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1095. Calibration of vacuum gauges
Classified abstracts 1088--1097 access for gas molecules to pumping surfaces of the pump. Degassing is performed by heat radiation of the anode when supply of cooling water is stopped. S I Miroshkin et al, Elektron Tekh Mikroelektron, 3, 1970, 143-145
(in Russian). 21 1088. Magnetic discharge pumps with cathodes of porous titanium. (USSR) Construction and characteristics of diode magnetic discharge pumps with porous titanium cathodes are considered. These pumps are intended for additional pumping of sealed devices. Compared to pumps using compact titanium, the porous titanium pumps show a higher pumping speed for argon and two-fold increase in pumping speed for active gases. The ultimate pressure is below 10 z0 torr. It is shown that for the pumping of pure argon, the porous cathode pumps are stable and argon instabilities are not observed. In the switched-off state these pumps can be used for maintaining high vacuum in devices during prolonged storage. A I Skakun et al, Elektron Tekh Elektron SVCh, 1, 1971, 100-110 (in
Russian). 21 1089. Evacuation of equipment for ion-plasma sputtering by electrical discharge pumps. (USSR) The possibility of utilizing electrical-discharge pumps (type NEM-300) for the evacuation of ion-plasma sputtering equipment is investigated. The conditions for stable operation at a working pressure of 5 to 10 × 10-4 tort are determined. The composition of the working ambient at these pressures is analyzed with the aid of an omegatron mass spectrometer. It is found that the ambient in the working chamber of the equipment is not contaminated by accumulation of products of pumping of chemically active gases. The efficiency of the application of electrical-discharge pumps in the ion-sputtering equipments is demonstrated. F G Tomashpolskiy et al, Elektron Tekh Radiodetali, 3, 1970, 93-100
(in Russian). 22. GAUGES 22 1090. A vacuum gauge. (USSR) A method of securing a stable relationship between the readings of a vacuum gauge and the actual pressure at the instant of switching from one working range to another is described. The method is based on the incorporation of voltage limiters, the inputs of which are connected to the outputs of the vacuum sensors, while their outputs are connected in series with the corresponding input of the measuring unit. By duly adjusting the working parameters of the individual voltage limiters, a stable reading of the gauge on passing from one range to another may be achieved, e.g., the gauge will read from 0 to 10 units in the pressure range 10 -° to 10-8 torr and from 10 to 20 units in the pressure range 10-2 to 50 torr. Tests confirm the validity of this principle. L I Trakhtenberg et al, USSR Patent, No 273,493, app117th Jan 1969, publd 15th Sept 1970. 22 1091. An ionization gauge with plane electrode system and emission current modulation. (Czechoslovakia) An ionization gauge with parallel plane electrodes is studied. The emission current modulation by means of a low-frequency signal, the problem of the ratio of the anode current to the total emission current and the effect of this ratio on the ion current are dealt with. The calibration curves of the gauges with and without emission current modulation are presented and the effect of the capacitance between the ion collector and the modulator grid on the lower limit of the gauge measuring range is discussed. The results of the gauge calibration in a magnetic field prove the usefulness of this gauge for pressure measurements in magnetic fields of variable magnitude, for example the hot plasma experiments in mirror machines. It is shown that the dependence of the gauge sensitivity on the magnetic field intensity is rather weak. As the magnetic induction grows from 0 to 500 G, it attains approximately double its value but changes of the magnetic field induction between 0.5 to 2 kG produce virtually no further changes of gauge sensitivity. P Repa, Czech JPhys, B21 (3), 1971, 309-321.
