Rod cathode of lanthanum hexaboride

Rod cathode of lanthanum hexaboride

Classified abstracts 560-574 radiation. A discharge quartz tube filled with nitrogen to pressure 500 torr and cesium vapour to 10e3 torr was used as...

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Classified abstracts

560-574

radiation. A discharge quartz tube filled with nitrogen to pressure 500 torr and cesium vapour to 10e3 torr was used as an efficient source of ultraviolet radiation. (USSR) E A Muratov et al, Proc of 11th Znternat Conf on Phenom in Zoniz Gases, Prague 1973, 11. 18 560. Vibrational temperature in molecular discharge plasmas. (Czechoslovakia) The results of measurements of vibrational temperature by the line reversal method and the method of relative intensities in 2+ system of Nz in C02-N2-He mixture at the ratio of components of 2: 1: 8 and total pressure 4 torr in dependence on the discharge current are compared. (USSR) V N Ocbkin, Proc of 11th Znternat Conf on Phenom in Zoniz Gases, Prague 1973,12. 18 561. On the potentialities of the application of Tikhonov regularization method for calculation of electric energy distribution density. (Czechoslovakia) Using the Tikhonov regularization method, electron energy distribution density for positive column of arc discharge in the mixture of helium at pressure below 1 torr and sodium vapours at pressure below 4.8 x 10m3 torr is calculated on the basis of data on intensities of NaI and He1 lines. It is shown that the calculated results agree with the experimental data obtained by the method of second derivative of probe current. A M Devyatov et al, Proc of 11th Znternat Conf on Phenom in Zoniz Gases, Prague 1973, 13. 18 562. Additional excitation and ionization in N, and Ar + Nz by diffusion of excited and charged species. (Czechosolovakia) Additional excitation and ionization in Nz and Ar + Nz mixture at pressures of 1 to 3 torr are investigated. An experimental arrangement with the measured glow discharge, the auxiliary discharge and platinum detector of excited molecules is described. J Janca and A Talsky, Proc of 11th Znternat Conf on Phenom in Zoniz Gases, Prague 1973, 15. 18 563. Experimental investigation of xenon excitation and ionization in electron-atom collisions. (Czechoslovakia) Excitation and ionization of xenon are investigated in a coaxial channel at electron-atom collisions in the thermally ionized gas flow at xenon pressure of 10 torr. (USSR) R V Vasilieva et al, Proc of 11th Znternat Conf on Phenom in Zoniz Gases, Prague 1973, 17. 18 564. Investigation of the frequency dependence of the multiphoton ionization of the metastable helium atoms. (Czechoslovakia) The frequency dependence of the multiphoton ionization of the metastable helium atoms, obtained in a dc gas discharge in helium at pressure of several torr, is investigated. J Bakes et al, Proc of 11th Znternat Conf on Phenom in Zoniz Gases, Prague 1973, 19. 18 565. Resonant multiphoton ionization of a caesium atomic beam by a tunable wavelength Q-switched neodymium laser. (Czechoslovakia) Three-photon excitation of the 6f level of caesium is experimentally observed at intercation between the tunable wavelength Q-switched neodymium laser beam and a caesium atomic beam. (France) J Morellec, Proc of 11th Znternat Conf on Phenom in Zoniz Gases, Prague 1973,22. 18 566. Multipboton ionization of molecular caesium with a tuneable dye laser. (Czechoslovakia) Two-photon ionization of molecular caesium was experimentally observed in a caesium cell operated at a saturated vapour pressure corresponding to 490” K and irradiated with a beam from a tuneable dye laser. C B Collins et al, Proc of 11th Znternat Conf on Phenom in Zoniz Gases, Prague 1973,24. 18 567. Electronic recombination and tbe effects of metastahles ln a helium afterglow. (Czechoslovakia) Electronic recombination and the effects of metastables are experi-

