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256. On the mechanism of establishment of the electron energy distribution in the plasma of a negative glow discharge
Classified abstracts 247-258 atomically clean (1 I0) face of molybdenum single crystal was deter. mined to be 5.0 eV, using the thermionic method. The dependence of the work function of the system M o ( l l 0 ) ÷ L a on the evaporation time was determined with observation of diffraction during evaporation on to the cold substrate. It was found that the first lanthanum atoms provide a regular structure, c(3 × 1), with an island character. Further evaporation results in domain formation with an elementary (2 × 1) cell. The structure of the system Mo(110)+La corresponding to the minimum value of the work function of 2.8 eV gives only the patterns of lanthanum and molybdenum. Further increase of the lanthanum concentration produces a new lanthanum hexagonal structure corresponding to the (0001) face. Still further evaporation results in growth of crystals of ~-lanthanum. Heating the system to 800-1000 K leads to background disappearance. Increase of temperature to 1100-1400 K results in evaporation of the outer layer of adatoms and the structure c(2 × I) is stable to 1300 K. At 1450 K, the lanthanum atoms are fully vaporized. B V Bondarenko and V I Makhov, Fiz Tverd Tela, 12 (7), July 1970, 2072-2075 (in Russian). 16 247. Application of alumina to adsorption problems. (Hungary) Properties of activated alumina manufactured in Hungary and used for dehydration of gases are determined. A Lux, Magyar Aluminium, 6 (9), 1969, 269-270 (in Hungarian). 16:20 248. Properties of non-sputtered gas absorbers. (USSR) The gas-absorption characteristics of porous titanium mouldings and five analogous composition materials in oil-free vacuum systems at a pressure of 10-8 mm Hg (torr) are considered and their relative performances at 600°C are presented. As the active components of the air are absorbed by these materials, the relative rate of carbon dioxide absorption diminishes over a period of time, and at 200-400°C methane is evolved. A vibrational method is proposed for testing the mechanical strength of the mouldings together with their heat resistance; this procedure may conveniently be combined with chemical analysis of the contaminated parts. V F Popov, Electronic Technology, Scientific-Technical Collection of ,4rticles on UHF Electronics, 1970, No 7, 150-153 (in Russian). 18. GASEOUS ELECTRONICS 18 249. Investigation of positive ion emission from tungsten filaments with the aid of a time-of-flight mass spectrometer. (Hungary) The thermal positive ion emission from tungsten filaments has been studied to obtain additional information on interactions between dislocations and ion emission. The absolute values of the ion currents, the parameters of ion bursts and the ratio of steady to burst-like emission are determined as dependent on crystal structure. O Kaposi et hi, Magyar Kemiai Folyoirat, 75 (7), 1969, 324-330 (in
Hungarian). 18 250. Experimental study of positive ion emission from tungsten. 1. (Hungary) Positive ion emission from heated metals is measured with the aid of a time-of-flight mass spectrometer. The method permits determination of the nature of emitted ions and also the study of the very fast processes involved. The mechanism of positive ion emission from heated spiral tungsten filaments is studied in detail by measuring the temperature and time dependence of emission of both un-preheated and annealed spirals. Measurements on molybdenum give curves corresponding to those obtained for tungsten. Continuous and impulse-like burst ion currents are measured. The height and shape of the ion burst pulses and the number of ions creating the pulses are evaluated for different temperatures. Comparing the results of measurements for single crystal and polycrystalline material yields information on the role of additive materials and their position in tungsten. O Kaposiand M Riedel, .4 eta Chim ,4cad Sci Hung, 61 (4), 1969, 349-366. 18 251. A diagnostic system for the cathode-side examination of oxide cathode arc discharges. (Hungary) A diagnostic system for study of the cathode-side oxide-cathode arc discharge at low pressure is presented which incorporates ten methods of measurement. I Bito, Hiradastech Ipari Kutato Intezet Kozl, 9 (1), 1969, 13-38 (in
Hungarian).
