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720. Compression piston gauge
Classified
abstracts
713-722
and niobium, prepared by zone melting. The measurements were carried out in sealed devices of quasi-spherical capacitor type with an antidynatron grid, at a residual gas pressure of 5x IO-” torr. The samples were mechanically polished, chemically and electrolytically etched and cleaned by prolonged heating at 1900 to 2000°C in vacu~~n~. It is found that ordering of the crystal lattice influences all basic secondary emission characteristics. Causes of the fine structure of measured secondary emission characteristics are discussed. A R Shulman et al. /ZI, AN SSSR Seu Fiz, 35 (2), 1971, 218-224 (i/r Ri/.\siu/r). 18 713. Secondary emission properties of oxide layers on the surface of activated alloys containing Li and Mg. (USSR) Results of an experimental investigation of the secondary emission properties of aluminium alloys containing Li and Mg are reported. The various activation regimes were studied on a continuously pumped vacuum system, and the basic secondary emission properties were investigated in sealed devices at a residual gas pressure of I IO-” torr. An increase of pressure to IOeR torr did not markedly influence the properties of the emitters. The highest coefficient of secondary electron emission, of the order of 30, was exhibited by alloys containing 0.05 to 0.15 per cent of Li and 0.5 to 1 per cent of M.g and activated at sufficiently high temperature (600 to 64O’C). It is assumed that MgO in the complex oxide system on the surface of activated Al-Li-Mg alloy plays a basic role in the enhancement of the secondary emission yield. The role of lithium is assumed to be in reducing the electron affinity due to formation of a thin, nearly monomolecular, lithium oxide film on the surface of MgO layers and grains. G V Stchinskiy, Izl; AN SSSR Ser Fiz, 35 (2), 1971, 237-241 (01 R/r.sXiu/r). I8 714. Field enhanced secondary emission of new low-voltage efficient emitters of porous layers of dielectrics. (USSR) The effect of thickness on the field enhanced transmission secondary electron emission are investigated for porous alkali halide emitters. Using CsI porous layers, low-voltage efficient emitters were prepared with transmission electron emission threshold at I keV and secondary electron emission coefficient of I5 to 45 at primary electron energy of 3 kcV. The porous dielectric layers were prepared by evaporation of salts in inert gas (in nitrogen at a pressure of the order of few tens of torr, and in argon at 2 to 4 torr). Inertia-less field enhanced secondary electron emission was observed for all emitters. The energy distribution of electrons emitted during transmission secondary emission is measured for the Csl layers. The surface potential of KCI layers is measured using an electron-beam voltmeter. The formation of inertial and inertia-less components of the secondary emission is observed in KCI and LiF layers. A P Balashova et al, Izv AN SSSR Srr Fiz, 35 (2), 1Y7 1, 242-247 (in R//.wiU/!). 18 715. Conductivity on the surface of grains in porous semiconducting oxides. (USSR) Results are presented of investigations on electrical conductivity, thermoelectromotive force, thermal conductivity and thermionic emission of porous barium-strontium-calcium oxides and single crystals of barium, strontium and calcium oxides in vacuum and in atmosphere of barium, caesium and magnesium vapours. An experimental device for investigating the influence of barium, caesium and magnesium vapours on these oxides is described. The experimental data confirm the hypothesis that in porous barium-strontiumcalcium oxides at low temperatures, when the role of electron gas in pores is not important, a basic conductivity is formed on the surface of the grains. It is shown that the observed phenomena cannot be explained by conductivity in the surface zone. It is supposed that the electrical conductivity is not caused by free surface electrons but that it arises as a result of phonon induced transitions of electrons from filled to unoccupied localized surface donor states, ie surface impurity conductivity predominantly by S- and S’centrcs takes place. N N Kovalev et al, F/z Twtd T&I, 13 (8). 1971, 2364-2370 (in R~ssicm). I8 :30 716. Photo-field emission from thin cadmium sulphide films on tungsten. (Germany) f+uperimcntal results of inbsestigation of photo-field emission from 242
thin cadmium sulphidc films. vacuum evaporated on tungsten are considered. (USSR) R M Khatapova and I L Sokolskaya, P/I.I,sStat Sol (a), 8 (I), NOV 1971, K51LK53.
