimieishes, while with increasing pressure it shifts sato the
-visible regicm the spectrum, and rle burning of the lamp becomes unstable. fig-
ure 24 -Items the radiation spectrum of the cesium lamp. The nazism' radiation of
the lamp corresponds to the wavelengths 0.86 and 0.89 P.
A 100-watt cesium lamp has a power output in the infraem4 region of the spec-
trum equivalent to the output of a 700-watt incandescent lamp.
The cesium lamp has the very valuable property of permitting almost complete
modulation of the cutrent. The aodulatioa characteristic given is Fig.25 shows
that the modulation percentage, over the greater part of the audio-frequency raage,
is 901 and,at 10,000 cps, amounts to about 60-709.
A 60-watt incandescent lamp is also modulated by an audio-frequeacy current up
to 6000 cps. In view of the great therual inertia, its perceetage uodmlatiom at a
frequency of 1000 cpA is only a thousandth as great as is the cesium lamp.
?
65
STAT ?
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Declassified in Part - Sanitized Copy Approved for Release ? 50-Yr 2014/03/27: CIA-RDP81-01043R002800190001-6
? ?????????,
I???????
?
44. 4...4 'Vs .11 .1,4114-41?4.7.4441.????=_ ?
figure 26 shows a wiring diagram of the cesium lamp. llt tungsten electrodes
are heated to incandescence by current from the winding of the transformer 12 1.46 mep.
r) for one minute, after which a discharge takes' place beteeen them. The
I kV
$.47
a)Id
-1
--t I ..,..s1
1 i 70 ?
?1. ?-.1 ;
t
i 1 :1 %
4-4i ,301-1.
I
to
W M.10
katt al
go ?????? ??????? Owe
?
I ;
C..% ;Ea 17Z C4
a)
!IAA C:a
tig.24 - hadiation Spectrum of the
Cesium 'Amp
a) Wavelength, ti; 1)) intensity of
radiation, %
tXr..:1X
Fig.25 - Modulation (laracteribtic of the
Cesium Lap
a) Frequency, cps; b) Percentage sodulation,%
300 vat: ultcrnating current for the pewee supply of the lamp are fed frma the
starting treL-efer=er 12. After iga: - -- of the lamp mod after it has burned for
Fig.26 - Wiring DiagTrA;n of/Cesium Lamp:
12 - Starting transformer; M - Modulator; L - Lamp; C - Capacitor
of modulator; T2 - Transformer of modulator
a) Direct' current
one minute, the DC voltage is turned on and the current drops. Then the 300 volts
AC and the heater voltage axe turned off; IS minutes later, the discharge in the
lamp becomes steady (steady state), and a modulating voltage can Le irposed on the
lamp across the transforner T1.
aaa
1*. ...mew. Jo aor e. ? r ??????????????,?
Section 28. !,15..a_uryELam
.4,114:114,
44.4444444 4:4,4 ,4 .4 4.44 4,4 4. ? ? ? ? 4 ? 44.? ?
?
Mercury lamps are widely used in various fields of spectroscopy and iafrmrtd
technology. The first patent for a mercury lamp (low-pressure) was issued is 1879 to
1----1-- I ?
1 -t
1.---1 i ''? 7.-1-17-*,--7.1 t I
a: ii i ; :14 i 1 i
I
oii, - I i Vi if
!fig
.-.1
1. i I
t) la
i ..Z ! 1
4114
'4 iti " f i
11 ' ;--c ,?? ?.,, 3
ea St 1,1.; i R..
1.;:, if & 1
f I -111
&A C.5 c.1) ors. it "..%.11:,,?----j,
Fig.27 - Eadiation Spectrum of *.anGAt!-2* Type Vercary Lamp
a) Warcleagt'a,..; b) Intensity of radiation ia relative units
% *
the Bussiza scientist Professor Bep'yew.
The arc dischzrge in 'ternary vapor has certain peculiarities By cospatison with
the discharge iA other vapors.
In mercury lisps, together with as electron cnrrent: an 'os correat passiag
--from anode to cathode is generated. The density of the electrom and ioe currents
depends on the velocity of the electrons and ions.
Since the velocity of electrons is considerably higher, the density of the
electron current is also higher than that of the ion carrent. For this reason the
total dischsrge cam-rest of the mercury arc is determised primarily by the electron
curremt.
With increasiag carrcat density, the nuaker of repeated collisions betimes the
stoles, as well as their energy, increases 'stepwise or, as it is comonly ex-
pressed. "stepaise iccitation" takes place.
tor leaps aids elevared pressure, the phenomenon of concentration of a
nous discharge discharge colcan is characteristic - its constriction late a narrow "thread'
of very great trightAess ("threading").
?
'
_ -
57
? ..????70*?.....0????.????? ?
;
S TAT
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Declassified in Part - Sanitized Copy Approved for Release ? 50-Yr 2014/03/27: CIA-RDP81-01043R002800190001-6
.? .
on.. .168.? 877. ?
e 0..-011a ? ft ? .0 oo
Depending on the pressure of the mercury vapor filling the lamp, there are three
forms of mercury-arc discharge, at low, high, and extreme mercury-vapor pressure. la
this connection, mercury lumps are subdivided into limps of low, high, and extreme
pressure.
At low mercury-vcpor pressure, not exceeding a few millimeters Hg, and low cur-
rent density (nboet 4-5 amp/cm2).
region of the spectrum.
the maximm radiation occurs in the ultraviolet
Table 20
Distribution of Radiation Energy over Spectrum of Low-Pressure
Mercury Lamps (Bib1.7)
...
Power Input
Xatts
43ectra1 Distribution of Radiation &err/. X
Lltrariolet Region,
0.2-0.39 II
Visible liegicm
0.V-0.75 il
infrareii fleajten
0.7E-4 it
250
29.9
54.5
15.4
I
300
30.9
52.3
1G.8
350
33.5
51
I 18.6
400
29.9
Cit.* 14.4
At high mercury-vapor pressure, the current density and concentrations of atoms
and ions increase. Under these conditions, the phenomenon of threading of the dis-
charge column tikes place, and the resonance lines of radiation in the visible re-
gion of the spectrum are intensified: the yellow lines at wavelengths of 5791 end
5770 kand the green line at 546e A, as will be seen from fig.27. which &ow* the
rhdiation spectrum of the mercury lamp.
At extreme precsure, the current densiLy is still greater, and the radiation
in the infrared region of the spectrum increases.
Consequently, depending on the form of the discharge, the distribution of ra-
diation energy over the spectrum also varies.
Table 20 gives data on the distribution of radiation energy over the spectrum
of low-pressure mercury lamps.
Figure 28 shows the spectral distribution of radiation energy of three extreme
-
pressure mercury lamps, 4.5, 2. and 1 em in diameter, respectively (Fig.28.a.b.O.
\-
at respective pressures of 20, 130, and 200 ate and potestial gradieuts of 120. &II,
and 600 watt/cm.
The curves are plotted from trie data of xessarenents (BiLl.7) anti show that
with increased pressure the lite r.pectram changes
sic
!t
20.--
a ?L
A.7a
ii
into a continuous spectrum.
SI i1
d'213
t 1
"ir 1 IF ---1
45 0.7 ittNuttts-:
1,5 z4 (p.)
!
z,t
1 Ifi
45
v
Ai
20
le
I lIl
il...
0,5 0.147 22,Z (1s)
OA 1S47 I 2U (p)
Three Extreme
fig.28 - Spectral Distribution of hadiation &ferry for
Pressare Yercary Lamps:
a- Diameter of limp 4.5 ma pressure 20 atm, potential gradicat 120 watt/cm;
b- Diameter of lamp 2 am, pressure 130 eta. potential gradient sae vattica;
c- Diameter of lamp 1 me, prcammre 200 ata, potential er=4ie.,at E00 watt/cm
1) Eadiation energy ia relative units
Table 21 gives the spectral distribution of radiatioa energy (is 8) of extreme-
pressure cercury lamps.
Extreee-pressure leaps have a high efficiency.
For lamps at 200 eta pressure, the total radiation power amouots to abos? 75%
of the poser input, shich indicates the great economy of the lamp. At a lual.cous
- Immahsa lowloa????
69
-
STAT ?
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a
.0444?4?4.1???
8.4 044.4. .06.????????? le? 111,10?? .71/.. ? IMMO* St IP
?
efficiency of 65 1m/watt and a power input of 710 watts, the lamp radiates a flux of
46 :4 103 1m. TO obtain a similar flux from a tungsten incandescent lamp would take
-
Table 21
Spectral Cistributiom of Radiation Energy of Extrene-Pressure
Mercury Lamps (Ribl.7)
Lamp CatsSpectral
Luminous
CI:tribune* of Brabant Energy.%
Dir.?.--zter
MN
Gradient. 1
int tja?
Pressure,
stem
Efficiency,
la/watt
X < 0.4i
X . 0.4k 0.7 '.1
X >0.7 A
?
.?..
4.5
120
20
40
45
l 22
27
4.5
135
20
48
46
26
23
2
F..00
133
S6
40
30
1
30
1
800
2'00
65
31
35
34
1700 watts, or 2.5 times as much power.
Sith increasing pressure, the radiation power in the infrared portion of the
spectrum also increases. At a pressure of 200 atm, it reaches 34% of the total re-
diation of the lamp. For this reason extreme-pressure mercory-arc lamps are
radiators of short infrared rays.
Section 29. Extreme-Pressure Mercury Lamps
fec4
According to their design, excreae-pressure lamps (SND) may be subdivided into
three types: capillary and spherical with natural cooling, and water-cooled capil-
lary.