18 252. Determination of the absolute value of the emission ion current with a time-of-flight mass spectrometer. (Hungary) The thermal ion emission from incandescent tungsten filaments was examined with the aid of a time-of-flight mass spectrometer. Various heating rates of the filaments were controlled by an electronic circuit and the filament temperature was recorded simultaneously with the mass spectrum. The absolute values of the positive ion emission of poly- and monocrystalline tungsten filaments were determined after mass spectrometer calibration. It is found that ion emission of heat treated tungsten filaments occurs mainly in the form of ion bursts. O Kaposi, Meres ,4utomatika, 17 (5), 1969, 177-181 (in Hungarian). 18 253. Functional parameters of oxide cathodes in are discharges and their correlation. (Hungary) Low-pressure mercury vapour-argon arc discharge with oxide cathodes is investigated. A correlation between the work function, spot temperature, ion current density, spot surface and emission current of the cathode is found. I F Bito, ,4cta Teeh ,4cadSeiHung, 65 (1-2), 1969, 79-98 (in German). 18 254. Charge exchange of protons in caesium to negative ions. (USSR) On the basis of theoretical considerations, it is shown experimentally that a caesium vapour stream can be used for charge exchange of Ht + to 1-11-with a high efficiency of 0.26, in the low energy range. Yu M Khirnyi and L N Kochemasova, Prib Tekh Eksper, Nr 3, May~iune 1970, 56-58 (in Russian). 18 255. General threshold theory of electron emission from the surface of a metal. (Germany) A unified theory of field, thermionic and photoelectron emission from the metal surface into vacuum, dielectric or electrolyte is developed which is based on the use of methods of calculation of the threshold phenomena in quantum mechanics. As a result, the corresponding final expressions are obtained in such a form that it is possible to apply immediately the well known methods of scattering theory for their investigation. The known formulae of the electron emission theory are corrected and some new results are obtained, which are in quantitative agreement with experiment. (USSR) A M Brodskii et el, Phys Star Sol, 40 (1), July 1970, 139-151. 18 256. On the mechanism of establishment of the electron energy distribution in the plasma of a negative glow discharge. (USSR) The electron energy distribution function in the plasma of a negative glow discharge in inert gases at low pressures from 0.I to 12 torr, was experimentally investigated. G S Sointsev et al, Radiotekh Elektron, 15 (9), Sept 1970, 1980-1982
(in Russian). 18 257. Angular regularities in ion-electron emission from niobium single crystals. (USSR) The angular dependence of secondary electron emission from the (111) face of niobium single crystal was measured for bombardment by 25 keV argon ions. Experiments are carried out with the aid of a mass monochromator with an ion beam energy spread of 9 × 10 -3. The ion current density on the target was 0.2 to 0.3 mA/cm ~, and pressure in the analyzer chamber was lower than 2 × 10-~ torr. Under these conditions, the influence of gas adsorption at the target surface on the results is small, because the ion flux on the target predominates over the particle flux from ambient. The target was mainrained at a temperature of 450°C during measurement. Secondary electrons were measured with the aid of a Faraday cylinder. The angular resolution of the analyzer system was 3 deg. Maxima and minima due to target crystal structure were found in the angular distribution of secondary electrons. L B Begrambekov et al, Fiz Tverd Tela, 12 (7), July 1970, 2178-2179
(in Russian). 18:30 258. Electron inelastic scattering and secondary electron emission of magnesium and magnesium oxide. (USSR) Results of experimental investigations of secondary electron emission from thin magnesium and magnesium oxide films are reported. Magnesium films were prepared by vacuum evaporation at 10-8 torr on a tantalum substrate cooled by liquid oxygen. Magnesium oxide layers were prepared by oxidation of thick and thin magnesium films in an oxygen atmosphere at 3 × 10-a torr. Temperature was gradually 18g
Hungarian). 18 250. Experimental study of positive ion emission from tungsten. 1. (Hungary) Positive ion emission from heated metals is measured with the aid of a time-of-flight mass spectrometer. The method permits determination of the nature of emitted ions and also the study of the very fast processes involved. The mechanism of positive ion emission from heated spiral tungsten filaments is studied in detail by measuring the temperature and time dependence of emission of both un-preheated and annealed spirals. Measurements on molybdenum give curves corresponding to those obtained for tungsten. Continuous and impulse-like burst ion currents are measured. The height and shape of the ion burst pulses and the number of ions creating the pulses are evaluated for different temperatures. Comparing the results of measurements for single crystal and polycrystalline material yields information on the role of additive materials and their position in tungsten. O Kaposiand M Riedel, .4 eta Chim ,4cad Sci Hung, 61 (4), 1969, 349-366. 18 251. A diagnostic system for the cathode-side examination of oxide cathode arc discharges. (Hungary) A diagnostic system for study of the cathode-side oxide-cathode arc discharge at low pressure is presented which incorporates ten methods of measurement. I Bito, Hiradastech Ipari Kutato Intezet Kozl, 9 (1), 1969, 13-38 (in
Hungarian).
