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912. A multiprobe miniature thermistor system for the measurement of temperature profiles
Classified
abstracts
906-915
23 23. PLUMBING 906. Hermetic joint for connecting parts of high-vacuum systems. (USSR) A new form of hermetic joint for connecting parts of high vacuum systems is proposed; it is distinguished from its predecessors in that it incorporates three coaxially-disposed flanges, of which the two main elements are identical; these are fixed in an axial direction relative to the parts being joined by means of sprung guides and other compensators, while the third, intermediate flange lies between them and is provided with additional sealing rings. Mutual compression of the flanges may be achieved by applying different gas pressures to the constituent parts; this makes remote control of the system relatively easy. The actual contact elements may be made of lead (or soft alloys), or alternatively rubber. E V Rudnev, Soviet Patent, class F 16 I, 23100. No 369335, publd 17 December 1973 (in Russian). ‘3 907. Sealing of a vacuum chamber. (USSR) The vacuum-chamber seal here described differs from existing versions in that on the outer shoulder of the chamber additional flexible strips are provided, together with a spring system which presses them against the parts to be sealed. The springs and strips provide additional sealing forces which come into play, in particular, if the unit as a whole is subjected to varying temperatures or pressures. The ultimate contacts may be either metal (cast iron or bronze) or alternatively asbestos cord. V P Murovtsev and A E Markin, Soviet Patent, class F I6 j. 15/06, No 355423, publd 28 October 1972 (in Russian). 23 908. Inspection window for vacuum chambers. (USSR) A device intended to increase the service life of vacuum installations incorporating screened inspection windows is described. The service life is increased by having the screen fixed rigidly to the vacuum chamber, making the inspection glass movable relative to the screen, and connecting it to the vacuum chamber by means of a flexible hermetic seal. The screen protects the glass from contamination by materials evaporating inside the vacuum chamber except over the small area corresponding to the aperture in the screen. A simple mechanism is therefore provided to move the glass periodically relative to the screen so as to present new, uncontaminated areas to the aperture. In this way the frequency of complete replacements of the inspection window is greatly reduced. V A Pupko and V E Minaichev, Soviet Patent, class C 23 c. l3/08, No 392166, publd I4 December 1973 (in Russian). 909. Demountable vacuum-tight joint. (USSR) An invention designed to improve the efficiency of vacuum ioints subjected to repeated changes of working temperature and pressure is described. The joint is furnished with a cylindrical elastic ‘belt’ connecting a conical projection to one of the parts of the joint, metallic sealing rings also being incorporated. The geometry of the belt and the sealing rings is so adjusted that the combination of elastic forces and thermal expansion called into play as a result of varying temperature and pressures always keeps the contact between the two parts of the joint vacuum-tight. V D Pak and A I Saraev, Soviet Patent, class F I6 j, I S/OS, No 396503, publd I5 January 1974 (in Russian).
24. VALVES ‘4 910. A gas leak. (USSR) A new type of gas-leak construction designed to prevent radial displacements of the gates and valves on heating these in a nonuniform manner above the normal working temperature is proposed. This aim is achieved by incorporating a special guide, engaging with the tail-piece of the gate rod, which is made much longer than that encountered in simpler gas leaks. The gap passing gas into the vessel is regulated by a mechanism based on differential thermal expansion; the gap may thus easily be controlled from a distance by varying the voltage on a small heater unit. 1, N Rozanov and V M Lebedev, Soviet Patenr, class F 16 k. I/04. No 396505, publd I5 January 1974 (in Russian). 288
25. BAFFLES,
TRAPS
AND
REFRIGERATION
EQUIPMEN
‘5 911. A cryogenic vacuum trap. (USSR) A new type of cryogenic trap aimed at protecting the high-vacuum parts of vacuum installations from the deposition of oil vapour emitted by the backing pump is described, its main aim being that of improving operating efficiency and reducing coolant consumption. This is achieved by incorporating an annular Dewar vessel, surrounding the main gas-flow tube and also partly embracing the chamber containing the coolant. The evaporating coolant emerge\ from the Dewar through a specially-shaped gap. In this way the temperature gradient is smodthed gnd undue loss of coolant is avoided. Loss is further reduced bv the use of a specially-designed valve system. I R Kirichek et al, Soviet Patent, class F 04 f; 9106. F 25 d, 3! IO. NC, 398762, publd I2 February I974 (in Russian). 28. HEATING
EQUIPMENT
AND
THERMOMETERS
912. A multiprobe miniature thermistor system for the measurement of temperature profiles. (USA) A new instrument for the determination of fine temperature profiler, in hot. corrosive, electrically conductive, unsteady two-phase fluid systems under vacuum or pressure is described. It features simultaneour measurement of temperatures at close locations, by a column ot miniature (0.25 mm dia) thermistors mounted at the tips of supporting hypodermic tubes, and streamlined design that minimizes hydrodynamic and thermal disturbances at the measured locations. Some of the techniques used in the construction, such as the welding. insulation, and handling of fine wires (0.025 mm dia), are of interest in many other applications. The instrument has been used to measure temoerature distributions with an accuracv of eO.02 C in a model of a flash-evaporator stage used for the desalination of saline water, and thus provided new and quantitatively significant data about the process. N Lior et al, Rev Scient Instrum. 45 (I I ). 1974. 1340--l 343.