This classification is based on the operating conditions of the lamp. The
brightness of the radiation of mercury-aro lamps depend: on the power consamed. This
power is limited by the heat-resistant properties of the bulb, which is made of re-
fractory quartz glass.
Extreme-pressure capillary mercury lamps with natural cooling are desigme6 for
a pressure of 20 atm and a power of 40 watts.
The capillary mercury leep consists of a qc,:i-tz capillary tube, of 2 is inside
diameter, 6 is outside diameter, and 35-40 is length. Two tungsten electrodes are
inserted int, the tube at the ends, and are separated from each other by a distance
1^?
aot exceeding
presture, the
0 0
:At ? .0 0411,..4.4o4,44..4.4444
30
is. lhe take is filled with resolve. vapor. AA a rennIt?Cf'tie Li*1
discharge column is the tab.: of the lamp is ddrzaa
a.%
! , ?
.. ,
? I z
?,
( 1 .4? 4.4 } I
t t
? :?????
isto a narrow thread
C?4 4.50.:-72,1411 V 35 V
Fir.29 - Dadiaticm Spectrum cf a 5IE-250 Wercsry Law
a) Vavelenstl,..: h) intesaity of rad:a:rote is relative
"its
of a diamet.r mot over 1 is, thanks to which the hip Erightaess of tie raliatica is
obtaiaed. firsre 29 sl=us the spectris of radiative of the S8E,250 !sap.
-Me spherical leap (fig.23) consists oi a spherical quarts ban of IQ ma out-
side diameter sad 4.5am isside diameter. The length of the tale is 43 is. mid the
distasce between the electrodes IS am. Special spirals placed on the electrodes axe
ased for heating.
At am emergy
coaswmpcioa of 70 watts, the lamp has a Immisoms
Fig.30 - Air:seem/est of a Sit: SOherica) Lamp:
V- langstea electrodes: Q. Spirals cf oxide-coated critgsrem: A, cmarta
Eulb; V- Volyidesum foil; P- Coatacts of electrodes
efficiency of 90 isffistt.
Tale 22 gives 0-..e paiaaeters of capillary and spherical extreme -preasmre
'4-4 ? ? 4{.. 410 ?4?.4.44.4146. ?111.,4..44 4444.6a *dn.*. ...1.m? ....2444.14?????4 .4?44.44.44.
71
I
...A.A.... 41 4 M
STAT
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Declassified in Part - Sanitized Copy Approved for Release ? 50-Yr 2014/03/27: CIA-RDP81-01043R002800190001-6
?
,
???-?arNEWIllaleilISZT?2111=...-?4" :
mercury lamps with natural cooling.
The water-cooled capillary lamp is a quartz tube 150 mm long, placed in another
quartz tube serving se a jacket for the coolant voter. Trvile 23 gives the parameter
Table 22
Parameters Gf Super High Presaurt Nsturally-Cooled Cspillary and Spherical
Mercury Lamps (Hib1.8)
prImINA.M
Type of Lamp
Ignition
Voltage.
Working
Voltage.",
Correia,
Amp
Power.
Watts
tteat-lp
Tine. min-
Prigitaans
SU
Lmiumm bminaue ILA"'
Flex. Inlifficiaacy. Boers
la/watt 1
Capillary
Some
190 115 0.4-0.75 80-100 4-6.45
1500-2000 1250-1E00 0.5-1.2 1000-1%0 3-5
4herfeal
70-90 6 r,o-sto I10
1100-2000
15103-3000
10,000-
25.000
3000-340
40.000-
15.000
12,00?-
20. 000
500
38 500
100
of these lamps.
Section 30. Basic Data on the Theory of the Arc Discharge
Before dirt:Lasing arc lamps in which the source of radiation is an electric arc,
we will present basic information cn the theory of the arc discharge.
Table 23
Parameters of Super-High Pressure Capillary Mercury Lamps.
later-Cooled (Bib.!)
a b cd
e f g I h i j k i I me
SP-.500 12.5
2
6
75
500 1.5
1.3
420
30,000
33,0(0
60
500
SP-800 10
1
3
120
800
1.5
1
1.3
600
50,000
91.000
1
62
25
SVCV
1
6C,C00
1
-
60
-
(MELZ) -
1
-
-
101
1000
1 5-2.0
1 -
600-800
a) Type of lamp; b) Length of chschargeomm; c) Inside diameter of tube,;
d) Outside diameter of tube. mm; e) Mercury-vapor pressure.atm; f) Power cow-
somed, watt's; g) Value of current, amp; h) Current. amp - AC; i) Current. amp
DC; j) lorking voltageor; k) Luminous flux.1m; 1) Maximum brightness.sh;
m) Luvlinous efficiency,Ww; a) Life. hours.
An arc discharge develops from a glow discharge when the current dtasity is is-
-
OM.
?
(, ? _
creased to a value sufficient to heat the cathode to a temperature az which mission
-
of electrons begins, i.e., at which thermoelectronic mission occurs. The high tem-
perature is maintained ly the lembarthient of the cathode with positive ions. This
form of discharge, called the therzal arc, Ls otserved is
electric arcs.
If the cathode zarerial has a low vaporization
perature (for instance, serourv), then vaporization takes
place Lefore the temperature necessary to start electron
emission is reached, and at a certaia pressure, a discharge
occurs rith a cold cathode. This in esplaiaed by the fact
that the mean free path of electrons at high pressures is
very short (about 10-S ca) so that ionization takes place
positive space charge, formed as a result,of ionization, is
FIK-t?--17, I
I I I
1 ti 1.7 -''.:slf q 1
fig.31 - Eistritutioo
of Potential ia an
Arc Eischarge
around the cathode. The
teas-
concentrated at a certaia distance from the cathode, equal to the wean free path of
the electrons. This space charge, tomether with the electrcima,
layer with a potential gradient reaching 10-144 watt/ca. The discharge taking place
is called an autoelectronic arc, or a cold-catheie arc.
figure 31 shwas the potential distrilotion is various parts of the arc.
The catLode-potential drop U/ is relatively small (10-15 v), which distiaguislies
the arc discharee fres the glow discharge, is which the cathode-potential drop
reaches 250-200 v. The length of the seg2ent of the cathode-potential ere, it for
. _am arc discharge in negligibly sad', al:meter thee the wean free path of the elec-
trons, which, for a carbon arc is air, is 0.01 mm.
seer the ancde, on the segment Ll, the anode-potential drop CA is formed. The
segment hetweca the regions r.f the **ode and cathode potential drops is called the
luriaous, or positive, col. Is electric arcs, this segment is occupied 17 the
flame of ti..e arc. The potential drop CL is the region of the positive colsmn varies
by a linear law.
The total potential difference letween the electrodes of as arc is determised
as the sus of the pnteatial drops over the individual segments:
?
?ffia.6* ?
73
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0
Declassified in Part - Sanitized Copy Approved for Release ? 50-Yr 2014/03/27: CIA-RDP81-01043R002800190001-6
?
- ?
? ? ?..-- .... .. ..... -. . -. . ... .4...4. n. ?sr ???-st ?gray Nomg..? ?",=.1.tart;._^
-- . --....? ? ? . .. - Ix...* - ? i .1`.."-^vrt^' "" ... ' ; ? ' ,N P"-....4 ',..4-4+4 .....J.,C.40r,.. . ,.--?*-4.,-, r--?.-. , ? ???? ,t., ,, ....,, 4r,, ??,..? t ...r..-1.,,.????*,????????????????? ? ?
U.T. a DIE + UA UL (101)
Let us consider the various types of arc lamps.
Section 31. The Simple Electric Arc
The electric arc was discovered in 1802 by the famous bussian scientist Proles-
soy V.V.Petrov.
Figure 32 gives the diagram of the simple arc. The arc discharge, or arc, is
formed between two carbon or graphite electrodes. The cathode (5), heated to in-
candmscence, is a sonrce oi electrons traveling toward the anode (1).
As a result of bombardment by the electron stream, the anode is
heated to white luminescence and a depression, the crater (3), at a
temperature of up to 40008k, is formed on it.
This is explained by the fact that the electrons traveling from
the cathode, impinging on the surface of the anode, give up their
kinetic energy and disintegrate the anode.
The luminous properties of an Eric are determined mainly by the
Fig.32 - Dia-
gram of Simple temperature of the crater. The crater radiates about
Arc:
1- Anode;
_.2- Cone of
anode; 3- Crater
4 - Flame arc;
5- Incandescent
cathode;
6 - CotSode
85% of the
luminous flux of the arc, the flame about 5%, and the cathode about
10%.1
The anode, or positive electrode, is 20-40 ms in diameter and
has an operuting temperature of about 4200'k. The cathode, or nega-
tive electrode, is 9-20 mm in diameter and has a temperature of about
3100'K. An arc lamp can operate oa either DC or AC. If as arc is
fed with CC, the positive carbon burns considerably faster than the negative carbon.
When an arc is fed by AC, the carbons burn dawn uniformly and tic crater is formed
in the anode, but the luminous flux obtained is smaller than with DC.
Table 24 gives the distribution of the luminous flux ia the electric
'
1
fed with DC and AC.
arc 4hes
The anode and cathode .af the simple arc are usually made of carboa or have
wicks enclosed in a hard shell of carbon. The wicks are made of & mixture of lamp-
4 t
f
)
fj
^
?
St
??????rr: ???Ggr.111 ?
P ? ? ........?..?????????????????????-,4 ?
;
?
black and waterglass. Electrodes with wicks burn more stably than carbon electrodes,
since the softer mass of the wick, evaporating lore stmney this the carbon shell.
