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666. Leak detection and detectors
Classified abstracts 657--671 22 : 56 4i57. Factors affecting the operation of the quartz oscillator gauge.
(Great Britain) The energy transfer from a vibratory quartz crystal at frequencies above 50 Kc/sec is shown to be affected by the pressure of standing waves within the gauge envelope. When these are avoided by mounting the crystal within a sound-absorbing enclosure, the rate o f energy transfer through the gas is proportional to p(yM) ½over the range of pressures from 10 -1 to 760 torr. The effects of sound absorption in the gas due to relaxation processes are shown to be negligible at pressures below 10 -1 torr. The use of a low-frequency crystal is shown to avoid the effects due to standing waves and absorption in the gas. An amplitude-stabilised version of the gauge is described with details of its performance, and the effects of crystal geometry upon sensitivity discussed. (Great Britain) D J Pacey, Vacuum, 15 (3), March 1965, 95-98. 22 658. A new diaphragm manometer with a semiconductor strain gauge as pressure sensing element. (Great Britain) The diaphragm manometer described is intended for remote measurement apd control of pressure in the range 1 tort to atmospheric. Any deflection of the diaphragm produces a change in the electrical resistance of a semi-conductor strain gauge attached to it. The resulting d.c. signal is transmitted by cable and amplified. In the most sensitive range, the output voltage corresponding to 10 torr amounts to 10 volts. The temperature coefficient of the instrument is about 0.2 per cent per °C. The overall drift of the gauge after prolonged exposure to the atmosphere is less than 0.2 tort.
is propagated as an elastic wave, which can be detected at a distance. Sparks can be localized by this method with a precision of ~: 1 mm. (Netherlands) C Granelli, Nuclear lnstrum Methods, 31 (1), Dec 1964, 29-34.
27. Leak detectors and leak detection 27 666. Leak detection and detectors. (Great Britain) While continuous advances in the design of vacuum components and in the technique of construction have gradually reduced the incidence of "built in" leaks in vacuum systems, the parallel development of leak detectors has facilitated the detection of smaller and smaller leaks, until, at the present time, the lowest pressure attainable in a metal vacuum system is governed by the rate of outgassing of the constructional material and in a glass system by the rate of diffusion of atmospheric helium through the glass. When a vacuum system is to be constructed, it is advisable to test each individual item for leakage before assembly and then start construction of the system at the pumps. It is better not to have any leaks in the first place, than to assume that the effects of bad workmansihp are easily overcome by application of a sensitive leak detector. (Great Britain) A H Turnhull, Vacuum, 15 (1), Jan 1965, 3-11. 27 667. Audible leak detector. (Great Britain) Anon, Electronic Equipment News, 6, April 1965, p 61.
(Japan)
29. Miscellaneous
O Tsukakoshi et al, Vacuum, 14 (11), Nov 1964, 425~127.
22 659. Improvement on rotary McLeod gauge. (Japan) A new type of rotary McLeod gauge is described, covering the pressure range 10-1-10 -5 torr. It uses a tapering capillary and requires only 1½ cc of mercury. It is claimed that pressure measurement only requires 5 to 10 sec. Y Gosho, Sci Pap lnst Phys Chem Res, 58 (3}, Sept 1964, 103-105. 22 660. Fiowmeter measures extremely-low viscous flow rates. (USA) L M Polentz, Chemical Engineering, 72 (8), April 1965, 204-206.
29 668. Vacuum-jacketed hydrofluoric acid solution calorimeter. (USA) The vacuum-jacketed calorimeter has a cooling constant of 0.6 cal-deg-l-min-1, which is less than one quarter that of the airjacketed calorimeters normally used. (USA) R A Roble, Rev Sci Inst, 36 (4), April 1965, 484-486.
III. Vacuum applications
23. Plumbing
30. Evaporation and sputtering
23 Epoxy resin seals to copper and nylon for cryogenic applications. See abstract number 629. 23 : 52 661. An efficient joining technique---diffusion bonding. (USA) E C Vicars, Metal Progress, 87 (4), April 1965, 125-130. 23 : 45 662. Joining dissimilar metals. (USA) R R Irving, Iron Age, 195 (13), April 1965.
