Classified abstracts 470-552 Classified abstracts 470-479
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The label immediately following the title of each item denotes country or origin of publication, that at the end of each abstract indicates country of origin of work (where known).
I. General vacuum science and engineering 16. GASES AND SOLIDS
16 470. Adsorption of hydrogen and oxygen on (111) face of single crystal germanium. (USSR) The direct flash-filament method in a time-of-flight mass spectrometer was used to investigate the adsorption of hydrogen and oxygen on the (111) face of single crystal germanium at residual pressure of 5 x 10m9 torr. It is found that hydrogen is adsorbed on germanium only in presence of a hot tungsten filament. When the filament temperature changes, the amount of adsorbed hydrogen increases with the probability of hydrogen atomization on tungsten. The activation energy of hydrogen desorption was found to be 0.8 f 0.1 eV and the sticking coefficient is 10-l. The temperature dependence of the sticking coefficient of hydrogen on germanium is given. Oxygen is desorbed from germanium surface as oxides, GeG, with activation energy of 2.8 f 0.5 eV. On successive adsorption of hydrogen and oxyg& the desorption of Hz0 is observed. _ Yu I Belyakov and T N Kompaniets, Zh Tekh Fiz, 42 (4), April 1972, 855-860 (in Rum&). 18. GASEOUS ELECTRONICS 18 471. Imp&e electrical conductivity of an oxide cathode. (USSR) The temperature dependence of impulse electrical conductivity of (Ba,Sr,Ca) oxide, lo-* cm thick, was measured at various electric field strengths. It is found that the theory of porous conductivity of oxide cathode agrees with the obtained experimental data. V N Dudkin et al, Radiotekh Elektron, 17 (3), March 1972, 652-654 (in Russian). 18 472. Inthtence of p&nary unrent magnitude on some eharacteristlcs of Maiter emission of magnesimn 5uoride 5Ims. (USSR) The processes of formation and decay of Malter electron emission in vacuum. for MRF, films at current densities of 10T3 to 10-i A/cm2, are investigated: Experimental results are discussed. L A Serebrov and V L Shmulevich, Radiotekh Elektron, 17 (l), Jan 1972, 202-205 (in Russian). 18 473. Emission properties of caeshun 5hns on VR-27 alloy. (USSR) Using the methods of thermionic and field emissions, the electron emission of film systems VR-27-Q W-Cs and Re-Cs is investigated. It is found that the svstem VR-27-0 is more efficient than The system WCs. N D Konovalov and V A Kuznetsov, Radiotekh Elektron, 17 (l), Jan 1972, 2 16 (in Russian). 18 474. Stable semiconductor field cathode. (USSR) Stability of field electron emission from p-type Si and Ge and highohmic samples of n-Ge has been investigated. It is found that at certain values of field current the field electron emission only weakly depends on residual gas pressure and time. The pressure of residual gas was varied from 1 x lo+’ to 1 x 10m5 torr. At stable operation of the field cathode the density of the emitted current reached 10Z A/cm2 for p-Si and lo4 A/cm2 for n-Si. G N Fnrsey and N V Egorov, Zh Tekh Fit, 42 (5), May 1972, 10901092 (in Russian).
and
18 475. Inve&igatIou of mechanical strength of 5hn chromium field emitters. (USSR) Mechanical strength of film chromium field emitters is investigated utilizing the sparking which appear on loading the emitters with inverse electric fields prohibiting field emission. It is shown that the value of the destroying stress can reach 220 kg/mm2 for film chromium field emitters. B V Bondam& and V A Kumetsov, Zh Tekh Fir, 42 (5), May 1972, 1093-1095 (in Russian). 18 476. Measurement of potential distribution in the space charge layer by the method of non-disturbing probe. (USSR) The method is based on the absence of the disturbing action of a metallic probe with potential equal to the space potential. Using such probe, potential distribution in the space charge layer is measured in a helium discharge at pressure of 5 x 10-l torr. L Yu Abramovich and V A Comzin, Zh Tekh Fiz, 42 (5), May 1972, 1035-1038 (in Russian). 18 477. Escitation of an electron-cyclotron wave by a modulated helical electron beam. (USSR) The interaction between a helical, transverse speed-modulated electron beam and a plasma is investigated in a discharge chamber with base pressure of 2 x 1O-6 torr. Pulsed gas admission to low4 torr was used. It is shown that the modulated helical electron beam efficiently excites electron-cyclotron waves at the modulation frequency. V A Bashko et al, Zh Eksper Teor Fiz, 62 (S), May 1972, 1717-1720 (in Russian). 18 478. Iovestigation of angular and energy distribution of electrons released dmiog photoionization of atoms and molecuks. (USSR) An electron spectrometer is described which can be used to investigate the angular and energy spectra of electrons ejected during hotoionization of atoms and molecules by radiation of He (584 8: ) and Ne (736 and 744 A) resonance lines. The photoelectron spectrometer consists of three parts: working chamber, source of vacuum ultraviolet radiation and the system of photoelectron detection. The steel working chamber has inner double-walled magnetic shield of sheet permalloy. The chamber is evacuated by a 180 litre/sec mercury diffusion pump. Residual pressure in the chamber is low6 torr when operating the light source. The investigated gas is admitted to pressure of 5 x 10m5 to 5 x lo-& torr. Photoelectrons are analyzed in a movable telescope tube with plane retarding field grids and an electron multiplier. Plowing helium or neon lamp with pressure of 0.1 to 0.2 torr with differential pumping is used. The apparatus enables one to perform analogous investigation of photoelectrons ejected from solids. V B Milyaev and F I Vilesov, Prib Tekh Eksper, No 2, March-April 1972, 201-203 (in Russian) 18 479. The connection of esoelectroo emission with the processes of recovery and recrystallization. (Germany) The interdependence between exoelectron emission and the annealing processes of deformed Cu-Al alloys is investigated in vacuum of 10s5 torr. Experimental results are discussed. (USSR) R I Mints et al, Phys Stat Sol (a), 11 (l), Muy 1972, K29-K33.