Table 24
Cistrihntion of Lumizous Flax is an Electric Arc
Type of Current
Imainoes Flux in of Total Lartinons Flux
Positive
Electrode
'Crater)
1
EC 85 10 5
AC
47.5
47.5 5
Neqative
Electrode
Flame of Are
?4
form.v a gas cloud intensifying the ionization of the arc, thus facilitating ignitioa
and maintaining the stability of the burning conditions. The rate of bursting of the
carbons under normal conditions is 1 minis.
The siaple electric arc
cmllcd a desetadiag awracteristic - the
voltage between the electrodes decreases eivA
Table 25
increasing
current. To eliminate this
Eepeadesee ot Luminous Iatensity and Brigl.taess of ale Simple Arc
on the Cirrent Nalue (Bibl.9)
Intensity of
Current, Amp
420,
(Ls 9 as
4* VI aim.
d_ = 14 wet
de - 3e ma.
d_ z 20 air
I, ed 13. sb
I. a
E. alb
_
I, ed 1 II, ab
60
5,200
15.000
4,000
13.5%
-
-
eo
8,003
17,200
8,000.
-
-
100
11,000
19.000
11,00
14,500
8,30D
14.E00
120
14,500
20,500
-
-
12,0:0
15,0(0
140
-
-
16.003
17,C(0
14,800
15,4C0
160
-
-
-
-
16,200
15,600
180
-
?
22.500
M.00IO
20,01:0
15,700
200
-
-
-
.
22.500
ls.eco
1
phenomenon and stabilize the operation, as additional resistaace is connected is
7
s. ON. 4..
STAT
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?
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?
series with with the circuit of the arc, thus making the characteristic assume an as-
cending slope and causing the arc to burn stably. The additional (lellast) resistor
absorbs Irons 30 to 50% of the power of the arc.
The brightness of simple arcs
reaches 18,030-20,000 el with DC feed and 'about
12,000 sb with AC feed. The brightnese of the arc is only slightly dependent on the
length of the ere and the value of Lhe cur-
rent. With increasing current only the hei-
nous area and luminous intensity increase.
Table 25 gives data showing the dependence
of the luminous intensity (I) and the
brightness (13) of the simple arc on the
value of the current at varioqs diameters of
the positive carbon (d.) and of the negative
carbon (11..).
As will he seen from Table 25, in the
increases, the lumieneme intc=zity inczeasen
by a factor of about 3 times, while the brightness increases by a factor of less
than 1.5; in the second pair, the luminous intensity increases 5.5 times, and the
brightness about 1.7 times; in the third pair, the luminous intensity increases
2.7 times, but the brightness hardly increases at all. The luminous efficiency of
the arc is about 12-14 1m/watt at n current density of 15-17 amp/cm'.
The brightness temperature of the crater is Tb ' 38009s. and Che true tempera-
ture Tt 40001%.
At constant arc length, an increase in current from 8 to 60 amp, and AA Increase
in current density in the positive carbus from 30 to 210 amp/c', causes no change
in the brightness of the crater. In ordinary arcs, therefore, the current density
does not exceed 30 amp/cm2. The brightness of the siuple arc increases only with
increasing pressure, since the vaporization temperature of carton increases with is-
easing pressure.
The spectral distribution of radiation energy of simple arcs is shows in Fig.33.
0,7 44 as 009
a
1,0
F4.33 - Radiation Spectrum of
Simple Arc
a) %evelength,n; b) luminous
flux in relative units
first pair of carbons, when the current
s. ???????".???,??^T.
pt,
4
The radiation maxims is is the repos of 0.7-0.8 n. Thus the ordinary arc is a good
source of short-wave infrared rays.
Section 32. The high-Intensity Arc
The high-intensity arc difbtrs frns the simple arc hy an electrode arrangement
which allowe the current density to he increased, and consequeptly iaproves the il-
lumination characteristics of the arc.
The positive electrode of a high intensity are crosists of a hard compress-ed
shell and a wick. The nick diameter is usually 50-65% of the shell diameter. The
shell, as a rule, contains uineral additives, and consists of carbonblack, coke, or
graphite, and 1% boric acid.
A shell mainly coesisting of carbon black, is used at lom current densities,
while a graphite Shell is used at high current densities.
The wick of the positive electrode consists of a 33-601 eixture of rare-earth
fluorides (for instance fhorides of cerium, samarium, and lanthanum), mixed with
carbon black or graphite, with about 4% boric acid added.
The lusianns properties of "e arc depends on the composition of the shell and
the wick, and on the rethod of nanufactaring the wick.
licks for high-intensity arcs are either tamped or inserted. A tamped wick is
obtaieed hi compressing a liquid Tick mass into a pre-fired %lett. Is thin- case
liquid potassium silicate is used as a Linder. TO obtaia as inserted wick, the -sick
mass is passed through a round opening under pressure of some tees of atmoapheres.
Various powders can be used as binders is this case.
The negative electrode, like that is a sixple arc, has a wick. The carbons far
a high-intensity arc have a considerably greater Lrightaess and luminous ilteasity
Chaa the carbons for a simple arc. The Irightsess of the carbons of a siaplie arc
does not exceed 20.000 sh while Chat of the cartons is a high intensity arc say
reach 80,000 sb. The respective :animus values of the lariaous isteasity are
22,500 candles for a simple arc and 110,000 candles (almost 5 tines as greet) for
the high-iatensitv are.
77
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STAT
01.
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c.
a
Ilir,44.411.1Lagralarler4stt=.,-
Figure 34 schematically shows a high-intensity arc. As shown in the diagram,
the form of the flame and its direction are the same la in the simple arc, but a
bright gas cloud
from the cathode
depression of the
beginning at the -:rater is formed in front of the anode. The flame
forces this cloud toward the anode, concentrating the gases in the
crater. The brightness of the anode cloud is many tines as great
as that of the flare near the cathode.
The crater folmed in the positive elec-
trode, as a result of its vaporization at
high temperatures (about 500010 and as a
Fi g
the action
result of ionic Loebarginent, is filled
\
4.) with the vapor of the rare-earth metals
forming part of the composition of the
wick of the positive carboa. The nega-
tive ions formed near tht crater, under
Ciagrmm of High-Intensity Arc
a) Solid rick
of the electric field, form a negatively charged layer which determines
the boundaries of the flame near the anode.
The ponitive
ions recombine with "
electrons
-2 negative ions emitted by the
cathode; in this case energy is given off in the form of luminous flux. Thus, in
contrast to Che simple arc, in the high-intensity arc the pure thermal radiation of
the crater is supplemented by the luminescent radiation of the cloud of incandescent
vapor of the rare-earth elements contained in the positive electrode wick. Gains to
this fact, the high-intensity arc ia brighter than the simple arc.
The combustion products of the arc form a tongue of flame between the elec-
trodes, which, in the form of the so-called "beard' is projected in the beam of a
searchlight.
iligh-intennity arcs usually operate on DC, since their efficiency, when oper-
ated on AC, is lower.
The high-intensity arc has an ascending volt-ampere characteristic, shich makes
the use of an additional resistor unnecessary.
?
? ',sr.^^ .1/
?
_
_
The curve 1 of the spectral energy distribution of the high-intensity are, shows
?Fig.35, indicates that this arc has no narked advantages over the simple ere
(curve 3) as far as the distribution of radiated .energy in the infrared portion of
the spectrum is concerned.
This fact, as well as the necessity of using special devices for focusing and
rotating the
positive earl...A about the axis, and the necessity of cooling oysters,
- .
Fig.35 - Eadiation Spectra:
1- Of high-intensity arc; 2- Of a black body at I = 5OCW1
3- Of a simple are
a) 1avelength,;4 E) Eadiant flax in relative units
rake the design of this arc lamp considerably more complicated.
hiah-intensity arcs are used in ordisary long-lenge searchlights. Such arcs
are produced in special arc lamps whose design was first developed is 1874 by the
famous AUssian electrical engineer ii.N.Chikoleir.
The circuit of the arc lump is riven ?Fig.36. The electromagnet (5), con-
nected in series with the feed circuit of the electrodes, ensues instantaneous is-
Dation of the lamp. The electromagnet (I), connected in parallel with the feed
circuit, as the negative electrode turns away, automatically brings it closer to
the positive electrodes, thus regulating the distance between the electrodes, and,
consequently, the length of the arc. The electromagnet (6) serves to hold the
crater of the positive electrodes in the focal plane of the projector.
4
'
Ta lamps without automatic ignition, the negative electrode is brought lat.
contact 4ith the positive
electiode after whicb the electrodes are separated by the
necessary length of the arc. In lamps with automatic ignition, when the poet,
STAT
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Declassified in Part - Sanitized Copy Approved for Release ? 50-Yr 2014/03/27: CIA-RDP81-01043R002800190001-6
r.
?yr., ? ? ? ? ? to. ? ? ? %,woon..,
supply is turned on, the
?gt-l="411.71W
electrodes are brought into contact by a spring attached to
a lever connected to the armature of the
Fig.36 - Circuit Diagram of the Arc Lamp:
1- Anode; 2- Cathode; 3- Additional elec-
trode of red copper; 4- Resistors;
5, 6, 7- Electromagnet; 8. Motor actu-
ating arc leep
electromagnet (5). nen the power supply is
turned on, a current flows through the
winding of the electromagnet (5), and the
electromeguet attracut the armature, con-
nected over a lever with the shaft of a
lead screw ehich separates the carbons by
the distance neccssaty for arc formation.
