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Investigation of space angular and energy distribution of ions scattered by single crystal.
Classified abstracts 1 O-24 10. Secondary emission investigations of structural defects in m&la irmdiatwl hv mm __I. innr. IT I---- _ \_JSSR) _ I _ -, -_~l-l I-_-I___ I~ inert Using the method of secondary electron emission, formation structural defects in Ge crystals caused by bombardment with to 5 keV Xe+ ions and annealing of defects are investigated. I A Abroyan et al, Izv AN SSSR Ser Fiz, 37 (12), 1973, 2605-2608 Russian).
16 Ge of 2.5 (in
16 11. Energy losses of ions interacting with solid. (USSR) Using the Slater model of atom, the distribution of electron density in a crystalline lattice is obtained. Energy losses of light ions at plane charmelling are calculated. Energy losses of heavy ions are considered using a modified Firsov theory. F F Komarov and M A Kumakhov, Zzv AN SSSR Ser Fiz, 37 (12), 1973, 2578-1485 (in Russian). 16 12. Problems of the theory of interaction of ion beams with crystals. (USSR) Cnarc= Y&c.._
rlirtrihntinnr -.YbI.Y....“I-Y
nf “1
imnlantd -11. y--.w..
innr I”..”
anrl .._I
nrli&nn A.........“..
defprtf UVA_...
27~ ..I”
calculated at channeling of an ion beam in crystal. Distribution of flow of the chamrehing beam in the cell of lattice is also studied. M A Kumakhov and V A Muralev, Izv AN SSSR Ser Fiz, 37 (12), 1973,2585-2589 (in Russian). 16 13. The blocking effects at scattering of medium energy ions by crystals. (USSR) Influence of the blocking effects on the character of energy distribution of 10 to 30 keV argon ions scattered by a (110) copper face is investigated. E S Masbkova and V A Molchanov, Izv AN SSSR Ser Fiz, 37 (12), 1973,2568-2569 (in Russian). 16 14. On scattering of slow ions by solid surface. (USSR) Possibility of utilization of the model of pair subsequent collisions of the ion with two lattice atoms is studied in the region of low d..,%.,&%” l.n- -&-In+r\ PM cr, .%xn“I ,-.FtiJ r”+ l”llJ ;,-....- “II a” *La:.. ^^“**-..:..- I... Gl,nrj.rJ Ila,o \1=35lLuau L” VW LI1GLI JMLL=llllg vy atoms of tungsten single crystal. V I Veksler and V V Evstifeev, Izv AN SSSR Ser Fir, 37 (12), 1973, 2570-2572 (in Russian). 16 15. Investigation of space angular and energy distributions of ions scattered by single crystal. (USSR) Using the computer modelling of scattering of 12 to 30 keV argon ions on two neighbouring atoms of copper with distances corresponding to (100) and (110) axes, the ratio of single and double scattering is calculated. The results of calculations are compared with the experimental data. A Mukhamedov et al, Izv AN SSSR Ser Fir, 37 (12), 1973, 2562-2564 (in Russian). 16 16. Arrangement for investigation of interaction of charged particles with singie crystals. (USSR) ,~..._C_ .:_ c__-.._.. -e . ..*_ ._ _.._ in arrangemenr ror mvesugauon or mteracuon of charged particies with single crystals is described. The arrangement consists of a collimator, goniometer, monitor and surface-barrier detector with energy resolution of 28 keV. Energy of scattered particles is analysed in an analyser. N A Shakun et al, Prib Tekh Eksper, No 4, 1973, 49-50 (in Russian). 16 17. Cathodoluminescence observations of Al-rich Gal_.Al.As with high Si content. (Germany) Catholdoluminescence spectra were measured at pulsed 30 keV electron bombardment of silicon doped Gar_,A.lAs single crystals. T Hansel et al, Phys Stat Sol (a), 16 (l), 1973, K31-K34. 16 18. The shapes of irradiation-produced voids in nickel. (Germany) Voids were produced in vacuum-annealed and hydrogenated nickel by protons with energy up to 2 MeV and Ni++ ions at 500°C in vacuum of 1 x 10e6 torr or dry hydrogen. Transmission electron microscopes were used for observation of the shapes of voids. The wide variation in the shape of voids is attributed to the anisotropy of surface energy, the kinetics of growth of void surfaces and a preferentiai adsorption of carbon on the (iOQ surfaces. (USA) C W Cben, Phys Stat Sol (a), 16 (l), 1973, 197-210. 1
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18. GASEOUS 1Q M~aadno __. ..----..e
ELECTRONICS 18 thr --
IIYPI~I~~ Inn .....--L)-
~2s
ifi 2 #y... cms.diarharaa &m& . ..“_.....~’ with ,.-..a .a Y....F...
