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1088. An investigation of the energy gain in Bennett's radio-frequency mass spectrometer
Classified abstracts 1088-1101 linearity of pressure and ion current over the range 10 ntorr to 1 mtorr. The gauge has a sensitivity of up to 5000 torr -1. It has been calibrated against a Bayard-Alpert ionization gauge using dry air. R K Fitch and W J Thatcher, J Sci Instruments, Ser 2, 1 (3), 1968, 317-319. 22 1088. An investigation of the energy gain in Bennett's radio-frequency mass spectrometer. (Great Britain) The results of an investigation of the energy gain of ions in 7-5 and 9-7 cycle rf mass spectrometers are presented. Graphical results were obtained by means of an analogue computer. The effect of the inaccuracy of adjustment of drift space lengths on the energy gain of the 7-5 cycle spectrometer was studied. Criteria from which the accuracy of the construction of an analyser may be estimated, are discussed. (Czechoslovakia). V Martisovits and S Szarka, J Sci Instrum, Ser 2, 1 (3), 1968, 326--328. 22 1089. Mass spectrometer with molecular ionization by strong electric field and electron impact. (USSR) An improvement in the design of the type MI-1301 sectorial mass spectrometer is described, which is based on a modification of the ionization chamber. With this arrangement, either field or electron impact ionization is possible. A resolution of 120 is obtained. I Z Korostyshevskiy and I V Gol'denfei'd, Pribory Tekh Eksper, 13 (1), Jan-Feb 1968, 146-148 (in Russian). 22 1090. Quantitative analysis by mass spectrometer with ion accumulation in oscillating packets. (USSR) Conventional mass spectrometry with ion accumulation Was improved by producing the accumulated ions in a series of oscillating packets. The linear dependence between the partial pressure and the massspectrometer output signal was satisfied for at least 250 packets per set at 10-e torr, and 25 packets at 10-5 torr. This means that the method allows quantitative analysis at pressures below 5 × 10-6 torr and only qualitative analysis at higher pressures. L N Linnik et al, Pribory Tekh Eksper, 13 (1), Jan-Feb 1968, 148-151
(in Russian). 22 1091. Chromatic aberrations of a mass spectrometer with a step homogeneous magnetic field. (USSR) Chromatic aberrations were measured in a two-step mass spectrometer with pi-radian focusing. The possibility is shown of the choice of parameters to reduce the first order chromatic aberrations to zero. V I Karataev, Pribory Tekh Eksper, 13 (1), Jan-Feb 1968, 152-153
(in Russian). 22 1092. Insertion of samples into a mass spectrometer in the form of a molecular beam. (USSR) A molecular beam source is described for inserting vapours of the sample into the mass spectrometer ionization chamber. Results of analysis on the MI-1305 mass spectrometer show a high signal-tonoise ratio. (Romania) G Alexandru, Pribory Tekh Eksper, 13 (1), Jan-Feb 1968, 154-155
(in Russian). 22 1093. Cold cathode magnetron vacuum gauge. (USSR) A new magnetron gauge is described in which the cold cathode has linear characteristics in the range of 10-xl to 10-3 torr when an anode voltage of 5.5 kV and magnetic field of 1100 Oe are employed. When the field is below 1080 Oe, the characteristics are non-linear below 10-9 torr. Sensitivity, for N=, of 2 A/torr and relative sensitivities of 0.4 for H= and 0.12 for He were determined by calibration with an MM-14 M inverted magnetron gauge and an MI-12-8 Bayard-Alpert gauge. The parasitic currents correspond to the pressure of 10-x2 tort. The gaugehead is baked by an external furnace at 450°C for 40 hours and then is operated for 5 hours at the normal regime to prevent errors caused by degassing of the gaugehead. G A Nichiperovieh and I F Khanina, Pribory Tekh Eksper, 13 (1), Jan-Feb 1968, 156-159 (in Russian). 22 1094. Mass spectrometer ion collector with movable slots. (USSR) The design of the ion collection chamber in the MI-1305 mass spectrometer is described. The slot is movable and simultaneously a V-shaped collector and antidynatron electrode are also moved. The
V-shape of the collector was chosen to minimize secondary emission since ions are not incident in the normal direction. V P Strizhov et al, Pribory Tekh Eksper, 13 (2), March-April 1968, 156-157 (in Russian).