The electromagnet (7) periodically brings
the carbons closer together, so that the
arc does not go out when they burn down.
Section 33. Tungsten Arc Point Lamps
The tungsten arc lamp, because of
the small size of the are diechnrge. is
called a point lamp. A charecteristic peculiarity of lamps of this type is
high over-all brightness. Figure 37 gives
Fig. 37 - Layout of Tungsten Arc Lamp
their
an external view of the tungsten lamp.
fig.38 - Layout of Point Arc Lamp with
Conical Incandescent Body
The arc discharge originates at the instant of separation of the two tungsten
?
tsr VIP
?
_
electrodes, having the form of a sphere and hemisphere of a diameter of 1-6 mm, de-
pending on the power of the lamp. The bulb of the lamp is filled with nitrogen or a
mixture of hel;um and neon. then the voltage is turned
off, the electrodes are in contact; at the instant the
current is supplied, a high current passes through a
bimetal plate. The plate. heated by the current, bends
and separates the electrodes by the required distance.
The brightness of point lamps of 1 kw powet is
t.
) I
- Layout of Com-
bination Lamp:
1- Tungsten spiral;
2- Mercury lamp;
3- Bulb
2500 al), at a luminous intensity of
The lamps may be fed IT CC or AC.
Tungsten arc lamps with an incandescent body in the
fora of a sphere have proved to be inconvenieat in oper-
ation, and this led to the necessity of developing an
improved design of the tube with a conical incandescent
body (Bib1.10).
Dith an incandesceut body of such form, its pro-
jection is completely filled by the luminous filaments.
The brightness of such a lamp, of 100 watts power
and 12 ? voltage, is eqaal to 1100-1510 sb, while the area of the projection on a
plane perpendicular to the axis of the cone is only 0.11-0.158 am2. The life of the
lamp is about 270 hours. The lamns can be made for various voltages from 5'to
up to 4000 candles.
?
40 volts, and in sizes of 30 to 3000 watts. The incandescent dy is placed along,
or perpendicular to, the axis of the bulb.
The principal advantages of this design of the poiat lamp are: its -relatively
great brightness, its use of either CC or AC, aud the possibility of directly cos-
necting it to the voltage source without a connection circuit.
Figure 38 schematically shows an external view of the Point lamp with a comical
incandescent body.
The combination lamp developed by the Moscow electric lamp pleat is a goal
source of near infrared rays (Bib1.10a). The desiim of such a lamp is schematically
shows is Fig.39. It consists of a cosbinatioa, in a single lull), of an extreme-
I ? *bs4SM.,, LA...
. .
L.
81
STAT
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'pressure
The
?
???????
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a a
low-power mercury lamp and a tungstes incandescent lamp.
tungaten spiral (1), which is the principal source of radiation
*4
t s
r (0,
"jJ
,1
; ?
t I I
:i ?
. ? I -?
I ? e? ? ?
? , i
1
4 'ill .....?..,.: ,z. ? . -;.......... I
I .._. _ ?
-.. ?
l.. , .3. ' 1 1-r ,
-
IA. A li i i i / 1 1 i i\:A i
it , ; i , ! : ' t i
I II 1 ? F--; -11 '..! Fi-rA
1
0.1-1____!....._ f.
. , , I .4_,ii.; 1
i
.., --,--- i`ji 11 iiIIIIIIL 1
...
1 I
doq,) 445 0,5 a6 47 5,Zag 7 .,2 ',4 0 0
Fig. 40 - Spectrum of Combination Lamp
a) *avelength,4; b) Intensity of radiation in relative
units
infrared region, is cr.nnsfeteti in c.oris.s with the =ercur.i.lap
?
- ballast resistor.
Figure 40 gives
p
Vlt --J
in the
ser,Tes aa a
the curve of spectral energy distrilution of the radiation of
the combination lump. As indicated by this cur-ye, the
lamp has a continuous spectrum in the near infrared re-
gion, with individual maxima of high intensity.
Fig. 41 - Schematic Diagram
of Mass Radiator
ate explained in Fig.411.
The glass vessel A is
Section 34. The Mass Radiator
In 1923, Professor A.A.Glagoleva-Arkad'yeve pro-
poted a new and original source of infrared rays called
the mass radiator. The mass radiator consists of a
source radiating in the intermediate region
trum lying between the shortest radio waves
infrared rays. Its design and principle of
of the spec.-
and the long
operation
filled with the so-called vibrational mass $1, consisting
???*'......??????-???"??????? ???-? 41. ?????????.?*11J1??????,,? ..?.??????-????????sOrm...,*?..?-.1. ?0*?-????4,a 4.???????????/,..?
? . ?
I.
;
-7 ?
?
.43
a
of a mixture of metal filings and machine oil.
The continuously rotating mixer P maintains uniformity of the mass. ,ithia this
MIMS, a small cart-elite
sheel (E) rotates and entrainu the mass, causing a viscous
coating (P) of metal filings tin form on
the surface of the wheel.
Py means of the conductor-di:charges
(P), a high voltage is applied to the sur-
Lace of the wheel across an inductor. The
dischargcs between the conductors pro-
duce electric oscillations whose period
is deterzieed primarily by the size of
the filings. Figure 42 gises the curve
of the radiation spectrum of the
70
b)!,
o as
2x xv
a)
Fig.42 Radiation Spectrum of Wass
Padiator
a) lavelength,; II Intensity of
radiation, %
Glagoleva-Arkad'yeva mass radiator.
Section 35. Extreme-Pressure Krypton-Xenon Lasp,
Extreme-pressure 250- and 750-watt krypton-xenon
lamps are of interest as ra-
diators in the region of the near infrared. The 750-watt lamp is designed is the
fora of a quartz tube 36 631: is diameter with two verticall7 arranged tangstea elec-
trodes. The upper electrode, which is the cathode, is coated with an oxide layer.
The ignition of the discharge of the lamp is effected Lw Beans of a third electrode,
-of tungsten wire, placed perpendicular to rhe cothode and anode. The lamp is filled
with a mixture of krypton and xenon under 15-30 eta pressare.
In the near iafrared region, the lamp radiates a continuous spectrum, approach-
ing the radiation of ? black body at a temperature of 5200-57009. with iadividaal
intensity lines in the regions 0.76; 0.82; 0.84; 0.9 and 1 p. Sith increasing
atomic weight of the gas, the radiatioa mania= shifts toward the long-wave portioa.
A pulsatiig discharge is one of the forms of non-stationary gas discharge, re-
seekling a e;srk discharge. Whea high-capacitance high-voltage capacitors are dis-
charged into a ges-discharge tube, an exceptionally great brightness, as high as
83
? ? ????,... ? ,...??,?? "???......? ...31.*Art-lig,1?214??????{6???:**41.7.6 sata-f?? 1 ? * c?.? :4. ?
? .
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STAT
STAT
Declassified in Part - Sanitized Copy Approved for Release ? 50-Yr 2014/03/27: CIA-RDP81-01043R002800190001-6
I
L. ??????????..
???????,..
...? ? ...6 ,....????????????,. 6r ?1 ...,,19.,?)?????,,, ......., , ... r,???? ????r ? ? ....V.,. ?, ? ..11, .... s ???? ????????r. ....-,,, ? ...,,... ... ..?
.......--,1)?-? 6 .......e?-?
i
? 1
..a
arra
I I
* i CI . I ? ?
1111 ..?
0
I
1
???
C? V
0
C) 6.11
40,
11
9.1 ????????
0 V e?
C? PI el
1.1
WI
0 0 ii
.4 ,C
?-?
3
3
I ?
8 a 3 ? ? 3 8 8
61 6* *)
3 8
ir.? 4 v cti
r.? CI ra
????
UP al
? ?
ei
. .
I-
?11
e
??? ?
WI
A
3
8 8 8
a o
3 a a
ro
?-? ?.?
.00 WIg
0 IP-
?-?
WI
VI
0 Ws PS PS
. Via . ? ? ?
left. 61 ??? ??? v.
?
???
15.000-11.000
V VI
545 i WI
Ca
?.?
0 CP V
44
WI a CI"
V 0
^ g CI71 Cl
3
? MI 0
??? 4.? 0%
??
I.
le
?
?
I.
I. is
a
A
a VI III
A A .4 P ...I.'.
9.? 11. 8 8 8 1 -?
? ?
4t 4e4-6 U
.6
?
? i >Cti ? 8
. ..... ??? ? y
L .44 21 X Z X X
I 9 ..9 1/??
O 49.9
a?
1 (9 ???
???? ?
I.
.4 4 a
1 ..
V1)34-250
???
SVD.-1000
'direct current
aluirmaime curromt
0
"?":"."'"
_
6
.6?? "ro?????????,r, COI...
????
SI
CS
8
WI
a
o
a 8 3
.-.0
8 0 ?
.4.
0. 3? .,.... o
....1 Cl vs 07 Cl 2
tia 4. CI
CI V 0 i i
01 C ??
,....:
C ; a
???
a
?
?
???
? I ? S ? ?
? ? ?
a
?
?
0 V
0
Cl2 A
? ? 10 ? ? ?
V S. 0 V
11.? 0
???
0 a a
3
..
?-?
a ?-?
? . ? ? ? ?
?fl IV V 60.
61 V 3 a a
0000
.1? 12 WI 01 ... 4,
.1 0
0
A
4 . ?
CI 0 ?
V ?
a ?A 2
? .- ri
A r? ea Cl in ....
a
dirmet cm rrrrr
thagaWa paint
3
Smorcilblight are lamps:
kelgis?imuomal Cy
,
?
t
????