22 1092. Semiconductor electrometer amplifiers. (USSR) A review is presented of semiconductor electrometer amplifiers which can also be used in ionization gauges and mass spectrometers. A K Osipov, Prib Tekh Eksper, No 1, 1971, 7-18 (in Russian). 22 1093. Three-dimensional quadrnpole mass spectrometer with ion storage. (USSR) A three-dimensional quadrupole mass spectrometer with ion storage is described. The theoretical basis for the trapping of charged particles in a three-dimensional, rotationally symmetric, quadrupole field is discussed. The stability diagram o f a quadrupole mass spectrometer with ion storage is presented. The electrodes are made of stainless steel and ceramic insulators are placed between the electrodesl Both the minimum radius of the ring and half the minimum vertica. separation between the caps are equal to 5 mm. Head construction permits baking to 400°C. A ribbon tungsten cathode of 2 mm-width serves as an electron source. The circuit diagram of the mass spectrometer is presented. Residual gas is ionized by a pulsed electron beam introduced through a 0.5 mm diameter-opening in the inlet cap. The electron beam pulse lasts 10/~sec. After 300 ~sec of ion separation, a 10 #sec pulse is applied to the outlet cap with slits for stored ion extraction in the electron multiplier. The instrument works satisfactorily up to a pressure of 10 -8 torr. The resolving power measured at half the peak height is equal to 120. The sensitivity of the instrument is 10 -5 A/torr. The instrument is intended for partial pressure analysis in vacuum systems. E P Sheretov et al, Prib Tekh Eksper, No 1, 1971, 166-168 (in Russian). 22 1094. Chromatograph coupling to mass spectrometer. (USSR) A chromatograph coupling to a mass spectrometer is described, whereby multi-component gas mixtures may be analyzed. A N Aleksandrov et al, Prib Tekh Eksper, No 1, 1971, 169-170 (in
Russian). 22 1095. Calibration of vacuum gauges. (Czechoslovakia) The direct and projection methods of vacuum gauge calibration are described. The dynamic projection method is given special attention and a new modification of the equipment with the "transfer" of the calibration pressure to the reference level is described. The equipment allows calibration in the pressure range of 10-8 to 10-7 tort using the dynamic method and in the pressure range of 10 to 10-8 torr using the static method with direct comparison with standard pressure. The system has three chambers. The first chamber is connected to the standard gauge. The calibrated gauge is connected to the second chamber. The third chamber with a monitoring gauge is evacuating. Between the first, second and third chambers, vacuum conductanees with values in the ratio of 1:104 are placed. The system is evacuated by an oil diffusion pump and an orbitron pump with ultimate pressure of 10-8 torr. In all inlet and outlet ports freezing traps are used. Fritted glass with conductance of 1.4 × 10-3 litres/sec for air is used as the first orifice. The second orifice is formed by an opening with an area of 0.938 cm 8. McLeod gauge with capillaries of 8 mm diameter, U-gauge and Knudsen gauge are used as standard gauges. A Blaha, Jemna Mech Optika, 16 (3), March 1971, 68-71 (in Czech). 22 1096. Prism mass spectrometer with energy focusing. (USSR) Construction and performance of a prism mass spectrometer with energy focusing are described. The energy focusing is attained by the combined action of magnetic and electrostatic prisms. A maximum value of resolving power at half-width of peak height of 14 x 108 was achieved with a miniature analyzer. Three mercury diffusion pumps maintain a pressure of 2 × 10-7 torr in the analyzer chamber. V M Kelman et al, Zh Tekh Fiz, 41 (1), Jan 1971, 173-179 (in Russian). 22 1097. Performance of a modified buried collector gauge. (USA) The performance of a modified buried collector gauge was determined over a (helium) pressure range 10-z3-10-4 torr. Optimum operating parameters were empirically chosen. With 5.0-mA emission current and 100-V grid to filament potential, the x-ray photoelectron current of the gauge was estimated to be 5.2 × 10-13 A. By subtracting the measured background current, linear response was obtained between 6× 10 -13 and 3 × 10 -4 tort (He) with a gauge sensitivity of
405
(in Russian). 21 1088. Magnetic discharge pumps with cathodes of porous titanium. (USSR) Construction and characteristics of diode magnetic discharge pumps with porous titanium cathodes are considered. These pumps are intended for additional pumping of sealed devices. Compared to pumps using compact titanium, the porous titanium pumps show a higher pumping speed for argon and two-fold increase in pumping speed for active gases. The ultimate pressure is below 10 z0 torr. It is shown that for the pumping of pure argon, the porous cathode pumps are stable and argon instabilities are not observed. In the switched-off state these pumps can be used for maintaining high vacuum in devices during prolonged storage. A I Skakun et al, Elektron Tekh Elektron SVCh, 1, 1971, 100-110 (in
Russian). 21 1089. Evacuation of equipment for ion-plasma sputtering by electrical discharge pumps. (USSR) The possibility of utilizing electrical-discharge pumps (type NEM-300) for the evacuation of ion-plasma sputtering equipment is investigated. The conditions for stable operation at a working pressure of 5 to 10 × 10-4 tort are determined. The composition of the working ambient at these pressures is analyzed with the aid of an omegatron mass spectrometer. It is found that the ambient in the working chamber of the equipment is not contaminated by accumulation of products of pumping of chemically active gases. The efficiency of the application of electrical-discharge pumps in the ion-sputtering equipments is demonstrated. F G Tomashpolskiy et al, Elektron Tekh Radiodetali, 3, 1970, 93-100
(in Russian). 22. GAUGES 22 1090. A vacuum gauge. (USSR) A method of securing a stable relationship between the readings of a vacuum gauge and the actual pressure at the instant of switching from one working range to another is described. The method is based on the incorporation of voltage limiters, the inputs of which are connected to the outputs of the vacuum sensors, while their outputs are connected in series with the corresponding input of the measuring unit. By duly adjusting the working parameters of the individual voltage limiters, a stable reading of the gauge on passing from one range to another may be achieved, e.g., the gauge will read from 0 to 10 units in the pressure range 10 -° to 10-8 torr and from 10 to 20 units in the pressure range 10-2 to 50 torr. Tests confirm the validity of this principle. L I Trakhtenberg et al, USSR Patent, No 273,493, app117th Jan 1969, publd 15th Sept 1970. 22 1091. An ionization gauge with plane electrode system and emission current modulation. (Czechoslovakia) An ionization gauge with parallel plane electrodes is studied. The emission current modulation by means of a low-frequency signal, the problem of the ratio of the anode current to the total emission current and the effect of this ratio on the ion current are dealt with. The calibration curves of the gauges with and without emission current modulation are presented and the effect of the capacitance between the ion collector and the modulator grid on the lower limit of the gauge measuring range is discussed. The results of the gauge calibration in a magnetic field prove the usefulness of this gauge for pressure measurements in magnetic fields of variable magnitude, for example the hot plasma experiments in mirror machines. It is shown that the dependence of the gauge sensitivity on the magnetic field intensity is rather weak. As the magnetic induction grows from 0 to 500 G, it attains approximately double its value but changes of the magnetic field induction between 0.5 to 2 kG produce virtually no further changes of gauge sensitivity. P Repa, Czech JPhys, B21 (3), 1971, 309-321.