probe. (USA) The orbital theory of current-collection of a cylindrical Langmuir probes is applied to determine the average ion mass in a discharge. The analytical derivations are supplemented by experimental results. Applications are discussed. K H Geissler, Rev Sci Instrum, 45 (4), 1974, 604605. 18 20. Electron-optical imaging of high-j prebreakdown currents. (GB) An electron-optical technique has been developed to image the stable prebreakdown currents (- lo-” A) from an undamaged hairpin tungsten cathode at a temperature N 800°C and pressure N 10ds torr, the macroscopic surface field being d 5 x lo5 V cm-‘. Although the Fowler-Nordheim plots of such cathodes indicate typical enhancement factors (,9) of 2200 for the microscopic point emitters, the results of the present investigation indicate that the currents originate from extended-area emission sites in the form of rounded extrusion rirlnon,i tl..%.mo,,.r n+,+,n,i @ mn;no “~,-.rn~&..,“I nr JUtill -..,.l. IM,UITD F,%n+....-” llug”a (L1l1l rllrllllall, U&CIIWU Ylll.?, *La LI1W 6U”“‘“L’J giving 8 5 10. Independent measurements of the temperature dependence of the prebreakdown currents indicate that a RichardsonSchottky, rather than a Fowler-Nordheim mechanism offers an alternative explanation of such high-8 prebreakdown currents. C S Walters et al, J Phys D: Appl Phys, 7 (16), 1974,911-919. 18 21. Near-ultraviolet emission spectrum from an intense relativistic electron-beam discharge. (USA) Time-integrated emission spectra from the pulsed discharge of a 3.5-MeV electron beam, with 90-kA peak current of about 30-ns duration, and guided by a glass rod protruding from the cathode in a field-emitting diode, have been studied with a quartz-prism spectrograph. With anodes of graphite or polyethylene, the spectrum in the near-uv to visible rangeis found to consist mainly of-emission lines from C. C+. Cz+. and C?+. and similar ones from silicon. The snatial dependknce’of emission intensity indicates that a hot spot is present A..*:“” +l.a A:r^l.n..“n 11tiLLI .._nr tlra n..?.rl,%DUII(I_. o.l..+-n- Tl.n U._u,llP Lllr UlOCl.rn&~ CllU_Ll”UC lllr •~m-~..“+....rnlriJc’aLL&‘r-..A LIl,llrl., 1.11= electron density in the plasma are estimated through a theoretical analysis of the composition of carbon in the gas phase. P S P Wei et al, J Appl Phys, 45 (5) ,1974,2163-2167. 18 22. Current continuity in dense plasma. (USA) The equations of current continuity have been solved for highdensity (n,,. > lo’* cmm3) gaseous plasma as a problem associated with electron-beam-controlled electrically excited pulsed laser energy sources. The procedure used first-order numerical approximations to the space and time development of current and potential gradients. The results of a laser plasma study are (a) the total electron current is not very sensitive to electron emission at the cathode because (b) the sheath multiplies both secondary electrons and cathode current by a large factor and adjusts to current requirement set by electron mobility and density in the plasma. Small changes in the sheath thickness and potential drop satisfy the variable-current condition Langmuir
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The uotential droa in the sheath of an STP nlasma is 40@-2000 V for plasma currents of l-10 A/cm2, and the sheath thickness is d N 0.003 cm. C B Mills, J Appf Phys, 45 (5), 1974, 2112-2114. 18 23. Secondary electron yield with primary electron beam of kiloelectron-volts. (USA) Secondary electron yields S,, due to primary electrons of kiloelectron-volts are estimated for various metals by measuring total electron yields 8, in an UHV system and using a Monte Carlo calculation to derive 8pe from &. The dependences of 6r/Spe as well as &.e on both the atomic number Z and primary energy are also discussed from a theoretical viewpoint based on the Monte Carlo technique for primary energies higher than a few keV and on a simple theory for iower primary energies. (Japan) R Shimim, J Appl Phys, 45 (5), 1974,2107-2111. 18 24. Investigation of the energy and impurity content of a crossed-field plasma gun. (USA) The downstream energy and impurity content of the piasma produced by a pulsed crossed-field source is investigated. With a positive centre 35
16 Ge of 2.5 (in
16 11. Energy losses of ions interacting with solid. (USSR) Using the Slater model of atom, the distribution of electron density in a crystalline lattice is obtained. Energy losses of light ions at plane charmelling are calculated. Energy losses of heavy ions are considered using a modified Firsov theory. F F Komarov and M A Kumakhov, Zzv AN SSSR Ser Fiz, 37 (12), 1973, 2578-1485 (in Russian). 16 12. Problems of the theory of interaction of ion beams with crystals. (USSR) Cnarc= Y&c.._
rlirtrihntinnr -.YbI.Y....“I-Y
nf “1
imnlantd -11. y--.w..
