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Vacuum lock-sample changer for a mass spectrometer
Classified
abstracts
1908-l
918
1000 I./set four-section mounting of magnets with rcclangulal magnetic conductors is presented. For magnetic-discharge pumps with pumping speed below 800 I./XC two-section, mulli-layer mounting of magnets with working gaps belwecn them is advantageous. Vacuum characlcristics of pumps with lower weight arc presented. E I Kontor and M S Galicv, fro/~/ oj’ A/wr Sci ctttrl Tedtttol, Ser P/t.~:v attd Techto/ of High Vactrttttt. Cdl, No I, Kharkov 1973, 30-32
(in Rtrssiatt). 21 1908. On choice of optimum operation conditions of a diffusion pump system at pumping of hydrogen. (USSR) An optimized scheme of a pumping system. consisting of cryogenic and diffusion ptmips for attaining pressures lower than IO-‘” Torr. is presented. To lower the level of hydrogen concentration, which appears to be the main residual gas in baked vacuum syslcms, a scheme with dilTusion ptmips connected in series is recommended. Use of two or more ditfusion pumps is recommended. To obtain optimum conditions of pumping, it is necessary to select suitable operating conditions for each of dill’usion pumps and in sonic cases also to choose suitable pumps. A method and results of examination of three diffusion pumps connected in series are presented. The influence of backing pressure on the pumping speed for hydrogen is shown. The backing pressure should be lower than 6 ,’ lO-2 Torr for stable operation of diffusion pumps at pumping of hydrogen. S F Grishin et 31, Probl of Alotttic Sciettce attcl Techtol, Ser Plt~~sattd Tecltttol of High Vacttttttt, Co/l, No I. Kharkov 1973. 48-50 (itt
Rttssiatt).
22. GAUGES
AND
MEASUREMENT
OF
LOW
PRESSURES
22 1909. The retardation system and collision chamber of a tandem mass spectrometer. (Roumania) Design of a tandem mass spectrometer, intended for the investigation of ion-molecular reactions at low energies of 0.2 to 100 eV, is described. The retardation system consists of an electrostatic lens and two slits. Injection of the ion beam into the collision chamber is performed with the aid of a copper capillary, enabling to maintain a pressure of 10e5 Torr in the mass spectrometer chamber. The apparatus was examined with N,+ and Hz+ ions. P Ardelean et al, Ret Rotrttt Pltys, 19 (I ), 1974, 49-54. 22 1910. On sensitivity of the correlation mass spectrometer. (Bulgaria) T’he sensitivity of the correlation mass spectrometer for residual gases in vacuum systems is considered. The signal to noise ratio on the output of measuring instrument is determined. It is shown that the sensitivity of the correlation mass spectrometer depends on Fluctuations of amplification and bandwidth of amplifiers. M Mikhalev, Rep of Elecwott 1tt.u of Bulg Acad of Sciettce, No 7,
1974, 83-9 1 (in Bttlgariatt). 22 1911. The influence of the compensating potential on the level of secondary harmonic peaks in a high-frequency mass analyser. :Czechoslovakia) The influence of the compensating potential on the level of harnonic peaks of a mass spectrum in a high-frequency analyser of :he Bennet type is investigated. The value of the compensating ,otential is determined for which the linearity of the analyser is >rovided. L Cervenan, Acta Fat Rertrrtt Nattrr Utth Cottte~t Pltys, No 13, 1973, 2-17 (in Slooak). 22 1912. Orbitron type ionization vacuometer. (Bulgaria) The ion-current characteristics of a pressure sensor of the Orbitron :ype are investigated in the pressure range of IOe4 to 1Oes Torr. :t is found that the ion current strongly depends on the electric field :onfiguration around the emitter. A presence of a space charge is bund around the emitter and its influence is studied. k’u Simeonova et al, Izu Inst Elektron BQ AN, No 7, 1974, 49-55
in Bulgarian).
23. PLUMBING,
VACUUM
VALVES,
BAFFLES
AND
TRAPS
-.-. LJ 1913. An automatic throttling valve for mechanical vacuum pumps. (USSR) Design of an automatic throttling valve for mechanical vacuum pumps is dcscribcd. The valve maintains a stable pressure of 40 Torr at the entrance of mechanical ptmlps during the period of their switching on. Two bellows are used to drive a throttling valve opening. The automatic throttling valve can also be used for protection of the mechanical vacuum pump in the case of rapid pressure increase. S F Kravchenko et al, Probl of Aiotttic Sciettce attrl Tecltttol, Ser Pltys attrl Tecltttol of High Vocltrojr. C’oll, No I, Kharkov 1973, 14-l 5
(itt Rttssiatt). 23 1914. To the problem of throttling of gas flow at the evacuation of a vacuum equipment by mechanical pumps. (USSR) Basic features of the design of a throttling valve, which could maintain a constant pressure at the entrance of a mechanical vacuum pump during its switching on, are theoretically considered. The dependence of the throttling opening on pressure changes in the evacuated volume is obtained. B V Borts, Probl o/ Aiotttic Science ad Tecltnol, Ser Pltys and Tecltrtol of High Vacrtttttt, Coil, NO I, Kharkov 1973, IO-13 (itt Rttssiatt). 23 1915. Vacuum lock-sample changer for a mass spectrometer. (GB) A sequentially operating vacuum lock-sample changer for use with a thermal ionization source mass spectrometer has been designed and fabricated. Insertion or removal of sample filaments, preconditioning of the sample and analysis can be carried out simultaneously, saving considerably on the total time of analysis per sample. It has been in continuous operation for a period of more than two years without any servicing. (India) B S Prahallada Rao and S R Halbe, J Pltys E: Sri Ittstrrtttt, 9, (3) 1976.205-207.
