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Omegatron investigation of hydrogen in an ultra-high vacuum system
396
Classified Abstracts 982--986
pressure in the various types of valves has been followed after pumping, during screening etc. Whether these curves can explain all different behaviours of the investigated valves, will be discussed. (Germany) (Authors) F. H. R. Almer, et al., 2nd Internat. Symp. residual gases in electron tubes, Milan, (March 1963), Nuovo Cimento (in press). 47 : 31 : 33 982. The influence of the gas ambient on the emission properties of oxide coated cathodes in receiving valves. (Italy) The emission properties of oxide coated cathodes in receiving valves are shown to be strongly influenced by the partial pressures of the residual gases. Different getter pumping speeds for different gases can therefore have a strong influence on the activation of the oxide coated cathode. The gas analyses were made by means of an omegatron and simultaneously emission and noise measurements were performed. The use of new getters with even higher pumping speed for a particular gas than that of barium getters may result in poorly activated cathodes, if no precautions are taken. In c o n c l u s i o n the demands on getter performance in valves will be discussed. (Germany) (Author) S. Garbe, 2nd Internat. Symp. residual gases in electron tubes, Milan, (March 1963), Nuovo Cimento (in press).
4_.7: . ~ 983. The influence of barium and magnesium getters on the activation of mixed alkaline earth oxide coated cathodes. (Italy) A planar diode of simple construction and having minimum amount of extraneous material has been used to investigate the influence of getters on the activation of mixed alkaline earth oxide coated cathodes. The results show that cathodes can be permanently activated to a higher level of emission by evaporating barium onto a cold cathode and that magnesium can be used in the same way to increase the initial rate of activation. The results also support Nergaard's (1959) view that the cathode reacts with everything in the tube through the gas phase, so that even when getters are used in the conventional way their influence on the cathode cannot be ignored. (Great Britain) (Authors) R. K. Fitch and M. A. Young, 2nd Internat. Symp. residual gases in electron tubes, Milan, (March 1963), Nuovo Cimento (in press). 47 : 22 : 41 984. Residual gas pressure in 200 W-CW magnetron made of commercial E copper of 99.90 purity (continuous vertical cast).
(Italy) The paper describes the pumping process of 200 W-CW magnetrons made of E copper 99.90 per cent, unusual for the production of magnetrons. Residual gas pressure was measured by tetrode and Bayard Alpert ionization gauges sealed to mag-
netrons. The pressure was measured at the different working conditions of magnetron. It was stated that after correct vacuum treatment the pressure of residual gases did not exceed 4 × 10 -~ tort. We have made several magnetrons, applying the described technology, which have more than 1000 operating hours without any of the troubles that may originate in a bad vacuum. (Czechoslovakia) (Authors) A. Belie, et al., 2nd Internat. Symp. residual gases in electron tubes, Milan, (March 1963), Nuovo Cimento (in press). 47 : 19 985. Influence of residual gas pressure on dark currents in photomultiplier tubes. (Italy) Leakage currents, thermionic emission of the cathode and the first multiplying stages, field emission, light feedback and ion currents caused by the ionization of residual gases are the main sources of dark currents Id in photomultiplier tubes. The problem treated in this paper is the influence of residual gas pressure on tube performances. A sealed off system composed of a photomultiplier tube F M 50 and an Alpert gauge was designed. Gas pressure changes in the 10-3 to 10-a° torr range as well as simultaneous multiplier performances could be determined in this experimental system. The contribution of particular dark current sources to ld had been established. The variation of Id at various pressures was measured for different multiplier .operating conditions and the part of ld caused by ionization of cesium vapour was estimated. (Czechoslovakia) (Authors) E. Kansky and B. Otrin, 2nd Internat. Symp. residual gases in electron tubes, Milan, (March 1963), Nuovo Cimento (in press). 47 : 16 : 22 Omegatron investigation of hydrogen in an ultra-high vacuum system. See Abstr. No. 893. Getter flashing with electrodes bombarding.
47:11:33 See Abstr. No. 882.
Volume and surface effects on metal outgassing. 881.
47 : 11 : 36 See Abstr. No.
47 : 22 : 33 The omegatron versus a sector-type mass spectrometer for residual gas studies. See Abstr. No. 918.
49.
M i s c e l l a n e o u s M a t e r i a l s and T e c h n i q u e s
49 986. Gaseous diffusion in porous media. III. Thermal transpiration. (U.S.A.) E. A. Mason, J. Chem. Phys., 38 (8), 15 April 1963, 1808-1826.