22 1095. Measuring devices of high accuracy. (USSR) Designed at the VNIIK laboratories as a primary standard, the VP vacuum gauge is based on a rotating piston with oil-sealing and spring loading. The position of the piston is determined with an M I R type microscope. A n accuracy of ± 1.5 × 10-~ torr in the range 0 to 75 torr was obtained. Anon, lzmcrit Tekh, no 4, 1968, 65-67 (in Russian). 22 1096. Condensible gases in a McLend gauge. (USA) A method for the determination of the condensible gases in a McLeod gauge is described including estimation of the concentrations and determination of both the vacuum system pressure and the partial pressure due to non-condensible gases. The theory, vacuum system and gauge manipulation data, and difficulties are discussed. K B Wear, Rev Sci Instrum, 39 (2), 1968, 245-250. 22 1097. Measurements of gas pulses in the 1 torr range. (USA) A method for extending the pressure measurement range of the CK-5702 pentode ionization gauge in argon up to a pressure of 2 tort, is described. The method is based on reducing the ionization efficiency by increasing the negative bias applied to the plate and suppressor grid. R L Small, Rev Sci Instrum, 39 (2), 1968, 256-257. 22 1098. Observation of neutral gas pulses injected into a vacuum. (USA) The expansion of neutral gas into a vacuum was studied by using an ionization gauge. A vacuum system with a base pressure of 2 x 10-6 torr was used in which an amount of gas is suddenly introduced by a fast acting valve. It was found that the lightest gas (He) arrives first, and finally the heaviest (At). The lightest gas produces the pulse with the most rapid rise, and the steepness of the pressure rise curve decreases with increased distance from the inlet of the gas. R F Hotz and C K Manka, Rev Sci Instrum, 39 (2), 1968, 267-268. 22 1099. Drawings of micrometer U-tube manometers for the range up to 100 mm of mercury. (USA) Drawings with sufficient detail are presented so that micrometer U-tube manometers for use with mercury, oil, and water may be constructed. Measurements made with the oil manometer have an uncertainty of about 4 × 10-4 mm of Hg plus one part in 104 of the reading. Measurements made with the mercury manometer have an uncertainty of about 4 × 10-3 m m of Hg plus 8 parts in 10s of the reading. A M Thomas and J L Cross, Rep NBS-TN-420, Aug 1967, 18 pages (Sci Tech Aerospace Reps, 6 (4), 506, N68-12862). 22 1100. A survey of ionization vacuum gauges and their performance characteristics. (USA) The design of various types of ionization gauges is outlined, with particular attention to the design elements important to performance. The performance and the many factors affecting it are reviewed. Methods of calibration are discussed in some detail, including the use of volumetric pressure dividers, conductance pressure dividers and constant rate of pressure change methods. About 365 references are cited. W G Brombacber, Rep NBS-TN-298, Feb 1967, 65 pages (Rei Tech Aerospace Reps, 6 (4), 507, N68-13050).
23. P L U M B I N G
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1101. Superconductor-glass vacuum seals. (USA) The type of seal which is described, is similar to the Dumet type of copper-glass seal. This technique was very successful with niobiumtitanium copper-clad wire. The expansion coefficient of the alloy itself is sufficiently well matched to the lead glass. The seals were immersed in liquid helium at 4°K and leak tested with a helium mass-spectrometer leak detector. A seal of niobium-zirconium alloy (75:25) is also described. (Canada) P R Critehlow et al, Rev Sci Instrum. 39 (2), 1968, 251.
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(in Russian). 22 1091. Chromatic aberrations of a mass spectrometer with a step homogeneous magnetic field. (USSR) Chromatic aberrations were measured in a two-step mass spectrometer with pi-radian focusing. The possibility is shown of the choice of parameters to reduce the first order chromatic aberrations to zero. V I Karataev, Pribory Tekh Eksper, 13 (1), Jan-Feb 1968, 152-153
(in Russian). 22 1092. Insertion of samples into a mass spectrometer in the form of a molecular beam. (USSR) A molecular beam source is described for inserting vapours of the sample into the mass spectrometer ionization chamber. Results of analysis on the MI-1305 mass spectrometer show a high signal-tonoise ratio. (Romania) G Alexandru, Pribory Tekh Eksper, 13 (1), Jan-Feb 1968, 154-155
(in Russian). 22 1093. Cold cathode magnetron vacuum gauge. (USSR) A new magnetron gauge is described in which the cold cathode has linear characteristics in the range of 10-xl to 10-3 torr when an anode voltage of 5.5 kV and magnetic field of 1100 Oe are employed. When the field is below 1080 Oe, the characteristics are non-linear below 10-9 torr. Sensitivity, for N=, of 2 A/torr and relative sensitivities of 0.4 for H= and 0.12 for He were determined by calibration with an MM-14 M inverted magnetron gauge and an MI-12-8 Bayard-Alpert gauge. The parasitic currents correspond to the pressure of 10-x2 tort. The gaugehead is baked by an external furnace at 450°C for 40 hours and then is operated for 5 hours at the normal regime to prevent errors caused by degassing of the gaugehead. G A Nichiperovieh and I F Khanina, Pribory Tekh Eksper, 13 (1), Jan-Feb 1968, 156-159 (in Russian). 22 1094. Mass spectrometer ion collector with movable slots. (USSR) The design of the ion collection chamber in the MI-1305 mass spectrometer is described. The slot is movable and simultaneously a V-shaped collector and antidynatron electrode are also moved. The
V-shape of the collector was chosen to minimize secondary emission since ions are not incident in the normal direction. V P Strizhov et al, Pribory Tekh Eksper, 13 (2), March-April 1968, 156-157 (in Russian).