III.
Vacuum
30. EVAPORATION
applications AND
DEPOSITION
IN
VACUO
30 1916. Transmission, energy distribution, and secondary electron excitation of fast electrons in thin solid films. (Germany) The thin film method was used to investigate the relation between transmission, backscattering, energy distribution, and secondary electron excitation of fast electrons by inelastic scattering in solids. A three-collector system was used for measurement of the transmission and backscattering of electrons with energy between 0.5 and 4 keV in free thin films of Be, Al, Ge, Cu and Ag in a vacuum of 5 s IO- * Torr. A retarding potential of -50 V was used to separate slow secondary electrons from scattered primary electrons. The energy distribution of transmitted electrons was investigated with the aid of a retarding field analyzer. It is found that the secondary electron efficiency of emerging electrons is 3 to 15 times larger than that of incident electrons. From this fact it may be concluded that there is an anisotropy of the secondary electron generation function in such a manner that the forward production is considerably greater than the production backwards. H J Fitting, Phys Sfaf Sol (a), 26(2), 1974, 525-535. 30 1917. The amorphous-crystalline transition in germanium films. (Germany) The amorphous-crystalline structure transition in vacuum deposited germanium films is investigated in terms of change in electrical conductivity..The germanium films have been prepared at a deposition rate of 100 nm/min by electron-beam evaporation on polyimide, mica, glass, alumina and sapphire substrates at a pressure of IOb6 Torr. The transition is observed at 235”C, and it appears as an abrupt change in conductivity of four orders of magnitude. (Norway) J S Johannessen, P/~ys S/at Sol (a), 26(2), 1974,571-577. 30 1918. Kinetics of compound formation in thin film couples of Al and transition metals. (USA) Intermetallic compound formation at metal-metal interfaces was observed for thin film couples of Al and transition metals such as 355
abstracts
1908-l
918
1000 I./set four-section mounting of magnets with rcclangulal magnetic conductors is presented. For magnetic-discharge pumps with pumping speed below 800 I./XC two-section, mulli-layer mounting of magnets with working gaps belwecn them is advantageous. Vacuum characlcristics of pumps with lower weight arc presented. E I Kontor and M S Galicv, fro/~/ oj’ A/wr Sci ctttrl Tedtttol, Ser P/t.~:v attd Techto/ of High Vactrttttt. Cdl, No I, Kharkov 1973, 30-32
(in Rtrssiatt). 21 1908. On choice of optimum operation conditions of a diffusion pump system at pumping of hydrogen. (USSR) An optimized scheme of a pumping system. consisting of cryogenic and diffusion ptmips for attaining pressures lower than IO-‘” Torr. is presented. To lower the level of hydrogen concentration, which appears to be the main residual gas in baked vacuum syslcms, a scheme with dilTusion ptmips connected in series is recommended. Use of two or more ditfusion pumps is recommended. To obtain optimum conditions of pumping, it is necessary to select suitable operating conditions for each of dill’usion pumps and in sonic cases also to choose suitable pumps. A method and results of examination of three diffusion pumps connected in series are presented. The influence of backing pressure on the pumping speed for hydrogen is shown. The backing pressure should be lower than 6 ,’ lO-2 Torr for stable operation of diffusion pumps at pumping of hydrogen. S F Grishin et 31, Probl of Alotttic Sciettce attcl Techtol, Ser Plt~~sattd Tecltttol of High Vacttttttt, Co/l, No I. Kharkov 1973. 48-50 (itt
Rttssiatt).