3O Construction of a titanium atomizer with electronic heating. See abstract number 651. 30 Dynamical operation of the in-llne cryotron in bistable circuits. See abstract number 664. 30 Laser welding of interconnexions in semiconductor integrated circuits. See abstract number 711. 30 : 41 669. Vapour deposited tungsten coatings on graphite. (USA) Vapour-deposited tungsten coatings on graphite are liable to crack unless a graphite with controlled thermal expansion is chosen as substrate. The author investigated what effect, if any, the plating parameters had on the tendency to crack. Deposition temperature, H U W F J r a t i o and gas velocity were varied and their effect on hardness and grain size of the deposit studied. (USA) V A Nieberlein, Amer Ceram Soc Bull, Jan 1965, 14-22. 3O 670. Texture of evaporated CdS films. (Germany) Influence of nature of substrate on the structure of CdS was studied in the case of glass, polished CaF2 and CaF~ cleavage surfaces. It appears that preliminary surface treatment as well as nature of substrate surface affects the deposited film. C O Muller and H Peibst, Phys Status Solids, 8 (1), K51-K52. 30 : 41 671. Epitaxy in thin films of EuS. (USA) Thin films of EuS that are essentially monocrystalline have been grown on single-crystal substrates composed of other crystal structures by vapour deposition. It appears that the crystal structure of the substrate is the critical criterion for epitaxial growth. Another requirement is the temperature of the substrate. Good results were obtained with substrates of NaBr, NaCI, MgO of
24. Valves 24 663. Vacuum valves. (Great Britain) Anon, Nuclear Engineering, 10 (107), March 1965, 110.
26. Automatic protective and control equipment 26 : 30 : 56 664. Dynamical operation of the in-line cryotron in bistable circuits.
( Great Britain) The authors begin by contrasting the presently achieved cryotron transfer times of 25 ns with the predicted value of only 1.5 ns. They give a very short review of the vacuum deposition requirements and a description (with illustrations) of a thin-film cryotron circuit used in the experiments they report on switching-time investigation. A E Brennemann et al, Proc 1EEE, 52, March 1964, 228-238. 26:18 665. Localization of sparks in spark chambers through magnetostrictive effects. (Netherlands) By using an array of parallel wires made of a magnetostrictive material as one of the spark-chamber electrodes, an elastic deformation is produced at the position of the spark. This deformation
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(Great Britain) The energy transfer from a vibratory quartz crystal at frequencies above 50 Kc/sec is shown to be affected by the pressure of standing waves within the gauge envelope. When these are avoided by mounting the crystal within a sound-absorbing enclosure, the rate o f energy transfer through the gas is proportional to p(yM) ½over the range of pressures from 10 -1 to 760 torr. The effects of sound absorption in the gas due to relaxation processes are shown to be negligible at pressures below 10 -1 torr. The use of a low-frequency crystal is shown to avoid the effects due to standing waves and absorption in the gas. An amplitude-stabilised version of the gauge is described with details of its performance, and the effects of crystal geometry upon sensitivity discussed. (Great Britain) D J Pacey, Vacuum, 15 (3), March 1965, 95-98. 22 658. A new diaphragm manometer with a semiconductor strain gauge as pressure sensing element. (Great Britain) The diaphragm manometer described is intended for remote measurement apd control of pressure in the range 1 tort to atmospheric. Any deflection of the diaphragm produces a change in the electrical resistance of a semi-conductor strain gauge attached to it. The resulting d.c. signal is transmitted by cable and amplified. In the most sensitive range, the output voltage corresponding to 10 torr amounts to 10 volts. The temperature coefficient of the instrument is about 0.2 per cent per °C. The overall drift of the gauge after prolonged exposure to the atmosphere is less than 0.2 tort.
is propagated as an elastic wave, which can be detected at a distance. Sparks can be localized by this method with a precision of ~: 1 mm. (Netherlands) C Granelli, Nuclear lnstrum Methods, 31 (1), Dec 1964, 29-34.