Classified Abstracts 982--986
pressure in the various types of valves has been followed after pumping, during screening etc. Whether these curves can explain all different behaviours of the investigated valves, will be discussed. (Germany) (Authors) F. H. R. Almer, et al., 2nd Internat. Symp. residual gases in electron tubes, Milan, (March 1963), Nuovo Cimento (in press). 47 : 31 : 33 982. The influence of the gas ambient on the emission properties of oxide coated cathodes in receiving valves. (Italy) The emission properties of oxide coated cathodes in receiving valves are shown to be strongly influenced by the partial pressures of the residual gases. Different getter pumping speeds for different gases can therefore have a strong influence on the activation of the oxide coated cathode. The gas analyses were made by means of an omegatron and simultaneously emission and noise measurements were performed. The use of new getters with even higher pumping speed for a particular gas than that of barium getters may result in poorly activated cathodes, if no precautions are taken. In c o n c l u s i o n the demands on getter performance in valves will be discussed. (Germany) (Author) S. Garbe, 2nd Internat. Symp. residual gases in electron tubes, Milan, (March 1963), Nuovo Cimento (in press).
4_.7: . ~ 983. The influence of barium and magnesium getters on the activation of mixed alkaline earth oxide coated cathodes. (Italy) A planar diode of simple construction and having minimum amount of extraneous material has been used to investigate the influence of getters on the activation of mixed alkaline earth oxide coated cathodes. The results show that cathodes can be permanently activated to a higher level of emission by evaporating barium onto a cold cathode and that magnesium can be used in the same way to increase the initial rate of activation. The results also support Nergaard's (1959) view that the cathode reacts with everything in the tube through the gas phase, so that even when getters are used in the conventional way their influence on the cathode cannot be ignored. (Great Britain) (Authors) R. K. Fitch and M. A. Young, 2nd Internat. Symp. residual gases in electron tubes, Milan, (March 1963), Nuovo Cimento (in press). 47 : 22 : 41 984. Residual gas pressure in 200 W-CW magnetron made of commercial E copper of 99.90 purity (continuous vertical cast).
(Italy) The paper describes the pumping process of 200 W-CW magnetrons made of E copper 99.90 per cent, unusual for the production of magnetrons. Residual gas pressure was measured by tetrode and Bayard Alpert ionization gauges sealed to mag-
netrons. The pressure was measured at the different working conditions of magnetron. It was stated that after correct vacuum treatment the pressure of residual gases did not exceed 4 × 10 -~ tort. We have made several magnetrons, applying the described technology, which have more than 1000 operating hours without any of the troubles that may originate in a bad vacuum. (Czechoslovakia) (Authors) A. Belie, et al., 2nd Internat. Symp. residual gases in electron tubes, Milan, (March 1963), Nuovo Cimento (in press). 47 : 19 985. Influence of residual gas pressure on dark currents in photomultiplier tubes. (Italy) Leakage currents, thermionic emission of the cathode and the first multiplying stages, field emission, light feedback and ion currents caused by the ionization of residual gases are the main sources of dark currents Id in photomultiplier tubes. The problem treated in this paper is the influence of residual gas pressure on tube performances. A sealed off system composed of a photomultiplier tube F M 50 and an Alpert gauge was designed. Gas pressure changes in the 10-3 to 10-a° torr range as well as simultaneous multiplier performances could be determined in this experimental system. The contribution of particular dark current sources to ld had been established. The variation of Id at various pressures was measured for different multiplier .operating conditions and the part of ld caused by ionization of cesium vapour was estimated. (Czechoslovakia) (Authors) E. Kansky and B. Otrin, 2nd Internat. Symp. residual gases in electron tubes, Milan, (March 1963), Nuovo Cimento (in press). 47 : 16 : 22 Omegatron investigation of hydrogen in an ultra-high vacuum system. See Abstr. No. 893. Getter flashing with electrodes bombarding.
47:11:33 See Abstr. No. 882.
Volume and surface effects on metal outgassing. 881.
47 : 11 : 36 See Abstr. No.
47 : 22 : 33 The omegatron versus a sector-type mass spectrometer for residual gas studies. See Abstr. No. 918.
49.
M i s c e l l a n e o u s M a t e r i a l s and T e c h n i q u e s
49 986. Gaseous diffusion in porous media. III. Thermal transpiration. (U.S.A.) E. A. Mason, J. Chem. Phys., 38 (8), 15 April 1963, 1808-1826.