22. GAUGES
AND
MEASUREMENT
OF
LOW
PRESSURES
22 1909. The retardation system and collision chamber of a tandem mass spectrometer. (Roumania) Design of a tandem mass spectrometer, intended for the investigation of ion-molecular reactions at low energies of 0.2 to 100 eV, is described. The retardation system consists of an electrostatic lens and two slits. Injection of the ion beam into the collision chamber is performed with the aid of a copper capillary, enabling to maintain a pressure of 10e5 Torr in the mass spectrometer chamber. The apparatus was examined with N,+ and Hz+ ions. P Ardelean et al, Ret Rotrttt Pltys, 19 (I ), 1974, 49-54. 22 1910. On sensitivity of the correlation mass spectrometer. (Bulgaria) T’he sensitivity of the correlation mass spectrometer for residual gases in vacuum systems is considered. The signal to noise ratio on the output of measuring instrument is determined. It is shown that the sensitivity of the correlation mass spectrometer depends on Fluctuations of amplification and bandwidth of amplifiers. M Mikhalev, Rep of Elecwott 1tt.u of Bulg Acad of Sciettce, No 7,
1974, 83-9 1 (in Bttlgariatt). 22 1911. The influence of the compensating potential on the level of secondary harmonic peaks in a high-frequency mass analyser. :Czechoslovakia) The influence of the compensating potential on the level of harnonic peaks of a mass spectrum in a high-frequency analyser of :he Bennet type is investigated. The value of the compensating ,otential is determined for which the linearity of the analyser is >rovided. L Cervenan, Acta Fat Rertrrtt Nattrr Utth Cottte~t Pltys, No 13, 1973, 2-17 (in Slooak). 22 1912. Orbitron type ionization vacuometer. (Bulgaria) The ion-current characteristics of a pressure sensor of the Orbitron :ype are investigated in the pressure range of IOe4 to 1Oes Torr. :t is found that the ion current strongly depends on the electric field :onfiguration around the emitter. A presence of a space charge is bund around the emitter and its influence is studied. k’u Simeonova et al, Izu Inst Elektron BQ AN, No 7, 1974, 49-55
in Bulgarian).
23. PLUMBING,
VACUUM
VALVES,
BAFFLES
AND
TRAPS
-.-. LJ 1913. An automatic throttling valve for mechanical vacuum pumps. (USSR) Design of an automatic throttling valve for mechanical vacuum pumps is dcscribcd. The valve maintains a stable pressure of 40 Torr at the entrance of mechanical ptmlps during the period of their switching on. Two bellows are used to drive a throttling valve opening. The automatic throttling valve can also be used for protection of the mechanical vacuum pump in the case of rapid pressure increase. S F Kravchenko et al, Probl of Aiotttic Sciettce attrl Tecltttol, Ser Pltys attrl Tecltttol of High Vocltrojr. C’oll, No I, Kharkov 1973, 14-l 5
(itt Rttssiatt). 23 1914. To the problem of throttling of gas flow at the evacuation of a vacuum equipment by mechanical pumps. (USSR) Basic features of the design of a throttling valve, which could maintain a constant pressure at the entrance of a mechanical vacuum pump during its switching on, are theoretically considered. The dependence of the throttling opening on pressure changes in the evacuated volume is obtained. B V Borts, Probl o/ Aiotttic Science ad Tecltnol, Ser Pltys and Tecltrtol of High Vacrtttttt, Coil, NO I, Kharkov 1973, IO-13 (itt Rttssiatt). 23 1915. Vacuum lock-sample changer for a mass spectrometer. (GB) A sequentially operating vacuum lock-sample changer for use with a thermal ionization source mass spectrometer has been designed and fabricated. Insertion or removal of sample filaments, preconditioning of the sample and analysis can be carried out simultaneously, saving considerably on the total time of analysis per sample. It has been in continuous operation for a period of more than two years without any servicing. (India) B S Prahallada Rao and S R Halbe, J Pltys E: Sri Ittstrrtttt, 9, (3) 1976.205-207.
III.
Vacuum
30. EVAPORATION
applications AND
DEPOSITION
IN
VACUO
30 1916. Transmission, energy distribution, and secondary electron excitation of fast electrons in thin solid films. (Germany) The thin film method was used to investigate the relation between transmission, backscattering, energy distribution, and secondary electron excitation of fast electrons by inelastic scattering in solids. A three-collector system was used for measurement of the transmission and backscattering of electrons with energy between 0.5 and 4 keV in free thin films of Be, Al, Ge, Cu and Ag in a vacuum of 5 s IO- * Torr. A retarding potential of -50 V was used to separate slow secondary electrons from scattered primary electrons. The energy distribution of transmitted electrons was investigated with the aid of a retarding field analyzer. It is found that the secondary electron efficiency of emerging electrons is 3 to 15 times larger than that of incident electrons. From this fact it may be concluded that there is an anisotropy of the secondary electron generation function in such a manner that the forward production is considerably greater than the production backwards. H J Fitting, Phys Sfaf Sol (a), 26(2), 1974, 525-535. 30 1917. The amorphous-crystalline transition in germanium films. (Germany) The amorphous-crystalline structure transition in vacuum deposited germanium films is investigated in terms of change in electrical conductivity..The germanium films have been prepared at a deposition rate of 100 nm/min by electron-beam evaporation on polyimide, mica, glass, alumina and sapphire substrates at a pressure of IOb6 Torr. The transition is observed at 235”C, and it appears as an abrupt change in conductivity of four orders of magnitude. (Norway) J S Johannessen, P/~ys S/at Sol (a), 26(2), 1974,571-577. 30 1918. Kinetics of compound formation in thin film couples of Al and transition metals. (USA) Intermetallic compound formation at metal-metal interfaces was observed for thin film couples of Al and transition metals such as 355