27. Leak detectors and leak detection 27 666. Leak detection and detectors. (Great Britain) While continuous advances in the design of vacuum components and in the technique of construction have gradually reduced the incidence of "built in" leaks in vacuum systems, the parallel development of leak detectors has facilitated the detection of smaller and smaller leaks, until, at the present time, the lowest pressure attainable in a metal vacuum system is governed by the rate of outgassing of the constructional material and in a glass system by the rate of diffusion of atmospheric helium through the glass. When a vacuum system is to be constructed, it is advisable to test each individual item for leakage before assembly and then start construction of the system at the pumps. It is better not to have any leaks in the first place, than to assume that the effects of bad workmansihp are easily overcome by application of a sensitive leak detector. (Great Britain) A H Turnhull, Vacuum, 15 (1), Jan 1965, 3-11. 27 667. Audible leak detector. (Great Britain) Anon, Electronic Equipment News, 6, April 1965, p 61.
(Japan)
29. Miscellaneous
O Tsukakoshi et al, Vacuum, 14 (11), Nov 1964, 425~127.
22 659. Improvement on rotary McLeod gauge. (Japan) A new type of rotary McLeod gauge is described, covering the pressure range 10-1-10 -5 torr. It uses a tapering capillary and requires only 1½ cc of mercury. It is claimed that pressure measurement only requires 5 to 10 sec. Y Gosho, Sci Pap lnst Phys Chem Res, 58 (3}, Sept 1964, 103-105. 22 660. Fiowmeter measures extremely-low viscous flow rates. (USA) L M Polentz, Chemical Engineering, 72 (8), April 1965, 204-206.
29 668. Vacuum-jacketed hydrofluoric acid solution calorimeter. (USA) The vacuum-jacketed calorimeter has a cooling constant of 0.6 cal-deg-l-min-1, which is less than one quarter that of the airjacketed calorimeters normally used. (USA) R A Roble, Rev Sci Inst, 36 (4), April 1965, 484-486.
III. Vacuum applications
23. Plumbing
30. Evaporation and sputtering
23 Epoxy resin seals to copper and nylon for cryogenic applications. See abstract number 629. 23 : 52 661. An efficient joining technique---diffusion bonding. (USA) E C Vicars, Metal Progress, 87 (4), April 1965, 125-130. 23 : 45 662. Joining dissimilar metals. (USA) R R Irving, Iron Age, 195 (13), April 1965.
3O Construction of a titanium atomizer with electronic heating. See abstract number 651. 30 Dynamical operation of the in-llne cryotron in bistable circuits. See abstract number 664. 30 Laser welding of interconnexions in semiconductor integrated circuits. See abstract number 711. 30 : 41 669. Vapour deposited tungsten coatings on graphite. (USA) Vapour-deposited tungsten coatings on graphite are liable to crack unless a graphite with controlled thermal expansion is chosen as substrate. The author investigated what effect, if any, the plating parameters had on the tendency to crack. Deposition temperature, H U W F J r a t i o and gas velocity were varied and their effect on hardness and grain size of the deposit studied. (USA) V A Nieberlein, Amer Ceram Soc Bull, Jan 1965, 14-22. 3O 670. Texture of evaporated CdS films. (Germany) Influence of nature of substrate on the structure of CdS was studied in the case of glass, polished CaF2 and CaF~ cleavage surfaces. It appears that preliminary surface treatment as well as nature of substrate surface affects the deposited film. C O Muller and H Peibst, Phys Status Solids, 8 (1), K51-K52. 30 : 41 671. Epitaxy in thin films of EuS. (USA) Thin films of EuS that are essentially monocrystalline have been grown on single-crystal substrates composed of other crystal structures by vapour deposition. It appears that the crystal structure of the substrate is the critical criterion for epitaxial growth. Another requirement is the temperature of the substrate. Good results were obtained with substrates of NaBr, NaCI, MgO of
24. Valves 24 663. Vacuum valves. (Great Britain) Anon, Nuclear Engineering, 10 (107), March 1965, 110.
26. Automatic protective and control equipment 26 : 30 : 56 664. Dynamical operation of the in-line cryotron in bistable circuits.
( Great Britain) The authors begin by contrasting the presently achieved cryotron transfer times of 25 ns with the predicted value of only 1.5 ns. They give a very short review of the vacuum deposition requirements and a description (with illustrations) of a thin-film cryotron circuit used in the experiments they report on switching-time investigation. A E Brennemann et al, Proc 1EEE, 52, March 1964, 228-238. 26:18 665. Localization of sparks in spark chambers through magnetostrictive effects. (Netherlands) By using an array of parallel wires made of a magnetostrictive material as one of the spark-chamber electrodes, an elastic deformation is produced at the position of the spark. This deformation
383