II.
Vacuum
22. PUMPS
apparatus
and auxiliaries
AND PUMP FLUIDS
22 717. Partial pressure analyses by means of a quadrupole residual gas (Germany) analyzer and computer programme. A computer programme is presented for evaluating residual gas composition and total pressure in vacuum systems. The residual gas spectrum was determined by quadrupole residual gas analyzer and the nitrogen equivalent total pressure by hot cathode ionization gauge. For the data evaluation the computer programme SGAP was developed. Determination of the “cracking pattern” and the “sensitivity” is described and the structure of the programme explained. The reliability of the method and the magnitude of errors in the residual gas composition are demonstrated by a number of examples. R Dobrozemsky and W Farber, Vakuum-Techtrik, 20 (S), Dee 1971, 23 I-239 (in Gevma/r). 22 718. Development of a standard apparatus for measurement of total and partial pressures in the regions of high and ultrahigh vacuum. (USSR) The standard apparatus, with a base pressure of 3 .d IO-” Pa, consists of a preliminary pumping system, a cryogenic aggregate, and IOOlitre working volume. The preliminary pumping system contains a forevacuum pump filled with high-vacuum oil, valves, forevacuum forevacuum gauges, oil diffusion trap cooled by liquid nitrogen, pumps and a sorption trap. The preliminary pumping system is connected to the cryogenic aggregate by means of a bakeable highvacuum valve. The cryogenic aggregate contains a needle valve, condensation pumps and ultrahigh vacuum gauges, and is connected to the working chamber by means of a bakeable ultrahigh-vacuum valve. The working chamber contains a condensation pump, a needle valve, ultrahigh vacuum gauges and an omegatron partial pressure analyzer. The standard vacuum apparatus provides unity of pressure in the region of 10e3 to IO-” Pa of absolute total pressure and in the range of IO-” to IO-” Pa of partial pressure. M A Gulyaev and A V Eryukhin, Izmerir Tekh, No I I, 1971, 29-33 (i/r Russicm). 22 719. Liquid multi-impulse micromanometer. (USSR) A battery micromanometer is described, in which the collector and the measuring capillaries are made as a unit. Booster oil is used as working liquid. The measuring tubes can be inclined at an arbitrary angle. The described battery micromanometer with an absolute error of ho.44 Pa was employed for investigating gas dynamic processes in a model of vacuum equipment for refining of tin. The absolute pressure was determined with the aid of a McLeod gauge. A 1 Chernogolov et al, Izmevit Tekh, No 8, 1971, 88-89 (i/r Ru~ian). 22 720. Compression piston gauge. (USSR) Construction of a piston gauge is described, which is based on rarefaction and compression of the measured gas. The gauge permits measurement of absolute pressures below atmospheric down to 2.66 Pa with an error not greater than 0.5 per cent. It can be used as portable standard gauge and does not require a pumping system. G I Polukhin and V A Ryzhov, Izmerif Tekh, No 8, 197 I, 89-W (it/ Russiu,r). 22 (USSR) 721. Composite gauge for measurement of absolute pressures. An absolute mercury gauge with digital indication is described and examined. In the collector, a pressure below I .33 Pa is maintained by a forevacuum pump and monitored by a thermocouple gauge. Six Utube manometers are connected to the collector. The mercury level in 8 mm manometric tubes is measured with the aid of steel balls floating on the mercury level and movable differential transformers. S A Safronnikov, Jzmcrit Tckh, No 9, I97 I , IO1 I02 (in R~~wiun). 22 722, Utilization of vacuum contact-less thermal converters for measurement of pressure. (USSR) Experiments carried out haue shown that the contact-lcs\ thermo-
abstracts
713-722