mentally studied in a helium afterglow at helium pressures ranging from 15 to 55 torr. (USA) A W Johnson and J B Gerardo, Proc of 1 lth Znternat Conf on Phenom in Zoniz Gases, Prague 1973, 30. 18 568. Spectra emitted in a high pressure electron-beam excited recombining helium afterglow. (Czechoslovakia) Spectra emitted in recombining helium afterglows at neutral pressures of one to five atmospheres are investigated. The experimental facility employs standard ultrahigh vacuum components throughout and is capable of evacuation to 10-l’ torr and bakeout to 400°C. Ultrahigh purity helium test gas was introduced at the operating pressure into a test cell fitted with a 0.001” titanium window. Excitation of the test gas was provided by a 10 Joule, 3 nanosecond pulse of 500 keV electrons. (USA) C B Collins et al, Proc of 11th Znternat Conf on Phenom in Zoniz Gases, Prague 1973, 31. 18 569. The dependence of the coefficient of potential ion-electron emission of metals on the parameters of target and ion. (USSR) The dependence of the coefficient of potential ion-electron emission from metals on work function, Fermi energy and ionization potential of the ion is considered. It is shown that theoretical considerations agree with the experimental data. L M Kishinevskls and R R Rakbimov. Phvs Phenom at Bomb of Solid Surf by Atomic Part, Vol 1, Coil, hAN.Tashkent 1973, 139-15; (in Russian). 18 570. Obtaining volt-ampere characteristics of integral electron emission induced by laser-irradiation of metals. (USSR) Volt-ampere characteristics of integral electron emission induced by laser-irradiation of metals have been obtained for various densities of power of laser irradiation and at various time periods. It is found that at low surface temperatures the current of integral electron emission is dependent on the collector voltage according to the 3/2 law. U A Arifov et al, Phys Phenom at Bombard of Solid Surf by Atomic Part, Vol 1, Cal, FAN Tashkent 1973, 164171 (in Russian). 18 571. Determination of thermionic parameters of faces of molybdenum single crystal. (USSR) Using the methods of Richardson line and positive surface ionization of sodium, thermionic parameters of (llO), (112), (100) and (111) faces of molybdenum single crystal have been determined. N G Imanaulova and E P Svtaya. Zzu AN UzSSR Ser Fiz Mat Nauk. No 5, 197% 70-71 (in Russ&): ’ 18 572. Field enhanced transmission secondary electron emission of porous LiF films. (USSR) Inertia-less field enhanced transmission secondary electron emission of porous LiF films is investigated in dependence on film thickness and energy of primary electrons. The LiF films have been prepared by sputtering in argon. The values of the coefficients of transmission secondary electron emission as high as 17 to 32 have been measured at energies of primary electrons of 3 to 5 keV. N L Yasnopolskiy et al, Radiotekh Elektron, 19 (4), 1974, Sol-807 (in Russian). 18 573. Secondary electron emission of evaporated platinum-barium alloy. (USSR) Secondary electron emission of platinum-barium alloy is investigated in the range of primary electron energy of 0.1 to 2 keV. The alloy has been prepared by simultaneous evaporation of Pt and Ba in ultrahigh vacuum of 1 x 10e9 to 5 x lo-” torr. It is shown that the high secondary emission efficiency in the region of optimum Ba concentration of about 5 o/ois due to formation of a Ba mono-layer on surface of the alloy. I M Bronshteyo et al, Radiotekh Elektron, 19 (4), 1974, SOS-811 (in Russian). 18 574. Rod cathode of lanthanum hexaboride. (USSR) Lanthanum hexaboride thermionic cathodes are described which are used in electron microscopes and microprobes. Construction of a cathode assembly containing a lanthanum hexaboride rod with 1 mm 179

Classified

abstracts

575-587

diameter and a heating tungsten foil with thickness of 20 pm is described. A N Kabanov et al, Proc of 9th All-Union Conf on Electron Microsc, Tbilisi 1973, 113 (in Russian). 18:30 575. Thii-lIlrn MIM system as a cold cathode. (USSR)

Thin-film system Al-&N&l is investigated in the mode of injection of hot electrons. The thin fdm Si3N4 has a high electrical strength and the top aluminium electrode with 100 8, thickness is semitransparent. The basic processes at operation of the thin-am cold cathode are formed by tunnel emission of electrons from the lower electrode in the conduction band of dielectric and by heating of electron gas by electric field. Thin-&n cold cathodes for vacuum integrated circuits and cathode ray tubes were developed and examined. G A Vorobev et al, Proc of All-Union Conf on Dielectric Electronics, FAN Tashkent 1973, 40 (in Russian). 576. Photogeneration of carriers and emission MIS structures. (USSR)

18 of hot electrons from

Operation of a thin-film system metal-insulator-semiconductor as a converter of optical signal (image) into emission of electrons into vacuum is considered. Elementary processes as photogeneration of carriers in semiconductor, their injection into dielectric, acceleration in dielectric and emission into vacuum through an ultrathin metallic electrode are discussed. F M Benson and Yu B Yankevich, Proc of AlI- Union conf on Dielectric Electronics, FAN Tashkent 1973; 29-30-(in Russian). 18 577. Destruction

of crystalline emitters by electrons. (USSR)

The results of investigation of variations in the coefficients of secondary electron emission and quantum yields of alkaline earth metal oxides at their irradiation with electrons are presented. It is found that the variations in the coefficient of secondary electron emission at room temperature are due to generation of colour centres and at elevated temneratures due to thinning of emitting oxide layer. Ways for increasing current stability of secondary emitters are proposed. A M Tyatikov, Co11of Works Dedic to 80 Annivers of Birth of Acad A A Lebedev, Mashinostroenie Leningrad 1973, 162-174 (in Russian).