???? ? ....A.-. 1
2
*
a
Current in operating
I????
a) Noma and type of lamp; 14 Power conaumed, watt.; ci Volta,* in operating Atilt0.11;
85
Luainoua flux, lw;
atoms, amp; a)
Life, hours.
?
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?
4..4 rINV?fa..1/1MM,0*^Vr.efir re- l'Af.,4????1:- p.c.'s?, kw', I.,
Declassified in Part - Sanitized Copy Approved for Release ? 50-Yr 2014/03/27: CIA-RDP81-01043R002800190001-6
.4.????,?????????
?
60 X 104 sb, may be obtai.led, with the flash of the lamp Persistent about lo'S-sec.
Ge of the types of pulse lemps developed resembles the extreme-prestnre krypton-
xenon lamp. The difference is only in the interelectrode distance and the bulb di-
ameter. A lamp of another type is made in the form of a tube of refractory glass or
quarts, with an inside diameter of 1.5 to 10 mm. The ends of the tube are provided
with cylindrical nickel electrodes, sometimes coated with a layer of barium or cesi-
um. The distanee between the electrodes, according to the voltage, may be as great
as 1.5 m in high-power lamps.
Pulse lamps are usually charged with 90% krypton and 10% xenon, but the lamp%
? may also be filled with helium and sei,n, thus shifting the radiation spect m toward
? the longer wave portion.
In concluding this Chapter, we present a Table of the principal data of gas-
_
discharge lamps (cf.Table 26).
,
n
CHAPTER%
PHOTOELECTRIC CELLS MTh EXTRINSIC PHOTOELECTRIC EFFECT
Section 36. Principal Types of Hadiant-Eaergy Indicators
The conversion of radiant energy into other forma of energy (electrical, mechan-
ical, chemienl, or thermal) is accomplished in various ways. The instruments and
devices servinz to convert radiant energy and to record its conversion into some
other form are called receptors or indicators of radiant energy.
Indicators that directly transform radiant energy into electric energy, using
Coe photoelectric effect, are called photoelectronic indicators. This group of in-
dicators includes photocells, photoelectric cathoden of electron-optical transducers,
and electron aultipliers.
Other indicators of radiant energy are thermocouples. bolometers, optico
acoustic and pneumatic indicators, which transform the energy into heat, thus heat-
ing a sensitive element.
The conversion of radiant energy into chemical energy is detected by photo-
-. _graphic plates and luminous compositions, or luminophores.
Indicators of radiant energy are divided into selective and nonselective. As
indicator is called selective if its sensitivity depends on the wavelength of the
- incident radiant flux. This group includes all photoelectric, chemical, and lumi-
nescent indicators. Nonselective indicators have a constant sensitivity in a defi-
nite, relatively wide region of the spectrum of infrared rays. Representatives of
the group of nonselective indicators are, for instance, thermocouples and bolometers.
The technical types of photocells, in existence at present, use three forms of
the photoelectric effect, extrinsic, intrinsic, and in the blocking layer.
norlaccifiincl in Part - Sanitized Coov Approved for Release
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4
Section 37. The Concept of the Extrinsic Motoelectric Effect
- 117. mr-erftirlarIllarelltIMS?111M?As.a
The emission of electrons by substances under the action of radiant energy flux
incident on its surface is called the extrinsic photoelectric effect. Absorption of
this additional energy causes the electrons to fly off the surface of the substance.
The simplest device for producing the extrinsic photoeffect
plate (e.g., silver) negatively charged (photoelectric cathode),
If a galvanometer is connected in the circuit, a current Appears
consists of a metal
and a metal anode.
in the circuit %hen
the cathode is illuminated, causcd by the electrons escaping from the surface of the
photocathode and impinging GA the :node.
Eetailed studies of the extrinsic photoeffect were first conducted in 1808 by
the prominent Russian physicist A.G.Stoletov, Professor at Moscow University, who
termed this phenomenon the actino-electric effect. He made a valuable contribution
to the study of the extrinsic photoeffect mu has the distinction of having dis-
covered the fundamental laws in this field.
Stoletor discovered the fundeEental law of the extrinsic photoeffect namely,
that the photocurrent is directly proportional to the radiant flux falling GA the
photocell. He also established the unipolarity and absence of inertia of the ex-
trinsic photoeffect, as well as the dependence of the photocurrent on the applied
voltage And the nlectrode spacing.
?
He established that, at a given pressure of the gas, the photocurrent has its
maximum. This phenomenon of resonance of the photocurrent was denoted as "Stoletov
effect".
The results of Stoletwes numerous studies of the exttinsic photoeffect formed
the basis for all further research in this field.
In. 1899 the electrtlic nature of the photoelectric current was demonstrated,
and in 1899-1900 it was established that the electrons escaping from the illuminated
surface of a me:al possess energies of a feu electron-volts, and that this energy de-
pends on the frequency of the incident radiant flux, rather than on its intensity.
The great Soviet physicist, Acedeaiciaa A.F.Ioffe, made valuable studies on the
11
________
e
mowte of the photoelectric current. P.I.Lakirskiy and S.S.Priltehayev, who first
developed the classical method of quantitative verification of the fundamental equa-
tions of the photoeffect, rendered great services in the study of the extrinsic pho-
toeffect, as have I.Ye.Tamm, P.%.11mofeyev, N.S.KhleLnikov, and other Soviet '-
physicists.
Section 38. Structure of Solids
The photoelectric procesaies can be completely explained from Che point of view
of the quantum theory. For this reason we give below the principles of the eweacum
theory of the structure of solids, necessary for understanding the basic nature of
photoelectric phenomena.
All solids are divided into three groups, according to their photoelectric
pioperties:
ketals, with high electrical conductivity;
Smeiconductats, with lower conductivities than metals;
Insulators (dielectrics) whose conductivity is close to mere.
All solids consist of &toes or molecules.
In a metal, the outer electrons of the atom, which are farthest from the an-
--clefts, are weakly bound to the met:1=a are able to move freely within the metal.
- from one atom to another. These electrons are called free and are responsible for
: -
_the conductivity of the metal.
The electrons bound to the nucleus (clesee to the nucleus) cannot leave the
ft
. atm. These electrons have no influence oil the conductivity of the metal, since
they cannot be displaced, even under tle actiom uf a powerful external electric
- field.
According v. the quantum theory, confirmed by experiment, the electrons of as
atom can exist only in a definite discrete set of stable states. The transition
hum
_ one stable state to another can take place only by a jump. At the instant of
such
a trassitioe, the atoms radiate or absorb energy of -:trict17 e.stemiaate ire.
queacy.
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The electrons in the atom pave at various distances from the nucleus and pa-seas
various snergy levels (beginning uith the level of minimuw energy), various values of
the energy, and of the force of attraction to the nucleus. Each electron is ia a
'state, and possesses an energy, not inherent to any other electron of the particular
atom.
The energy levels form what are called sets of allowed energy levels, and only
in them can electrons be found. The intermediate regions betmeen the zones, In which
1
A)
I)
???????1.1.
17.17.a.7.7171
Fig. 43 - Schematic Diagram of Energy Levels of Electrons:
a) In metnis; h) In semiconductors; c) In insulators;
d) Energy; e) Free allowed level; f) Lower allowed level;
PO Nucleus; h) Free zone; i) Forbidden zone; j) Lower
filled zone; k) Nucleus; 1) Upper free zone; m) Forbidden
zone; n) Lower filled zone; o) Nucleus
- there can be no electrons, according to the quantum theory, are called forbidden
zones:
The properties of solids are primarily determined by the energy levels of their
electrons.
The enczgy levels of electrons (Fig. 43) are usually presented graphically in
the form of a series of horizontal lines. The energy is plotted along the vertical.
As will be seen from ig.43 a, the lever forbidden zone of energy levels
1.
metals is filled with electrons. Above this is a free zone of allowed energy
is
levels.
The free (external) electrons may pass from a low energy level to a higher one in
the free zone, thus causing conductivity of metals.
C, . _
The schematic disgrop for semiconductors (Fig.43 b) shows that the lower energy
levels are likewise filled with elect,-^ns, bat, in contrast to the situation in a
metsl, the free zone is separated from the lower region of forbidden energy levels.
The width of the forbidden zone varies in different semiconductors. To sake the
transition from the lower filled zone to the upper free zone of allowed levels, the
electron must overcome a potential bairier, determined by the width of the forbidden
zone. le overcome this barrier, additional energy murt be imparted to en electron.
The quantity of energy necessary for em electron to overcome the barrier and to pass
into the upper free zone, determines the degree of conductivity of a semiconductor.
In insulators (Fig.43 c), the lower filled zone and the upper free zone cre
:?
separated ty so vide a forbidden zone that a transition of electrons in made in-
_
--possible, even with a considerable additional energy. For this reason, the conduc-
tivity of insulators is practically equal to zero.
lhos the quantum theory successfully explains the phenomenon of conductivity in
nelida. Aa already pointed out, the transition of electrcns from one level to as-
_
other is accompanied by radiation (or absorption) of energy, i.e., by the phenomenon
t ' - of the photoelectric effect, or luminescmnce.
_Section 39. Fundamental Laws of the Extrinsic Pbotoeffect
. --Proportionality of the Photocurrent to the Nalue of the Incident PMdiant Flux
The first lav of the external photoeffect, discovered by A.G.Stoletov, es- ,
....__tablishes that a direct relation exists between the number of photoelectrons N es-
coping from the surface of a metal and the radiant flux Di incident on it:
N ? kit (102)
The photocurrent iph arising in the photocell between the cathode amA the
anode, is ditectly proportional to the incident radiant flux it
irk ? a. (103)
The proportionality factor a serves as a measure for the sensitivity of the
photocell surface and is determined as the integral sensitivity of the photocell.