22 1092. Semiconductor electrometer amplifiers. (USSR) A review is presented of semiconductor electrometer amplifiers which can also be used in ionization gauges and mass spectrometers. A K Osipov, Prib Tekh Eksper, No 1, 1971, 7-18 (in Russian). 22 1093. Three-dimensional quadrnpole mass spectrometer with ion storage. (USSR) A three-dimensional quadrupole mass spectrometer with ion storage is described. The theoretical basis for the trapping of charged particles in a three-dimensional, rotationally symmetric, quadrupole field is discussed. The stability diagram o f a quadrupole mass spectrometer with ion storage is presented. The electrodes are made of stainless steel and ceramic insulators are placed between the electrodesl Both the minimum radius of the ring and half the minimum vertica. separation between the caps are equal to 5 mm. Head construction permits baking to 400°C. A ribbon tungsten cathode of 2 mm-width serves as an electron source. The circuit diagram of the mass spectrometer is presented. Residual gas is ionized by a pulsed electron beam introduced through a 0.5 mm diameter-opening in the inlet cap. The electron beam pulse lasts 10/~sec. After 300 ~sec of ion separation, a 10 #sec pulse is applied to the outlet cap with slits for stored ion extraction in the electron multiplier. The instrument works satisfactorily up to a pressure of 10 -8 torr. The resolving power measured at half the peak height is equal to 120. The sensitivity of the instrument is 10 -5 A/torr. The instrument is intended for partial pressure analysis in vacuum systems. E P Sheretov et al, Prib Tekh Eksper, No 1, 1971, 166-168 (in Russian). 22 1094. Chromatograph coupling to mass spectrometer. (USSR) A chromatograph coupling to a mass spectrometer is described, whereby multi-component gas mixtures may be analyzed. A N Aleksandrov et al, Prib Tekh Eksper, No 1, 1971, 169-170 (in
Russian). 22 1095. Calibration of vacuum gauges. (Czechoslovakia) The direct and projection methods of vacuum gauge calibration are described. The dynamic projection method is given special attention and a new modification of the equipment with the "transfer" of the calibration pressure to the reference level is described. The equipment allows calibration in the pressure range of 10-8 to 10-7 tort using the dynamic method and in the pressure range of 10 to 10-8 torr using the static method with direct comparison with standard pressure. The system has three chambers. The first chamber is connected to the standard gauge. The calibrated gauge is connected to the second chamber. The third chamber with a monitoring gauge is evacuating. Between the first, second and third chambers, vacuum conductanees with values in the ratio of 1:104 are placed. The system is evacuated by an oil diffusion pump and an orbitron pump with ultimate pressure of 10-8 torr. In all inlet and outlet ports freezing traps are used. Fritted glass with conductance of 1.4 × 10-3 litres/sec for air is used as the first orifice. The second orifice is formed by an opening with an area of 0.938 cm 8. McLeod gauge with capillaries of 8 mm diameter, U-gauge and Knudsen gauge are used as standard gauges. A Blaha, Jemna Mech Optika, 16 (3), March 1971, 68-71 (in Czech). 22 1096. Prism mass spectrometer with energy focusing. (USSR) Construction and performance of a prism mass spectrometer with energy focusing are described. The energy focusing is attained by the combined action of magnetic and electrostatic prisms. A maximum value of resolving power at half-width of peak height of 14 x 108 was achieved with a miniature analyzer. Three mercury diffusion pumps maintain a pressure of 2 × 10-7 torr in the analyzer chamber. V M Kelman et al, Zh Tekh Fiz, 41 (1), Jan 1971, 173-179 (in Russian). 22 1097. Performance of a modified buried collector gauge. (USA) The performance of a modified buried collector gauge was determined over a (helium) pressure range 10-z3-10-4 torr. Optimum operating parameters were empirically chosen. With 5.0-mA emission current and 100-V grid to filament potential, the x-ray photoelectron current of the gauge was estimated to be 5.2 × 10-13 A. By subtracting the measured background current, linear response was obtained between 6× 10 -13 and 3 × 10 -4 tort (He) with a gauge sensitivity of
405