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562. Device for the automatic loading of liquid air vacuum traps.
Classified abstracts 559-568 flat aluminium rings. The data presented confirm that this type of gasket meets all the requirements of ultrahigh vacuum operation. Furthermore, these gaskets may be re-used many times. B Bernard et al, Le Vide, 22 (132) Nov-Dec 1967, 342-345 (in French). 23 559. A simple 50 kV feed-through plug and socket connector. (Great Britain) A small high-voltage feed-through plug and socket assembly is described. It utilizes a readily available parallel-bore ceramic tube. A brass body, gland nut and O ring serve as a clamp for the cable and as a reservoir for insulating fluid which is introduced through the small union on the side. H Wroe and R G Fowler, J Sci lnstrum, 44 (12), 1967, 1056-1057. 23 560. Compression characteristics of interaliy-unstrained rubber O-rings. (USA) The load-compression characteristics of toroidal rubber rings, when reduced to a non-dimensional form, fall on a single master curve. The Hertzian expression applies for contact width in terms of the load. The effectiveness of the seal depends upon the contact stress and the coefficient of friction between the rubber and the restraining surfaces. P B Lindley, J Inst Rubber Ind, I (4), 1967, 209-213. 25. BAFFLES, TRAPS AND REFRIGERATION E Q U I P M E N T 25 561. The development of an adsorption foreline trap suitable for quick cycliug vacuum systems. (Great Britain) An adsorption foreline trap suitable for conventionally pumped quick cycling vacuum systems has been evolved. The main consideration has been the reduction of water vapour take up by the adsorbent during pumping operations. By using 5-10 m m diameter activated alumina bails in an inline column geometry trap, the adsorption of water vapour during pumping was reduced to a minimum. With this material and trap design unlimited repeat pump-down cycles to less than i 00 millitorr were possible on a typical i 16-1itre volume chamber. The pump-down time in this case was extended from 3t minutes without the trap to 6~ minutes with the trap. Tests with steel balls instead of alumina balls showed that approximately half the extension to pump down time was due to physical obstruction to gas flow. M A Baker and G H Staniforth, Vacuum, 18 (I), Jan 1968, 17-20. 25 562. Device for the automatic loading of liquid air vacuum traps. (USA) The experimental arrangement and the functioning of a high vacuum system for automatically refilling liquid air traps are presented. The study was undertaken to find a method of eliminating oil vapours generated by the diffusion pump. Two electromagnetic valves regulate the flux of nitrogen in the circuit. (Italy) R Cratert, Rep ISS-66/41, Nov 1966, 11 pages (Sci Tech Aerospace Reps, 5 (50), 3622, N67-35155). 25 563. Small volume metal Dewar flask. (USSR) The design of a Dewar flask with a volume of 1 litre made from stainless steel is described. Space between walls is filled by 150 g of CaX zeolite. This isolating space is not pumped but filled by 10 to 15 cm 3 of solid CO~ which after its evaporation extrudes air from the space, which is then sealed by Teflon. The Dewar flask is designed for liquid nitrogen and operates for a year without inspection. V S Shan'ko et al, Zavodsk Lab, 33 (12), 1967, 1585 (in Russian). 28. HEATING E Q U I P M E N T AND T H E R M O M E T E R S 28 564. A new infra-red radiation pyrometer. (Great Britain) A new and sensitive type of infra-red radiation pyrometer is described. The basic instrument has two novel features. Firstly, it uses optical negative feedback from a semiconductor lamp to its lead sulphide photocell detector in order to give it overall stability, and secondly, it uses an efficient infra-red cut-off filter, a water cell, to improve the power law relationship of received energy to temperature, so reducing the effects of emissivity variation. The pyrometer covers a range of temperatures from less than 300°C upwards, depending on the
optical system. Without water cell filtering the minimum measuring temperature on low emissivity aluminium is less than 70°C. R S Young, J Sci lnstrum, 44 (12), 1967, 988-992. 28 565. The use of Chromel-Alumei thermocouples for the measurement of small temperature differences. (Great Britain) The changes in the differences between emf values of different thermocouples and a reference thermocouple before, during, and after a thermal treatment is described. The heat treatment improved the reproducibility of the measurement, so that small temperature differences can be measured with an accuracy of 0.1 °C. (Italy) P Pirro, J Sci Instrum, 44 (12), 1967, 1055-1056. 28 566. Low power arc heaters for low density hyperveloeity tunnels. (USA) By means of a simple layout the basic constructional features of arc heaters and their operating modes are described. A few remarks on the effect of aerodynamic and magnetic forces on the anode attachment region and on the contraction of the discharge by a nozzle are included. (Germany) K Stursberg, Rep DLR-Mitt-67-10; DVL-653, June 1967, 43 pages (in German) (Sci Tech Aerospace Reps, 5 (20), 3618, N67-34041).