and niobium, prepared by zone melting. The measurements were carried out in sealed devices of quasi-spherical capacitor type with an antidynatron grid, at a residual gas pressure of 5x IO-” torr. The samples were mechanically polished, chemically and electrolytically etched and cleaned by prolonged heating at 1900 to 2000°C in vacu~~n~. It is found that ordering of the crystal lattice influences all basic secondary emission characteristics. Causes of the fine structure of measured secondary emission characteristics are discussed. A R Shulman et al. /ZI, AN SSSR Seu Fiz, 35 (2), 1971, 218-224 (i/r Ri/.\siu/r). 18 713. Secondary emission properties of oxide layers on the surface of activated alloys containing Li and Mg. (USSR) Results of an experimental investigation of the secondary emission properties of aluminium alloys containing Li and Mg are reported. The various activation regimes were studied on a continuously pumped vacuum system, and the basic secondary emission properties were investigated in sealed devices at a residual gas pressure of I IO-” torr. An increase of pressure to IOeR torr did not markedly influence the properties of the emitters. The highest coefficient of secondary electron emission, of the order of 30, was exhibited by alloys containing 0.05 to 0.15 per cent of Li and 0.5 to 1 per cent of M.g and activated at sufficiently high temperature (600 to 64O’C). It is assumed that MgO in the complex oxide system on the surface of activated Al-Li-Mg alloy plays a basic role in the enhancement of the secondary emission yield. The role of lithium is assumed to be in reducing the electron affinity due to formation of a thin, nearly monomolecular, lithium oxide film on the surface of MgO layers and grains. G V Stchinskiy, Izl; AN SSSR Ser Fiz, 35 (2), 1971, 237-241 (01 R/r.sXiu/r). I8 714. Field enhanced secondary emission of new low-voltage efficient emitters of porous layers of dielectrics. (USSR) The effect of thickness on the field enhanced transmission secondary electron emission are investigated for porous alkali halide emitters. Using CsI porous layers, low-voltage efficient emitters were prepared with transmission electron emission threshold at I keV and secondary electron emission coefficient of I5 to 45 at primary electron energy of 3 kcV. The porous dielectric layers were prepared by evaporation of salts in inert gas (in nitrogen at a pressure of the order of few tens of torr, and in argon at 2 to 4 torr). Inertia-less field enhanced secondary electron emission was observed for all emitters. The energy distribution of electrons emitted during transmission secondary emission is measured for the Csl layers. The surface potential of KCI layers is measured using an electron-beam voltmeter. The formation of inertial and inertia-less components of the secondary emission is observed in KCI and LiF layers. A P Balashova et al, Izv AN SSSR Srr Fiz, 35 (2), 1Y7 1, 242-247 (in R//.wiU/!). 18 715. Conductivity on the surface of grains in porous semiconducting oxides. (USSR) Results are presented of investigations on electrical conductivity, thermoelectromotive force, thermal conductivity and thermionic emission of porous barium-strontium-calcium oxides and single crystals of barium, strontium and calcium oxides in vacuum and in atmosphere of barium, caesium and magnesium vapours. An experimental device for investigating the influence of barium, caesium and magnesium vapours on these oxides is described. The experimental data confirm the hypothesis that in porous barium-strontiumcalcium oxides at low temperatures, when the role of electron gas in pores is not important, a basic conductivity is formed on the surface of the grains. It is shown that the observed phenomena cannot be explained by conductivity in the surface zone. It is supposed that the electrical conductivity is not caused by free surface electrons but that it arises as a result of phonon induced transitions of electrons from filled to unoccupied localized surface donor states, ie surface impurity conductivity predominantly by S- and S’centrcs takes place. N N Kovalev et al, F/z Twtd T&I, 13 (8). 1971, 2364-2370 (in R~ssicm). I8 :30 716. Photo-field emission from thin cadmium sulphide films on tungsten. (Germany) f+uperimcntal results of inbsestigation of photo-field emission from 242
thin cadmium sulphidc films. vacuum evaporated on tungsten are considered. (USSR) R M Khatapova and I L Sokolskaya, P/I.I,sStat Sol (a), 8 (I), NOV 1971, K51LK53.