?????????
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77.17:or)>.' *-"ist -et, ?ta.r. rcr ,?Eir".."1-'4"1:1"--V"r ?.*,'""t
0_, _
Fundamental Equation of Energy (irst CUantum Belation)
According to the quantum theory of light, a radiant flux consists of discrete
particles, or quanta, possessing a definite energy. The energy of a quantum of ra-
diant flux, or photen, falling on the surface of a metal, is absorbed by one of the
electrons on Che energy level. If the electron has received enfficient energy frem
the photon, it is able to overcome the potential barrier at the boundary of the metal
and escapes into the surrounding medium. The escapinx photoelectrons have different
velocities, since, having been at different energy levels and, consequently, at dif-
ferent distances from the surface of the metal, the', traverse = different thickness
of that metal and lose different quantities of energy when they strike a molecule.
Let U be the minimum positive energy at which, prior to iiradiatioft, not a
single electron can leave the surface of the metal. If, under Che action of the ra-
diant flux, an electron with a charge of e leaves the oci.ol and impinges on some sur-
face with zero potential (for example, on a grounded plate), then the work performed
by it will be equal to lie. If at the moment of leaving the surface, the photo-
- electron had the energy V, then the residual energy of the photoelectron on the oar-
- lace of zero potential will be equal to
At% lie, a photoelectron will arrive at the surface of zero potential after
it has expended all its initial energy of flight Ile, which is converted into kiaetic
_
2
energy of motion, equal to 2. Thus, in this caae, all the potential energy allow-
ing an electron to escape from the natal, will be equal to its kinetic energy of mo-
tion. i.e..
Mr
2
a Ue (104)
where a and m charge and mass of the photoelectron, respectively;
v velocity of the photoelectron.
Hance,
ij
(Th
a M.
T
(105)
A measurement of the velocities of photoelectrons *inkier different conditioaa
alloyed ohe of the fundnnental laws cf the photoeffect to be established: the veloci-
ties of photoelectrons escaping from a metal do not depend on Che incident radiant
flux but only on its frequency.
The relation betseen the velocity of the photoelectrons v and the frequear-y of
the incident flux of radiant energy, v was deterained on the basis of the quanta's
theory. then an atom absorbs the energy of a photon by (where h is the Planck -con-
stant), then the liberated photoelectron gust expend part of its energy to overcome
- the potential barrier at the boundary of the metal, is order to detach itself from
that surface. This energy is called the work function of the photoelectron vo and
- is expressed in eltctron-rolts. Another part of the energy, hoverer, is converted
2
tat
into the kiaatic of this ph 2
otoelectron =
According to the law of conservation of energy
^
?
Or
2
hv ? e9,
(106)
Ut a hv ? ego (107)
Equation (106) my be written in the form
2 1
2
a
Equation (103) is the fundauestal equation of the extrinsic photoeffect and is
sommdmes called the first quantum relatima.
If all the energy of the absorbed photon is expended in overcoming the potential
IT,rrier, and tha velocity of the escapiag photoelectrons is equal to zero, them
93 -
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Declassified in Part - Sanitized Copy Approved for Release ? 50-Yr 2014/03/27: CIA-RDP81-01043R002800190001-6
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- -------;-? -
ir."0.1..)."41.- 'An., .#7.1 PtiNit
. ?-?-te-viirse ,
where vo is the limiting frequency at which the electrons will leave the surface of
the metal at zero velocity.
TO the frequency vo corresponds the wavelength X0, which is called .he long-
wave, or red, boundary of the photoeffect. The term "red boundary is explained by
the fact that, at longer wavelengths (in the direction of the red portion of tbe
spectrum), no photoelcctronic emission takes place.
From eq.(109) we obtain
by. he 1
? ?
? ke
where c = speed of light;
Xo = long-wave (red) boundary of photoeffect.
Hence
? he 1216
k ?
it ? ? re
??
(1.10)
It follows from eq.(111) that, at decreasing work function, the long-wave
boundary shifts toward the red and infrared portions of the spectrum. At decreasing
wavelength, the energy of the photon hv increases, and, consequently, so does the
yield of photoelectrons (photoelectric emission), bet caly up to a certain limit,
- after which the emission drops off again. This iL explained by the fact that, at
increasing frequency v, the number of photons of the radiant flux with as euargy
,T equal to 1go-decreases and, consequently, the photocurrent also decreases. TO reduce
the work function, the absorption may be increased by depositing a monomolecular
--layer of atoms of an electropositive metal on the surface of the principal metal. Is
- this case, between the principal metal and the surface layei of adsorbed atoms as
intermeaate layer is formed, usually iu the form of an oxide of the principal betel.
- By varying the absorption, a different work function may be obtained so that the
Long-wave Scoudary may be modified. At small values of the coefficient of adsorp-
tion, which are characteristic of a pure metal, there exists the to-called normal
photoeffect, in which the sensitivity increases exclusively with decreasing ware-
?
C
_ ._ _ _
length. At increasing coefficient of absorption, the selective photoeffect takes
place: the photocurrent has a maximum is the spectral land of absorption of light by
the adsorbed atoms of the electropositive metal.
The value and positiou of the selective simians depends on the thickness of the
intermediate layer and of the layer of electropositive metal, as well as on the
valence of the metal.
The wavelength of the selective &exists& may be determined by the empirical
formula
2ne
2
I air
(112)
vbere r ? radius of electron, n = mass of electroa.
The calculation results obtained from eq.(112) differ little from the experi-
mental data.
Tle Qui...lama Equivalent
- The ouster of electrons per unit of absorbed radiant energy increases hr the law
i
i
of the quantum equivalent (the second quantum relation), according to which c.te ab-
_ - sorbed photon of radiant energy must liberate one phottelectrom.
_ 4
. _ Assume that, is liberating N photoelectrons, forming a photocurrent, the re, ;
_
. chant energy It. with a frequency of v, incident oa the surface of the photoelectrii-
--cathode, is absorbed.
i
Thea the nosier of phctoelectroms leaving the cathode on absorption of this en-
ergy will be ecool te 11
1
N *
ha
(113)
where h s Plaack's coastaat.
If each of the N absorbed photons literates one photoelectron. the*
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greater
N!--- = -
kv
, ... .?:?; ?!.? *IV. lir Irftroallt INIMMIIMMIT'artr...r1.11
(114) -
follows from eq.(114) that the number of photoelectrons liberated cannot be
111
than?
table 27
Enemy of Photons (Quanta) and Puantun Equivalent
lavelength,
g .
Energy of Photons
(11antua Equivalent
ergs
volts
Number of
eleetrons/erg
sa/watt
0.6
3.31 x 1042
2.06
3.02 x 1011
484
0.75
2.65 x 1042
1.65
3.78 -L 1011
GOS
1.0
1.99 lc 10-12
1.24
5.04x 1011
807
1.5
1.32 x 10-12
0.83
7.56 x 1011
1210
2.0
0.99 x 1042
0.62
10.08 x /011
1614
If only a part n of the absorbed photons liberate photoelectrons, the,
N
The photocurrent per unit energy absorbed is determined by the relation
*x eh x
71_ . _ n ? _
hr d he e
--where d = electrode spacing of the photocell;
(115)
(116)
x = distance traveled by the photoelectrons.
Table 27 gives the values of the energy of photons (quanta) and of the quantum
- equivalent, for a few wavelengths.
The law of Cie quantum equivalent, in the general form characterises the in-
- tensity of the photoeffect.
On the basis of the law of the quantum equivalent, the quantum yield may be
calculated if the spectral sensitivity of the photocell in absolute units is known.
?
4 - . Pw....10.? a. a. wow,. or 044,114i1r.-4,4??? 14,4 ?
r
Section 40. Lon-leve Boundary and Rork Function
If the wavelength of a luminous flux incident on the surface of a photoelectric
cathode is beyond the limits of the long-wave (red) boundary, thra the energy of Che
--light quanta becomes insufficient to enable the photoelectrons to leave the surface
of the metal. This value of the energy determines the threshold of the photoeffect.
The work function for various metals is different. It depends on the position
of the metal in the periodic system of the elements. The electron theory of attain
'permits an approximate -letermination of the la' goveraimg the work function go in
pure metals on the basis of the quantative relation letween the atomic weight the
atomic number of the element Z, and the densi4y of the substance E4
ZU
9. C (-i---)
(117)
where C factor of proporticor.lity.
Table 28 elves the lone-save boupdariea and values of the work function of the
electrons for the most important pure metals.
The alkali and alkaline etrth metals, particularly cesium, have the smallest
- work functions while combinations of cesium with cesium oxide have the smallest work
--- function of all, amonetiug to about 1.0-0.7 v. This is the reason shy a cesium sur-
_
? -face is selected as the surface layer of photocathodes sensitive to both visible and
'---iavrared rays. Photocathodes of this type are used is so-called cesium photocells.
Sectios el. The Contact Potential Differeso_
If two grounded surfaces having a different work function are placed in a vacu-
um and a radiant flux is directed onto them, then the photoelectrons emitted hy the
surface with the :nailer work function will be concentrated on the surface with the
higher work function.
As a result, the latter surface will be negatively charged with respect Is the
former, and an electric field sill form is the photocell between the anode and
010.4.4.it".02'rtow.10e2.4?46461?00144:441.4.
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?