22 1095. Measuring devices of high accuracy. (USSR) Designed at the VNIIK laboratories as a primary standard, the VP vacuum gauge is based on a rotating piston with oil-sealing and spring loading. The position of the piston is determined with an M I R type microscope. A n accuracy of ± 1.5 × 10-~ torr in the range 0 to 75 torr was obtained. Anon, lzmcrit Tekh, no 4, 1968, 65-67 (in Russian). 22 1096. Condensible gases in a McLend gauge. (USA) A method for the determination of the condensible gases in a McLeod gauge is described including estimation of the concentrations and determination of both the vacuum system pressure and the partial pressure due to non-condensible gases. The theory, vacuum system and gauge manipulation data, and difficulties are discussed. K B Wear, Rev Sci Instrum, 39 (2), 1968, 245-250. 22 1097. Measurements of gas pulses in the 1 torr range. (USA) A method for extending the pressure measurement range of the CK-5702 pentode ionization gauge in argon up to a pressure of 2 tort, is described. The method is based on reducing the ionization efficiency by increasing the negative bias applied to the plate and suppressor grid. R L Small, Rev Sci Instrum, 39 (2), 1968, 256-257. 22 1098. Observation of neutral gas pulses injected into a vacuum. (USA) The expansion of neutral gas into a vacuum was studied by using an ionization gauge. A vacuum system with a base pressure of 2 x 10-6 torr was used in which an amount of gas is suddenly introduced by a fast acting valve. It was found that the lightest gas (He) arrives first, and finally the heaviest (At). The lightest gas produces the pulse with the most rapid rise, and the steepness of the pressure rise curve decreases with increased distance from the inlet of the gas. R F Hotz and C K Manka, Rev Sci Instrum, 39 (2), 1968, 267-268. 22 1099. Drawings of micrometer U-tube manometers for the range up to 100 mm of mercury. (USA) Drawings with sufficient detail are presented so that micrometer U-tube manometers for use with mercury, oil, and water may be constructed. Measurements made with the oil manometer have an uncertainty of about 4 × 10-4 mm of Hg plus one part in 104 of the reading. Measurements made with the mercury manometer have an uncertainty of about 4 × 10-3 m m of Hg plus 8 parts in 10s of the reading. A M Thomas and J L Cross, Rep NBS-TN-420, Aug 1967, 18 pages (Sci Tech Aerospace Reps, 6 (4), 506, N68-12862). 22 1100. A survey of ionization vacuum gauges and their performance characteristics. (USA) The design of various types of ionization gauges is outlined, with particular attention to the design elements important to performance. The performance and the many factors affecting it are reviewed. Methods of calibration are discussed in some detail, including the use of volumetric pressure dividers, conductance pressure dividers and constant rate of pressure change methods. About 365 references are cited. W G Brombacber, Rep NBS-TN-298, Feb 1967, 65 pages (Rei Tech Aerospace Reps, 6 (4), 507, N68-13050).
23. P L U M B I N G
23 : 46
1101. Superconductor-glass vacuum seals. (USA) The type of seal which is described, is similar to the Dumet type of copper-glass seal. This technique was very successful with niobiumtitanium copper-clad wire. The expansion coefficient of the alloy itself is sufficiently well matched to the lead glass. The seals were immersed in liquid helium at 4°K and leak tested with a helium mass-spectrometer leak detector. A seal of niobium-zirconium alloy (75:25) is also described. (Canada) P R Critehlow et al, Rev Sci Instrum. 39 (2), 1968, 251.
491