II. Vacuum 25. BAFFLES

apparatus

and auxiliaries

TRAPS AND REFRIGERATION

EQUIPMENT 25

578. Cooled sorption trap. (USSR) Construction of a sorption trap with conductivity of 100 l/set and cooled with liquid nitrogen is described. Titanium plates with oxidized surface are used as sorbent. For degassing walls and for regeneration of the sorbent the trap is heated to 400°C. The trap is intended for protection of evacuated volume against vapours and cracking products of diffusion pump oils. The trap enables one to maintain pressure of less than 2 x 10T9 torr without presence of hydrocarbons. S F Grishin et al, Probl of Atomic Science and Technol, No 1, Co& Kharkov 1973, 51-54 (in Russian).

28 580. Temperature determination of thin sapphire substrates. (USA) A technique is presented which allows for a noncontact temperature

determination of thin sapphire substrates with ordinary laboratory instrumentation. The technique utilizes the property of expansion with temperature. A calibration curve of sapphire substrate temperature vs heater temperature is deduced. This calibration scheme can be used for other substrate materials which are transparent in the visible region such as fused silica, glass, and many crystals for which thermal expansion data are known. EL Paradis and A J Shuskus, J Vat Sci TechnoI, 11(4), 1974,824-825. 581. Measurement of temperature bead thermocouple. (USSR)

28 of a flow of rarefied gas by multi-

Physical bases of utilization of a multi-bead thermocouple for investigation of nonisothermal flows of rarefied gases are given. D P Lebedev and E F Andreev, Zzv VU2 Priborostr, 16 (ll), 1973, 119-l 23 (in Russian). 28 582. A vacuum furnace for growth of single crystals of alloys by the Bridgman method. (USSR)

A vacuum furnace for growth of single crystals of alloys by the Bridgman method at temperatures upto ISbOY and a vacuim of 10d3 torr is described. The oossibilitv of utilization of black bodv as an absorber of heat energy-for producing a high axial tempera&e gradient is shown. Single crystals of iron-nickel alloys with high uniformity of orientation along the whole length have been grown in the furnace. V I Karmanchuk, Rep of Kirgiz Univers Phys Sciences, No 2, 1973, 52-57 (in Russian).

Ill.

Vacuum

applications

30. EVAPORATION

AND SPUTTERING

30 583. Local heteroepitaxial films prepared by electron-beam technology. (USSR) Local heteroepitaxial Ge films on Si have been prepared by means of electron-beam technology. The dependence of quality of prepared films on technological conditions during deposition is shown. The results of investigation of structure, surface morphology and electrophysical properties of the prepared films are presented. A P Dostanko et al, Electron Obrab Mater, No 6, 1973, 61-63 (in Russian). 30 584. Formation

of phases in Ni/Si lilms. (Germany)

Formation of phases in thin Ni/Si films during annealing is investigated in an electron microscope. Subsequent electron-beam evaporation of Si and Ni was carried out in a vacuum of 10e5 torr on glass substrates with previously deposited SiOZ layer. It is found that phase transformations in the studied films are determined by kinetics of transformations and not by thermodynamic stability. U Beck et al, Krist und Techn, 8 (lo), 1973, 1125-1129 (in German). 30 585. On structure of PbTe thin 6bns. (USSR)

28. HEATING

EQUIPMENT

AND THERMOMETERS 28 intermetallic evaporation

579. Power requirements of resistance-heated sources. (USA) There is a need in the metallizing industry for a rapid method, based on sound theory, for determining the voltage and current requirements for the operation of resistance-heated intermetallic aluminium evaporation boats. This paper shows how these power requirements can be adequately predicted in terms of operating temperature, two partially reduced dimensional parameters and the resistivity of the composite material. A solution of the total heat-flow equation for a model situation with appropriate simplifications and assumptions is presented. Experimental data are fitted to this simplified equation and the resultant calculated data are presented in graphical form suitable for generating computer tabulated data for all possible boat geometries and resistivities of Sylvania Intermetallic Composites No 17 or No 18. E D Parent, J V&u Sci Technol, 11 (4), 1974, 820-823. 180

Using the method of electron diffraction, structure of thin (lOO600 A) PbTe thin films, prepared by vacuum condensation on NaCl substrates covered with carbon layers, is investigated. The deposition temperature of PbTe films was varied in the range of 300 to 570°K. E V Rakova and S A Semiletov, Kristalograf, 18 (6), 1973, 1272-1274 (in Russian). 30 586. Nucleation of defects at gallium arsenide epitaxy. (USSR)

Using the methods of replica electron microscopy, the process of nucleation of defects at early stages of GaAs thin film epitaxial growth in the svstem Ga-AsCl,-HZ is investigated in dependence on the treatment of substrate. L G Lavrenteva et al, Struct Defects in Semicon, Coil, Novosibirsk 1973, 50-53 (in Russ&). 30 587. Field effect in indium nitride. (USSR)

The field effect is investigated in indium nitride films evaporated on surface of ferroelectric ceramics of lead titanate-zirconate or barium