III. Vacuum applications 30. EVAPORATION AND S P U T r E R I N G 30:20 All-metal apl~ratus for the investigation of sorption properties of metallic films. (See abstract number 53%) 3O 567. Preparation and properties of (Zn, Cd)S: Mn, Cu thin films. (Japan) Luminescence properties under uv light and dc field excitation are reported. X-ray diffraction patterns and emission spectra were studied. Solid solutions of the thin films with nearly the same composition as source material were obtained, when evaporated at 800°C or 1000°C. Emission spectra depended on the surface of the film, the glass substrate side or the opposite side, on which uv light was irradiated, especially in samples fired in air after deposition. The samples with latent luminescence centres due to M ions, at least on the glass substrate side, were obtained by the following method; powdered sample, with 10x 10-Sg atom added Mn ions per mole of host crystal, was evaporated at 1000°C, deposited on glass substrates, and then fired at 600°C in air or at 700°C in argon gas flow. However, effective field could not be applied to samples fired at above 600°C. Samples fired at 500°C in air had twice the emission intensity under simultaneous excitation of uv light and dc field than when under excitation by uv light alone. The above sample also showed electroluminescence under excitation of ac field. K Narita, J Vac Soc Japan, lO (I0), 1967, 350-357 (in Japanese). 3O 568. Some properties of gallium antimonide evaporated films. (Japan) Some properties of gallium antimonide films flash-evaporated on glass slides, with substrate temperatures between 100°C and 400°C, were determined experimentally. The thickness of samples was about 6000 A and evaporation rates were about 130 A/rain. X-ray diffraction patterns showed the existence of Sb crystals up to 250~C 300°C. Over 300°C the peaks for Sb crystals disappeared and the diffraction intensities of GaSb increased with substrate temperature. Between 350°C and 400°C, patterns corresponding to those of the bulk material were obtained. The transmittance of films deposited below 250°C was not observed in infrared region. But above 300°C discontinuity of transmittance began to appear in the range of 800-850 microns and the transmittance became constant at about 1800 microns, neglecting the interference term. Electrical properti~ determined at 400°C showed an impurity concentration and conductivity of 7.73. 101S/cms and 120i2-~cm -~ respectively at 300°K, giving a value for the mobility of 114.5 cm2/volt sec. Samples anhealed at 450°C for 2 hours in vacuum showed a lower Hall coefficient and layer conductivity than un-annealed film. T Kishl et al, J Vac Soc Japan, 10 (10), 1967, 358-363 (in Japanese).
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optical system. Without water cell filtering the minimum measuring temperature on low emissivity aluminium is less than 70°C. R S Young, J Sci lnstrum, 44 (12), 1967, 988-992. 28 565. The use of Chromel-Alumei thermocouples for the measurement of small temperature differences. (Great Britain) The changes in the differences between emf values of different thermocouples and a reference thermocouple before, during, and after a thermal treatment is described. The heat treatment improved the reproducibility of the measurement, so that small temperature differences can be measured with an accuracy of 0.1 °C. (Italy) P Pirro, J Sci Instrum, 44 (12), 1967, 1055-1056. 28 566. Low power arc heaters for low density hyperveloeity tunnels. (USA) By means of a simple layout the basic constructional features of arc heaters and their operating modes are described. A few remarks on the effect of aerodynamic and magnetic forces on the anode attachment region and on the contraction of the discharge by a nozzle are included. (Germany) K Stursberg, Rep DLR-Mitt-67-10; DVL-653, June 1967, 43 pages (in German) (Sci Tech Aerospace Reps, 5 (20), 3618, N67-34041).
III. Vacuum applications 30. EVAPORATION AND S P U T r E R I N G 30:20 All-metal apl~ratus for the investigation of sorption properties of metallic films. (See abstract number 53%) 3O 567. Preparation and properties of (Zn, Cd)S: Mn, Cu thin films. (Japan) Luminescence properties under uv light and dc field excitation are reported. X-ray diffraction patterns and emission spectra were studied. Solid solutions of the thin films with nearly the same composition as source material were obtained, when evaporated at 800°C or 1000°C. Emission spectra depended on the surface of the film, the glass substrate side or the opposite side, on which uv light was irradiated, especially in samples fired in air after deposition. The samples with latent luminescence centres due to M ions, at least on the glass substrate side, were obtained by the following method; powdered sample, with 10x 10-Sg atom added Mn ions per mole of host crystal, was evaporated at 1000°C, deposited on glass substrates, and then fired at 600°C in air or at 700°C in argon gas flow. However, effective field could not be applied to samples fired at above 600°C. Samples fired at 500°C in air had twice the emission intensity under simultaneous excitation of uv light and dc field than when under excitation by uv light alone. The above sample also showed electroluminescence under excitation of ac field. K Narita, J Vac Soc Japan, lO (I0), 1967, 350-357 (in Japanese). 3O 568. Some properties of gallium antimonide evaporated films. (Japan) Some properties of gallium antimonide films flash-evaporated on glass slides, with substrate temperatures between 100°C and 400°C, were determined experimentally. The thickness of samples was about 6000 A and evaporation rates were about 130 A/rain. X-ray diffraction patterns showed the existence of Sb crystals up to 250~C 300°C. Over 300°C the peaks for Sb crystals disappeared and the diffraction intensities of GaSb increased with substrate temperature. Between 350°C and 400°C, patterns corresponding to those of the bulk material were obtained. The transmittance of films deposited below 250°C was not observed in infrared region. But above 300°C discontinuity of transmittance began to appear in the range of 800-850 microns and the transmittance became constant at about 1800 microns, neglecting the interference term. Electrical properti~ determined at 400°C showed an impurity concentration and conductivity of 7.73. 101S/cms and 120i2-~cm -~ respectively at 300°K, giving a value for the mobility of 114.5 cm2/volt sec. Samples anhealed at 450°C for 2 hours in vacuum showed a lower Hall coefficient and layer conductivity than un-annealed film. T Kishl et al, J Vac Soc Japan, 10 (10), 1967, 358-363 (in Japanese).
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