18 252. Determination of the absolute value of the emission ion current with a time-of-flight mass spectrometer. (Hungary) The thermal ion emission from incandescent tungsten filaments was examined with the aid of a time-of-flight mass spectrometer. Various heating rates of the filaments were controlled by an electronic circuit and the filament temperature was recorded simultaneously with the mass spectrum. The absolute values of the positive ion emission of poly- and monocrystalline tungsten filaments were determined after mass spectrometer calibration. It is found that ion emission of heat treated tungsten filaments occurs mainly in the form of ion bursts. O Kaposi, Meres ,4utomatika, 17 (5), 1969, 177-181 (in Hungarian). 18 253. Functional parameters of oxide cathodes in are discharges and their correlation. (Hungary) Low-pressure mercury vapour-argon arc discharge with oxide cathodes is investigated. A correlation between the work function, spot temperature, ion current density, spot surface and emission current of the cathode is found. I F Bito, ,4cta Teeh ,4cadSeiHung, 65 (1-2), 1969, 79-98 (in German). 18 254. Charge exchange of protons in caesium to negative ions. (USSR) On the basis of theoretical considerations, it is shown experimentally that a caesium vapour stream can be used for charge exchange of Ht + to 1-11-with a high efficiency of 0.26, in the low energy range. Yu M Khirnyi and L N Kochemasova, Prib Tekh Eksper, Nr 3, May~iune 1970, 56-58 (in Russian). 18 255. General threshold theory of electron emission from the surface of a metal. (Germany) A unified theory of field, thermionic and photoelectron emission from the metal surface into vacuum, dielectric or electrolyte is developed which is based on the use of methods of calculation of the threshold phenomena in quantum mechanics. As a result, the corresponding final expressions are obtained in such a form that it is possible to apply immediately the well known methods of scattering theory for their investigation. The known formulae of the electron emission theory are corrected and some new results are obtained, which are in quantitative agreement with experiment. (USSR) A M Brodskii et el, Phys Star Sol, 40 (1), July 1970, 139-151. 18 256. On the mechanism of establishment of the electron energy distribution in the plasma of a negative glow discharge. (USSR) The electron energy distribution function in the plasma of a negative glow discharge in inert gases at low pressures from 0.I to 12 torr, was experimentally investigated. G S Sointsev et al, Radiotekh Elektron, 15 (9), Sept 1970, 1980-1982
(in Russian). 18 257. Angular regularities in ion-electron emission from niobium single crystals. (USSR) The angular dependence of secondary electron emission from the (111) face of niobium single crystal was measured for bombardment by 25 keV argon ions. Experiments are carried out with the aid of a mass monochromator with an ion beam energy spread of 9 × 10 -3. The ion current density on the target was 0.2 to 0.3 mA/cm ~, and pressure in the analyzer chamber was lower than 2 × 10-~ torr. Under these conditions, the influence of gas adsorption at the target surface on the results is small, because the ion flux on the target predominates over the particle flux from ambient. The target was mainrained at a temperature of 450°C during measurement. Secondary electrons were measured with the aid of a Faraday cylinder. The angular resolution of the analyzer system was 3 deg. Maxima and minima due to target crystal structure were found in the angular distribution of secondary electrons. L B Begrambekov et al, Fiz Tverd Tela, 12 (7), July 1970, 2178-2179
(in Russian). 18:30 258. Electron inelastic scattering and secondary electron emission of magnesium and magnesium oxide. (USSR) Results of experimental investigations of secondary electron emission from thin magnesium and magnesium oxide films are reported. Magnesium films were prepared by vacuum evaporation at 10-8 torr on a tantalum substrate cooled by liquid oxygen. Magnesium oxide layers were prepared by oxidation of thick and thin magnesium films in an oxygen atmosphere at 3 × 10-a torr. Temperature was gradually 18g