1414,????.. 4????1?o? re??????????4444?414.44414.,... P. 4 go..iptrlaori...1.0..w.er.e4 ....I. or 44,.;4444???,
cathode, possessing different work functions. The pot;.tiiei-tillierence,--fOr-SiTadin--
this case on the surfaces, is called the contact potential difference and is equal
Table 28 '
Long-ave Boundaries and Work Functions of Electrons of Pure Metal%
Metal
A.
wo
% 1
volts
Metal
X* 1
I
9*
volts
?
Lithium
510-540
2.42-2.28
Thorium
336-370
3.68-3.34
Sodium
583-600
2.11-2.05
Gereanium
255
4.85
Potassium
612-710
2.01-1.74
Tim
281-350
4.31-3.52
Pubidium
810
1.52
Lead
298-355
4.14-3.48
Cesium
630-900
1.96-1.87
%medium
326
3.78
Cepper
266-303
4.63-4.07
Taots.lue
297-315
4.15-4.92
Silver
258-268
4.78-4.61
Araenic
236
5.23
Gold
252-260
4.9 -4.74
Antimony
307
4.02
Beryllium
374-39?)
3.17-3.3
Bismnth
278-3?0
4.44-3.74
Magiesitin
330-450
3.74-2.74
Chromium
330
3.74
Calcium
385-510
3.2 -2.42
Nblltdenum
258-297
4.33-4.15
Strontium
550
2.24
Tungsten
230-273
5.26-4.52
Barium
540-650
2.28-1.9
Selenium
220-267
4.62-S.61
Zinc
302-346
4.08-3.57
Manganese
321
3.76
Cadmium
305-330
4.05-3.75
Radium
248
4.97
Mercury
260-273
4.75-4.52
Iron
259-31.5
4.77-3.92
Alumintma
298-439
4.14-2.81
Cobalt
290-315
4.25-3.92
Gallium
291-300
4.2 -4.12
Nickel
246-336
5.01-3.68
Thallium
335-360
3.68-3.43
Rhodium
251
4.92
Titanium
313
3.95
Palladium
249-2C0
4.97-4.31
Zirconium
322-330
3.54-3.73
Platinum
185-280
6.67-4.4
?
to the difference between the vork functions taken with reverse sign:
Up. g
The maximum potential entering into eq.(107) is equal to the negative *no&
potential only where the work functions of the anode and cathode are equal. If.
however, they are not equal, then the quantity elUp.4 is added.
The measured maximum potential is thus
?
hv.
- ?
p .d
?
hv
? 95 + ge 4 ? 9/1
?
1 r . _ -- .. _ ... _
This equation shows that the quantity U; depends on the frequency v and the
work function of the epode 9A, but does not depend on the work function of the.
1 cathode 9c.
I
1 Section 42. The iota! Photoelectric Emission
1 0 If 2 radiant flux emitted II a body at a temperature I strikes the surface of a
^
photocathode, the total photoelectric emission can be determined from the equations
by.
?
)10,14e IT
tf
x A Tile II
Ph Ph
where Aph constant of photoelectronic mission;
K ? Eoltuman constant, equal to 1.372 x 1016 erg-deg;
d . an exponent (about 2);
t
the charge of the electrons;
e the base of naturs1 logarithns, equal to 2.718282.
hlf CO
Lenoting by the letter 1, we obtain the formula
i A T4e
0
(la))
(121)
(122)
From this formids, the Pork function of photoelectronic emission cam be de-
termined if the value of the emission current has been measured.
Section 43. The Extrinsic Photoeffect inecreeloxPhotocatIodes
- A metal plate or layer of pure metal on a glass base, with the surface of the
;
'metal oxidized and a layer of adsorbed atoms of an electrically positive wetal on
- that surface, is called acookokdrphotocadode.
(119) Is their electrical properties, coated photocatodes belong to the gromp of
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semiconductors, since they have a negative temperature coefficient of resistance
(i.e., their resistance decreases with increasing temperature).
The electrons of the lower filled zone (cf.Fig.43,1) play tht principal role is
the formation of photoelectrons (photoaectronic emission). This follows from the
fact that photoelectrons are formed when an electron alsorls the energy of a photon
of a radiant flux, and therefore tLe maxim effect shealt: bo given by a zone where
the greatest number of electrons is aoncentreted, i.e., the lower electron-filled
zone.
In addition, the atoms of an alkali metal adsorbed on the surface of the photo-
-cathode participate in the formation of the photeelectronic emission.
In emissive photocells designed for operating in the infrared region of the
spectrum, coeted oxygen-cesium photocathodes are used, which consist mainly of three
. - components: a metal base (substratum) of silver, an intermediate layer of cesium
- oxide, and a thin layer of atoms of the alkali metal cesium.
- Such photocathodes, with the chemical formula OLIO Cs or, tr;1h s eqeker
_ intermediate layer, [Ag) - Cap --Cs, have a long-wave boundary between 0.8 and 1.1u
and a maximum sensitivity around 0.62 P. i.e., they possess sensitivity to the short-
wave portion of the infrared spectrum.
At present, more sensitive ox3gen-cesium cathodes are being built, in which the
-intermediate layer consists of cesium oxide (Cs20) with atoms of cesium and silver
/
- disseminated in it. The structure cf such photocathodes may be represented by the
t __- formulas (AO - Ca20, Cs - CS and [AO - Cap, Cs, Ag - Cs.
Table 29 givea the values of the long-wave boundary A0 and the spectral mill-
i
--mum 'wax for different oxygen-cesium photocathodes.
The possibility of constructing photocathodes from alloys must be pointed cat.
It has been found that photocathodes of high photoelectric sensitivity can he made
from alloys of cesium with a metal of very low conductivity (for instance, Sb,
Pb, Ti). Such photocathodes have a peculiar property: The metal of the base ham Ao
influence on their spectral sensitivity and modifies only the integra sensitivity.
rl,,...??????Sr? ????? worra srsss.efirrs,sssar.,,,..,
rWISs,???????? ????? ????drrrr rssr?s. ,dsssrsrss.r.s. -
Section 44. Ives of Emissive Photocells -
Depending en the filling of the tube and the design of the electrodes; emissive
photocells can he divided into several grcops. According to the filling of the trim,
Tsble 29
Long-save Boundary sad Spectral Maximsm of Coated
Oxygen-Cesium rnotocathodes
Cathode
A.
ii
Xmas
a
?,
0.8
0.35
No - Ca20 - Cs
0.9- 1.1
0.62
r?Agl-Cs20, Cs-Cs
1.1-1.2
0.7 - 0.8
c.A4 -Cs20, Cs, h- Cs
1.2- 1.3
0.75-0.85
? - they may Le divided'into two groups: vacuum and gas-filled. In the tube of photo-
ceils ot the tomer group, a high gamins of i0-3 an Mg is created. The tubes of
0 photocells of the second group are uned with an inert gas.
In the design and arrangements of the electrodes, both groups are divided into
photocells with a central anode, with a central cathode, with parallel or with sym-
metric electrodes.
Of all emissive pLotocelis, only those with coated oxygen-cesium photocathode
!.."
are indicators of infrared rays. Se will. therefore, consider only these cells in
:the followiag.
. Section 45. Principal Characteristics of Emissive Photocells
Emissive photocells have the following principal characteristics:
Integral sensitivity, representing the ratio of the photoelectric. current in
- the circuit of the photocell to the power of the radiant energy incident on the
- -
photocathode, at a definite radiator temperatare. 4Iu
. amperes .
Integral sensitivity is expressed in - (smn/w).
watts
-f.
the epectrum, integral eeamitirity is usually expressed is
101
For the visible part of
microamperes
Imams
(0 asp/10.
STAT
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. - rt* -lretr.grtilrlarargeMall.fr
trer?rx vra...-.%mtiNgw..apetz*.# aosp evzo.N....ZreA." t.ss
v.
Spectral sensitivity, determining the dependence of integral sensitivitv, ex-
pressed in absolute or relative units, on the wareleneth (frequency) of the incident
radiatinn. The graph of spectral sensitivity is called the spectral characteristic
of the photocathode.
Luminous characteristic, showing the dependence of the photocurrent on the is.
cident rudiant (luminous) flux at constant applied voltage.
Volt-ampere characteristic, showing the dependence of the photocurrent on the
applied voltage.
Dynamic (or frequency) characteristic, determining the dependence of the vari-
ation in photocurrent or in sensitivity on the aodulation frequency of the incident
radiant flux.
Sluggishness or inertia, characterizing the time after which the photocurrent
_
? - reaches its maximum value, measured from the beginning of irradiation of Lite photo-
- cathode surface by a constant radiant flux.
? _
Threshold sensitivity, or energetic threshold, determining_the minimum value of
the power radiated in watts, which can be registered by the photocell.
--Section 46. The Integral Sensitivity of Photocells
The integral sensitivity is due to the distribution of eaergy in the spectrum
--of the radiation source, since a radiant flux from sources at different temperatures
?produces a photocurreet of different value.
3,--
- QUuntitatively, the integral sensitivity is expressed us the area bounded by
the curve obtained on multiplying the values of the spectral sensitivity of a photo-
cell by the value of the energy for the spectrum of the radiation source.
In this way, to determine the integral sensitivity of a photocell wises ir-
radiat..i by a source of non-monochromatic radiation, it is necessary to construct
the spectral sensitivity curve of the photocell expressed in absolute units, and the
curve of encrey euxtributioo of the radiatios source at a definite temperature, like-
wise in absolute units.
In its general form, a photocurrent is defined by the expression
C.
.51
-
where n
Na
a c
?
?
.W.