II.
Vacuum
22. PUMPS
apparatus
and auxiliaries
AND PUMP FLUIDS
22 717. Partial pressure analyses by means of a quadrupole residual gas (Germany) analyzer and computer programme. A computer programme is presented for evaluating residual gas composition and total pressure in vacuum systems. The residual gas spectrum was determined by quadrupole residual gas analyzer and the nitrogen equivalent total pressure by hot cathode ionization gauge. For the data evaluation the computer programme SGAP was developed. Determination of the “cracking pattern” and the “sensitivity” is described and the structure of the programme explained. The reliability of the method and the magnitude of errors in the residual gas composition are demonstrated by a number of examples. R Dobrozemsky and W Farber, Vakuum-Techtrik, 20 (S), Dee 1971, 23 I-239 (in Gevma/r). 22 718. Development of a standard apparatus for measurement of total and partial pressures in the regions of high and ultrahigh vacuum. (USSR) The standard apparatus, with a base pressure of 3 .d IO-” Pa, consists of a preliminary pumping system, a cryogenic aggregate, and IOOlitre working volume. The preliminary pumping system contains a forevacuum pump filled with high-vacuum oil, valves, forevacuum forevacuum gauges, oil diffusion trap cooled by liquid nitrogen, pumps and a sorption trap. The preliminary pumping system is connected to the cryogenic aggregate by means of a bakeable highvacuum valve. The cryogenic aggregate contains a needle valve, condensation pumps and ultrahigh vacuum gauges, and is connected to the working chamber by means of a bakeable ultrahigh-vacuum valve. The working chamber contains a condensation pump, a needle valve, ultrahigh vacuum gauges and an omegatron partial pressure analyzer. The standard vacuum apparatus provides unity of pressure in the region of 10e3 to IO-” Pa of absolute total pressure and in the range of IO-” to IO-” Pa of partial pressure. M A Gulyaev and A V Eryukhin, Izmerir Tekh, No I I, 1971, 29-33 (i/r Russicm). 22 719. Liquid multi-impulse micromanometer. (USSR) A battery micromanometer is described, in which the collector and the measuring capillaries are made as a unit. Booster oil is used as working liquid. The measuring tubes can be inclined at an arbitrary angle. The described battery micromanometer with an absolute error of ho.44 Pa was employed for investigating gas dynamic processes in a model of vacuum equipment for refining of tin. The absolute pressure was determined with the aid of a McLeod gauge. A 1 Chernogolov et al, Izmevit Tekh, No 8, 1971, 88-89 (i/r Ru~ian). 22 720. Compression piston gauge. (USSR) Construction of a piston gauge is described, which is based on rarefaction and compression of the measured gas. The gauge permits measurement of absolute pressures below atmospheric down to 2.66 Pa with an error not greater than 0.5 per cent. It can be used as portable standard gauge and does not require a pumping system. G I Polukhin and V A Ryzhov, Izmerif Tekh, No 8, 197 I, 89-W (it/ Russiu,r). 22 (USSR) 721. Composite gauge for measurement of absolute pressures. An absolute mercury gauge with digital indication is described and examined. In the collector, a pressure below I .33 Pa is maintained by a forevacuum pump and monitored by a thermocouple gauge. Six Utube manometers are connected to the collector. The mercury level in 8 mm manometric tubes is measured with the aid of steel balls floating on the mercury level and movable differential transformers. S A Safronnikov, Jzmcrit Tckh, No 9, I97 I , IO1 I02 (in R~~wiun). 22 722, Utilization of vacuum contact-less thermal converters for measurement of pressure. (USSR) Experiments carried out haue shown that the contact-lcs\ thermo-