innr I”..”
anrl .._I
nrli&nn A.........“..
defprtf UVA_...
27~ ..I”
calculated at channeling of an ion beam in crystal. Distribution of flow of the chamrehing beam in the cell of lattice is also studied. M A Kumakhov and V A Muralev, Izv AN SSSR Ser Fiz, 37 (12), 1973,2585-2589 (in Russian). 16 13. The blocking effects at scattering of medium energy ions by crystals. (USSR) Influence of the blocking effects on the character of energy distribution of 10 to 30 keV argon ions scattered by a (110) copper face is investigated. E S Masbkova and V A Molchanov, Izv AN SSSR Ser Fiz, 37 (12), 1973,2568-2569 (in Russian). 16 14. On scattering of slow ions by solid surface. (USSR) Possibility of utilization of the model of pair subsequent collisions of the ion with two lattice atoms is studied in the region of low d..,%.,&%” l.n- -&-In+r\ PM cr, .%xn“I ,-.FtiJ r”+ l”llJ ;,-....- “II a” *La:.. ^^“**-..:..- I... Gl,nrj.rJ Ila,o \1=35lLuau L” VW LI1GLI JMLL=llllg vy atoms of tungsten single crystal. V I Veksler and V V Evstifeev, Izv AN SSSR Ser Fir, 37 (12), 1973, 2570-2572 (in Russian). 16 15. Investigation of space angular and energy distributions of ions scattered by single crystal. (USSR) Using the computer modelling of scattering of 12 to 30 keV argon ions on two neighbouring atoms of copper with distances corresponding to (100) and (110) axes, the ratio of single and double scattering is calculated. The results of calculations are compared with the experimental data. A Mukhamedov et al, Izv AN SSSR Ser Fir, 37 (12), 1973, 2562-2564 (in Russian). 16 16. Arrangement for investigation of interaction of charged particles with singie crystals. (USSR) ,~..._C_ .:_ c__-.._.. -e . ..*_ ._ _.._ in arrangemenr ror mvesugauon or mteracuon of charged particies with single crystals is described. The arrangement consists of a collimator, goniometer, monitor and surface-barrier detector with energy resolution of 28 keV. Energy of scattered particles is analysed in an analyser. N A Shakun et al, Prib Tekh Eksper, No 4, 1973, 49-50 (in Russian). 16 17. Cathodoluminescence observations of Al-rich Gal_.Al.As with high Si content. (Germany) Catholdoluminescence spectra were measured at pulsed 30 keV electron bombardment of silicon doped Gar_,A.lAs single crystals. T Hansel et al, Phys Stat Sol (a), 16 (l), 1973, K31-K34. 16 18. The shapes of irradiation-produced voids in nickel. (Germany) Voids were produced in vacuum-annealed and hydrogenated nickel by protons with energy up to 2 MeV and Ni++ ions at 500°C in vacuum of 1 x 10e6 torr or dry hydrogen. Transmission electron microscopes were used for observation of the shapes of voids. The wide variation in the shape of voids is attributed to the anisotropy of surface energy, the kinetics of growth of void surfaces and a preferentiai adsorption of carbon on the (iOQ surfaces. (USA) C W Cben, Phys Stat Sol (a), 16 (l), 1973, 197-210. 1
._
.I
--.l_-..-
18. GASEOUS 1Q M~aadno __. ..----..e
ELECTRONICS 18 thr --
IIYPI~I~~ Inn .....--L)-
~2s
ifi 2 #y... cms.diarharaa &m& . ..“_.....~’ with ,.-..a .a Y....F...