'Pm Vykl "V*1.2. .21",,r( 7 rat rre ",1, ."T"' 4":"..r.;:.48.-"43)ft. o*. t.y.t...r.t" ?
ipl J j 4104,IMA
?
- -
is the proportionality fecter characterizing the electric properties of
the photocell; (Nc nunber of electrons esitted by cathode; Na nusber
of electrons reachiag the anode);
SA is the spectral sensitivity in amp/watt;
f(A,1) is the spectral energy distribution of the given radiator.
Since the quantities SA and n are strictly constant for a gives photocell, they
say be combined into a single parameter oA, which is called the spectral efficiency
of a photocell:
???
J elf(X,1)dX
?
(1'24)
If the value of the photocurrent is related to the unit of incident energy, he
lumen, then the integral sensitivity may be expressed by the.formela
S
eAf(X,T)Ot
?
'
f KAf(A.T/dA
1
where-? w670 is the luminous equivalent of the radiant flux;
(125)
KA is the spectral visibility factor;
The numerator in e.(125) is usually expressed in uaits of current, for in-
stance in microamperes (g amp) or ix amperes (amp), while the denominator is ex-
pressed in units of radiant flux, usual in watts (w).
Since it is difficult to determine the value of oA, tha simpler formula
*M.
.? -
'Phil Irk Pk
t a
mi la- -IF-
103
e
(126)
4
.X
4
:4
STAT
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1 ? ????????????
?
?
?
?
- ?-?2- ???.:??? . ? -? - ? arm." ? - . ? .
0001,417."0:4?!-IT*WVP V?rennPr?Welir?V?rd?r*"*.?U`i ???"0115,0' tqr.VrV=.4.0Var?"-.11?1"?-,./.-??? ..11,???1,-,?,???? ?? ?
1
is usually used for calculating the integral sensitivity.
*here Iph ? sasimum photocurrent; for a vacuu.s photocell, the sattration current;
* ? incident radiant flux in watts;
E . illumination in what; ,
S illuminated area of photocclls in mm2;
r . distance from radiation saurce to photocell in m;
Is luminous intensity of source in whiter.
values of the integral sensitivity of a few photocells produced in USSR are
Table M. The letters TsV denote oxygea-cesium vacuum photocells; the
Tali, gas-filled photocells.
The
given in
letters
Tablw 30
Integral Sensitivity of a Few Photocells
Type
Integral Sensitivity.
1.1 INV/in
taefal Liie,
Hours
TaV-1
20
203
TsV-2
20
200
TsG-1
75
700
Tarp-2
150
700
TaG-3
150
700
TaG-4
193
700
The data of Table 30 show that the integral sensitivity of vacuum photocells is
t :1 considerably less thaw. that of gas-fiiled photocells.
5
The integral sensitivity of gas-filled cells is increased by filling the tube
with an inert gas. %hinh leads to an increese of the photocurrent, due to an ioni-
zation of the gas by the photoelectrons moving frost the photocathode to the anode.
_ Section 47. Spectral Characteristic of Photocelln
The spectral characteristic is very importait for proper selection of a. photo-
_
cell and a radiator. The maximum efficiency of a system photocell-radiator is ob-
tained when the spectral sensitivity of the photocell corresponds to the spectral
a
C)
. . _ .
- energy distribution of the radiator.
The deterninetion of the opectral sensitivity in absolute units involves great
difficulty, since up to now there is no satisfactory uathemaLical formula for cal-
culating it. The spectral characteristic is therefore usually constructed in rela:
- tire units. In this case, the greatest of the maxima is conventionally taken as
_100%.
A cesium photocell has its maximum spectral zensitivity at 0.78 0, while the
.131
I*
201
01
ii
44
a)
.._
Fig. 44 - Spectral Sensitivity of a Cesium Photocell with Coated Cathode
_ a) lavelergth,u, L) Photocurrent in relative units
^
2 t
red boundary of its spectral characteristic is the infrared region runs up to 1.2 u.
Figure 44 gives the spectral sensitivity curve of a cesium photocell with
?
3.-
coated cathode. As will be seen from the diagram, the spectral characteristic of a
coated cesium photocathode has several ',alias, which is explained by the complex
chemical structure of the photocathode. The uniformity of the coating layer and the
' thickness of the intermediate layer ere very important for the characteristic. %hem
tie thickness of the intermediate layer iacreases, the steepness of tho maximum
rises, but this leads to the phenomenon of pilotocathode"fatigue, which will be
' considered below.
The cesium photocell, as will be sees from the diagram, is rather sensitive to
radiations of wavelengths up to ui,out 0.9 u, but its sensitivity drops sharply as.
the wavelength increases further.
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d.....* ..13g 44r4t ?ffnee 11111114111113eYsow_s...ft to -
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awe
Section 48. Gas Amplificatiou
As pointed out above, the increase in integral sensitivity, or photocurrent, of
a gas-filled photocell is accomplished by the ionization of a small amount of inert
gas introduced into the tube. The process of gas amplification in general outline,
.is as follows:
Shen a radiant flux is incident on the surface of a gas-filled photocell, the:
the liberated photoelectrons, on their path from the cathode to the anode, collide
4
b)3
0
I
_.
Fig. 45 - Relation of Photocurrent to Gas Pressure
a) Pressure, nm Hg; b) Photocurrent, a amp
with neutral gas molecules. Sheet in electron collides with a molecule, it becomes
ionized, i.e., a positive ion nnd an electron are formed. As a result, two dee-
__
trona will move toward the anode, while the positive ion will move towartrthe
- cathode. Successive collisions of electrons with the molecules of the gas lead to
an avalanche of electrons, i.e., to an increase in total photocurrent. The photo-
current is also increased owing to bombardment of the photocathode surface by posin
tiye ions. This might increase the photocurrent by a factor of 5 to 7,
crease leads to a rapid disintegration of the cathode.
Further ;
The ratio of the current intensity Ipk (produced by .the ionization) to the
stresgth of-the priaary photocurreat 10, is called the amplification factor:
1_
(127) -
9
r)
-
_ .
The gas amplification factor depends on the design of the photocell, the kind
.of gas, rind its pressure.
The gas charging the photocell must not interact with the photosensitive layer
of the photocell
gas must be low,
cuiremeets.
nor with the glass of the tube. The ionizatioh potential of the
so as to facilitate ionization. The inert gases meet these re-
Photocells are most often filled with
I t7?124,04._
--c+
;2 C3 Cf 45 4.1 C7 ;a to 417
a0
Fig 46 - Luminous Characteristics of
'vacuum Oxygen-Cesium Photocell at
Various Voltages
a) Luminous flux, le; b) Photo-
current, :r amp; c) 4 ? 200 volts
argon, which is the cheapest gas and
easily obtainable.
The pressure of the gas in the pho-
tocell is about 0.2 um Hg. then the gas
pressure is decmased, the collision
probability between electrons and mole-
cules diminishes, since the distances be-
tseera them increase.
11th increasing pressure, on the
other hand, the electrons may collide
with molecules without imparting suf-
ficient energy for ioeizatioe.
Figure 45 gives the curve of rela-
tion between photocurrent and gas pressure. At a pressure of 0.2 mm Pg, the so-
_
- called"Stoletov maximum* is obtained. Its position is determined by the length of
the mean free path of the electron betimes two collisions, and depends ua the desiga
: of the photocell.
Gas avlificatioa also L-s its usfavorsble properties: the linearity of the
luminous characteristics is destroyed and sluggishness of the photocurrest results.
-.Section 49. Luminous Characteristics of Photocells
- Lunimons Cherecteristics of Vacuum Photocell*
&patios (103) expresses the proportionality of photocurreat to the luminous
;?.-;Aolst on the surface, or illumination. This linear sciatica is valid only
STAT
in
. ?
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1 .
_
. ?
"ra 1att in?vgttorta.?WIR111Mtroadig24:10, - -
for relatively small luminous fluxes.
Figure 46 gives eive- luminous characteristics of a vacuum cr.lgen-cesium photocell
at various voltages. The curve shows that, at an insignificant luminous flux, the
linear relation i f(F) holds strictly,.
regardless of tbo. voltage.
pith increasing luminous flux the
linear relation is disturbed due to the
formation of chargee on the walls of the
tube and thrv formation of a space chargc,
as well as due to the influence of
'fatigue'.
It must be borne in mind that a photocathode is not uniformly sensitive at vari-
ous points of its surface.
Figure 47 shows the curve of variation in sensitivity for various points of an
oxygen-cesiun cathode, obtained by N.S.1(hlebnikov. and N.S.Zsytsev. The curve shows
- -irregular distribution of sensitivity along the surface of the photocell.
) wo
Fig.47 - Distribution of Sensitivity
of an Oxygen-Cesium Cathode along
its Surface
a) Distance along surface, mm;
b) Sensitivity
4
--Iominous Characteristics of Gas-Filled Photocells
In gas-filled photocells, the relation of photocurrent and luminous flux is
likewise nonlinear.
The luminous characteristics of
a gas-filled photocell, taken at various
voltages (Fig.48).. slow that, at in-reasing applitd voltage, the nonlinearity of the
characteristics increases. Ili: has to do with the increased ionization and the ap-
?roach to a state of independent gaseous discharge with increasing voltage.
At small luminous fluxes (up to 0.1 1m), the linear dependence i
rather strictly for gas-filled photocells.
- Section ,50. Volt-Ampere Characteristics of Photocells
. Volt-Am ere Characteristics of Vacuum Photocells
SILT
St.
holds
-
ra,otorells of any design the volt-sapere characteristic reaches
?
? --P..,,Tf4mtm="JM,W,
?
Z dn.
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