III.
Vacuum
30. EVAPORATION
applications AND
SPUTTERING
30 913. Structural dependence of electrical conductivity of thin tellurium films. (USA) Tellurium films were deposited on glass substrates and maintained in vacuum during the course of the measurement of electrical conductivity. The films were found by electron microscopy to have polycrystalline structure with a grain size dependent on deposition parameters. The electrical conductivity increased with increasing thickness. with increasing rate of deposition. and with the transition from the nonannealed to the annealed state. The increase in deposition rate from 100 to 1000 Aimin led to an increase in both grain size and number of surface defects. Annealing resulted in a further increase in grain size but in a decrease in the number of defects. The conductivity could further be explained in terms of mobility and carrielconcentration, the former increasing with increasing grain size and decreasing defects, and the latter increasing with increasing defects. A comparison of quenched and annealed films confirms the dependence of mobility on the number of defects. M A Dinno et al, J Appl Phys. 45 (8), 1974, 3328-333 I. 914. A shadow mask for sputtered films. (USA) Use of a magnet to clamp a magnetic metal mask to the substrate during sputtering resulted in good edge definition in thin film patterns. F W Ingle, Rev Went fnstrum, 45 (1 I ), 1974, 1460-1461, 3(l 915. Nucleus growth rate of vacuum-deposited thin films. (USA) The nucleus growth rate in the initial stages of thin-film formation has been discussed on the basis of the collision theory of a twodimensional gas and the diffusion theory of surface adatoms. It ha\ been shown that, in the formulation of the area of the capture zone. the former theory is suitable for small nuclei (p . 0.27) and the latter for large nuclei (p 0.27), p being the ratio of the nucleus radius to one half of the mean diffusion distance of single adatoms. The foregoing theoretical considerations were examined by the deposition
abstracts
906-915
23 23. PLUMBING 906. Hermetic joint for connecting parts of high-vacuum systems. (USSR) A new form of hermetic joint for connecting parts of high vacuum systems is proposed; it is distinguished from its predecessors in that it incorporates three coaxially-disposed flanges, of which the two main elements are identical; these are fixed in an axial direction relative to the parts being joined by means of sprung guides and other compensators, while the third, intermediate flange lies between them and is provided with additional sealing rings. Mutual compression of the flanges may be achieved by applying different gas pressures to the constituent parts; this makes remote control of the system relatively easy. The actual contact elements may be made of lead (or soft alloys), or alternatively rubber. E V Rudnev, Soviet Patent, class F 16 I, 23100. No 369335, publd 17 December 1973 (in Russian). ‘3 907. Sealing of a vacuum chamber. (USSR) The vacuum-chamber seal here described differs from existing versions in that on the outer shoulder of the chamber additional flexible strips are provided, together with a spring system which presses them against the parts to be sealed. The springs and strips provide additional sealing forces which come into play, in particular, if the unit as a whole is subjected to varying temperatures or pressures. The ultimate contacts may be either metal (cast iron or bronze) or alternatively asbestos cord. V P Murovtsev and A E Markin, Soviet Patent, class F I6 j. 15/06, No 355423, publd 28 October 1972 (in Russian). 23 908. Inspection window for vacuum chambers. (USSR) A device intended to increase the service life of vacuum installations incorporating screened inspection windows is described. The service life is increased by having the screen fixed rigidly to the vacuum chamber, making the inspection glass movable relative to the screen, and connecting it to the vacuum chamber by means of a flexible hermetic seal. The screen protects the glass from contamination by materials evaporating inside the vacuum chamber except over the small area corresponding to the aperture in the screen. A simple mechanism is therefore provided to move the glass periodically relative to the screen so as to present new, uncontaminated areas to the aperture. In this way the frequency of complete replacements of the inspection window is greatly reduced. V A Pupko and V E Minaichev, Soviet Patent, class C 23 c. l3/08, No 392166, publd I4 December 1973 (in Russian). 909. Demountable vacuum-tight joint. (USSR) An invention designed to improve the efficiency of vacuum ioints subjected to repeated changes of working temperature and pressure is described. The joint is furnished with a cylindrical elastic ‘belt’ connecting a conical projection to one of the parts of the joint, metallic sealing rings also being incorporated. The geometry of the belt and the sealing rings is so adjusted that the combination of elastic forces and thermal expansion called into play as a result of varying temperature and pressures always keeps the contact between the two parts of the joint vacuum-tight. V D Pak and A I Saraev, Soviet Patent, class F I6 j, I S/OS, No 396503, publd I5 January 1974 (in Russian).