probe. (USA) The orbital theory of current-collection of a cylindrical Langmuir probes is applied to determine the average ion mass in a discharge. The analytical derivations are supplemented by experimental results. Applications are discussed. K H Geissler, Rev Sci Instrum, 45 (4), 1974, 604605. 18 20. Electron-optical imaging of high-j prebreakdown currents. (GB) An electron-optical technique has been developed to image the stable prebreakdown currents (- lo-” A) from an undamaged hairpin tungsten cathode at a temperature N 800°C and pressure N 10ds torr, the macroscopic surface field being d 5 x lo5 V cm-‘. Although the Fowler-Nordheim plots of such cathodes indicate typical enhancement factors (,9) of 2200 for the microscopic point emitters, the results of the present investigation indicate that the currents originate from extended-area emission sites in the form of rounded extrusion rirlnon,i tl..%.mo,,.r n+,+,n,i @ mn;no “~,-.rn~&..,“I nr JUtill -..,.l. IM,UITD F,%n+....-” llug”a (L1l1l rllrllllall, U&CIIWU Ylll.?, *La LI1W 6U”“‘“L’J giving 8 5 10. Independent measurements of the temperature dependence of the prebreakdown currents indicate that a RichardsonSchottky, rather than a Fowler-Nordheim mechanism offers an alternative explanation of such high-8 prebreakdown currents. C S Walters et al, J Phys D: Appl Phys, 7 (16), 1974,911-919. 18 21. Near-ultraviolet emission spectrum from an intense relativistic electron-beam discharge. (USA) Time-integrated emission spectra from the pulsed discharge of a 3.5-MeV electron beam, with 90-kA peak current of about 30-ns duration, and guided by a glass rod protruding from the cathode in a field-emitting diode, have been studied with a quartz-prism spectrograph. With anodes of graphite or polyethylene, the spectrum in the near-uv to visible rangeis found to consist mainly of-emission lines from C. C+. Cz+. and C?+. and similar ones from silicon. The snatial dependknce’of emission intensity indicates that a hot spot is present A..*:“” +l.a A:r^l.n..“n 11tiLLI .._nr tlra n..?.rl,%DUII(I_. o.l..+-n- Tl.n U._u,llP Lllr UlOCl.rn&~ CllU_Ll”UC lllr •~m-~..“+....rnlriJc’aLL&‘r-..A LIl,llrl., 1.11= electron density in the plasma are estimated through a theoretical analysis of the composition of carbon in the gas phase. P S P Wei et al, J Appl Phys, 45 (5) ,1974,2163-2167. 18 22. Current continuity in dense plasma. (USA) The equations of current continuity have been solved for highdensity (n,,. > lo’* cmm3) gaseous plasma as a problem associated with electron-beam-controlled electrically excited pulsed laser energy sources. The procedure used first-order numerical approximations to the space and time development of current and potential gradients. The results of a laser plasma study are (a) the total electron current is not very sensitive to electron emission at the cathode because (b) the sheath multiplies both secondary electrons and cathode current by a large factor and adjusts to current requirement set by electron mobility and density in the plasma. Small changes in the sheath thickness and potential drop satisfy the variable-current condition Langmuir
__I
l_..
SOL oy
_^_
girs
:^_f__r:__ l”I,,Lau”11
___I
auu
:__
,011
_^^_-_l_:__*:__.
‘cG”Ill”lIlau”‘l.
,
1 =
._^...
New
_...
=
ew
I~,..\112
(J,“,-‘-.
The uotential droa in the sheath of an STP nlasma is 40@-2000 V for plasma currents of l-10 A/cm2, and the sheath thickness is d N 0.003 cm. C B Mills, J Appf Phys, 45 (5), 1974, 2112-2114. 18 23. Secondary electron yield with primary electron beam of kiloelectron-volts. (USA) Secondary electron yields S,, due to primary electrons of kiloelectron-volts are estimated for various metals by measuring total electron yields 8, in an UHV system and using a Monte Carlo calculation to derive 8pe from &. The dependences of 6r/Spe as well as &.e on both the atomic number Z and primary energy are also discussed from a theoretical viewpoint based on the Monte Carlo technique for primary energies higher than a few keV and on a simple theory for iower primary energies. (Japan) R Shimim, J Appl Phys, 45 (5), 1974,2107-2111. 18 24. Investigation of the energy and impurity content of a crossed-field plasma gun. (USA) The downstream energy and impurity content of the piasma produced by a pulsed crossed-field source is investigated. With a positive centre 35