24. VALVES ‘4 910. A gas leak. (USSR) A new type of gas-leak construction designed to prevent radial displacements of the gates and valves on heating these in a nonuniform manner above the normal working temperature is proposed. This aim is achieved by incorporating a special guide, engaging with the tail-piece of the gate rod, which is made much longer than that encountered in simpler gas leaks. The gap passing gas into the vessel is regulated by a mechanism based on differential thermal expansion; the gap may thus easily be controlled from a distance by varying the voltage on a small heater unit. 1, N Rozanov and V M Lebedev, Soviet Patenr, class F 16 k. I/04. No 396505, publd I5 January 1974 (in Russian). 288
25. BAFFLES,
TRAPS
AND
REFRIGERATION
EQUIPMEN
‘5 911. A cryogenic vacuum trap. (USSR) A new type of cryogenic trap aimed at protecting the high-vacuum parts of vacuum installations from the deposition of oil vapour emitted by the backing pump is described, its main aim being that of improving operating efficiency and reducing coolant consumption. This is achieved by incorporating an annular Dewar vessel, surrounding the main gas-flow tube and also partly embracing the chamber containing the coolant. The evaporating coolant emerge\ from the Dewar through a specially-shaped gap. In this way the temperature gradient is smodthed gnd undue loss of coolant is avoided. Loss is further reduced bv the use of a specially-designed valve system. I R Kirichek et al, Soviet Patent, class F 04 f; 9106. F 25 d, 3! IO. NC, 398762, publd I2 February I974 (in Russian). 28. HEATING
EQUIPMENT
AND
THERMOMETERS
912. A multiprobe miniature thermistor system for the measurement of temperature profiles. (USA) A new instrument for the determination of fine temperature profiler, in hot. corrosive, electrically conductive, unsteady two-phase fluid systems under vacuum or pressure is described. It features simultaneour measurement of temperatures at close locations, by a column ot miniature (0.25 mm dia) thermistors mounted at the tips of supporting hypodermic tubes, and streamlined design that minimizes hydrodynamic and thermal disturbances at the measured locations. Some of the techniques used in the construction, such as the welding. insulation, and handling of fine wires (0.025 mm dia), are of interest in many other applications. The instrument has been used to measure temoerature distributions with an accuracv of eO.02 C in a model of a flash-evaporator stage used for the desalination of saline water, and thus provided new and quantitatively significant data about the process. N Lior et al, Rev Scient Instrum. 45 (I I ). 1974. 1340--l 343.
III.
Vacuum
30. EVAPORATION
applications AND
SPUTTERING
30 913. Structural dependence of electrical conductivity of thin tellurium films. (USA) Tellurium films were deposited on glass substrates and maintained in vacuum during the course of the measurement of electrical conductivity. The films were found by electron microscopy to have polycrystalline structure with a grain size dependent on deposition parameters. The electrical conductivity increased with increasing thickness. with increasing rate of deposition. and with the transition from the nonannealed to the annealed state. The increase in deposition rate from 100 to 1000 Aimin led to an increase in both grain size and number of surface defects. Annealing resulted in a further increase in grain size but in a decrease in the number of defects. The conductivity could further be explained in terms of mobility and carrielconcentration, the former increasing with increasing grain size and decreasing defects, and the latter increasing with increasing defects. A comparison of quenched and annealed films confirms the dependence of mobility on the number of defects. M A Dinno et al, J Appl Phys. 45 (8), 1974, 3328-333 I. 914. A shadow mask for sputtered films. (USA) Use of a magnet to clamp a magnetic metal mask to the substrate during sputtering resulted in good edge definition in thin film patterns. F W Ingle, Rev Went fnstrum, 45 (1 I ), 1974, 1460-1461, 3(l 915. Nucleus growth rate of vacuum-deposited thin films. (USA) The nucleus growth rate in the initial stages of thin-film formation has been discussed on the basis of the collision theory of a twodimensional gas and the diffusion theory of surface adatoms. It ha\ been shown that, in the formulation of the area of the capture zone. the former theory is suitable for small nuclei (p . 0.27) and the latter for large nuclei (p 0.27), p being the ratio of the nucleus radius to one half of the mean diffusion distance of single adatoms. The foregoing theoretical considerations were examined by the deposition