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443. The magnetic triode
Classified Abstracts 442--453 quantity of water vapour absorbed in or desorbed from different oxide coatings under defined conditions has been determined by means of a mass spectrometer. The difference between SiO2 and A1203 on the one hand and MgO on the other is specially emphasized. Finally, the getter action of several freshly condensed oxide films is examined. (in German) (Authors)
161
faction of the helium is carried by expansion accompanied by external work. No precooling with liquid hydrogen is defined. The installation has been designed to work for long periods, maintaining a temperature between 3 and 4 °K to within 0.05 °K. W . J . S.
Anon., New Scientist, 17 (325), 7 Feb. 1963, 277.
W. Reichelt and P. Miiller, Vakuum-Technik, 11 (8), Dec. 1962, 325-239. 30 : 56 442. Dielectric properties and breakdown of very thin film capacitors. Great Britain. Most of the experiments described by the author were carried out on silicon monoxide. Capacity and resistance measurements were made at 1500 cycles, the thickness of the films being of the order of 600/~. Currents were measured over a range of voltage up to breakdown. F r o m the general characteristics of these curves it appears that there are a number of sources of carriers which can be activated by access to the atmosphere and which disappear when the film is treated in vacuo. Carefully evaporated films well protected from the atmosphere have a very high breakdown strength--approaching that of mica. Much more work will be necessary before thin films can be produced in quantity with consistent characteristics. In the authors opinion it is premature to assign limiting values, so much depending on the method of preparation as well as testing, w.s.s. J. B. Bruce, Le Vide, 17 (99), May/June 1962, 244-249.
31.
E v a c u a t i o n and S e a l i n g
31 : 56 443. The magnetic triode. Great Britain. This article discusses the problems in the design of thermoelectric devices for the direct conversion of heat to electricity. These are basically diodes in which the work function of the anode material is lower than that of the cathode material, the difference providing the output voltage. The major problem to be overcome is that of the space charge ; a frequently-used technique is to introduce the vapour of an alkali metal which will ionize by contact with the hot cathode. In the method introduced in the article, an accelerating electrode, parallel to the cathode, is used, with a transverse magnetic field to divert the electrons to a collector plate mounted alongside the cathode. The problems which arise owing to electrons acquiring kinetic energy from the accelerator supply are the main subject of the article. This arises owing to instabilities in the space cloud in the presence of the magnetic field. G. F. Harris, et. al., Electron. Tech. 39, Jan. 1962, 27-30. 32.
Nucleonics
32 444. The preparation of thin films of V Y N S resin for 4~- beta counting. Great Britain. A method is described of spreading a 3 per cent solution of the plastic in ethylene dichloride on the surface of clean mercury. Evaporation is rapid. The film is trimmed to size by use of a sharp scalpel and peeled off. The thickness of the films is varied by alteration of quantity of solution or concentration. Superficial densities vary between 1 and 50/~g cm -2. W . J . S.
J. K. Johanneson, J. Sci. Instrum., 37 (7), July 1962, 390-391. 32 : 58 : 40 445. Helium bubble chamber. Great Britain. The National Institute of Research in Nuclear Science (N.I.R.N.S.) at Chilton in Berkshire is building a 200 1. helium bubble chamber to be used in conjunction with the 7 GeV proton synchroton 12 Nimrod under construction. The ligne-
The hot-wire triggered spark gap at very high voltages. Abstr. No. 302.
33.
32 See
G e n e r a l P h y s i c s and E l e c t r o n i c s
33 : 37 446. Glow discharge as a heat source for surface and floating zone melting. Czechoslovakia. A method of heating, making use of the thermal effect on a glow discharge cathode for surface and floating zone melting, is described. (Author) Z. Trousil, Czech. J. Phys., BI2 (3), March 1962, 227-231. 33 : 56 447. A survey of R.F. heating valves. P. G. Simpson, Brit. Commun. & Electron., 9, May/June 1962, 340-7 ; 440-5. 33 448. Determination of the origin of the image contrast in the electron mirror microscope. (In German). J. Heydenreich, Exp. Tech. derPhys., 10 (5), 1962, 346-354. 33
449. Holey film for electron microscopy. W. J. Harris, Nature, Lond., 196 (4853), Nov. 3, 1962, 499-500. 33 450. Design aspects of the hot stage for E.M.V.3 series electron microscopes. A. J. Cardile and J. W. Coleman, R.C.A. Sci. Instrum. News, 7 (2), Aug. 1962, 11-15. 33 451. Preparing carbon film nets (for electron microscope astigmatism study). J. J. Byrd, R.C.,4. Sci. Instrum. News, 7 (2), Aug. 1962, 20. 33 452. Vacuum X-ray diffractometer for high temperature studies of metals sensitive to contamination by oxygen and nitroKen. U.S.A. An X-ray diffractometer operating in vacuum has been designed and constructed to study metals sensitive to oxygen and nitrogen contamination at elevated temperature. The instrument operates in a vacuum of 2 × 10-6 tort in which the partial pressure of oxygen and nitrogen is several orders of magnitude lower than the total pressure. The specimen is heated by radiation from a resistance-type furnace to 1200°C. With this instrument it is possible to obtain lattice parameters which are accurate to one part in forty thousand. The thermal expansion of titanium has been investigated up to 650°C. Between room temperature and 400°C the expansion coefficients in directions perpendicular and parallel to the c axis are 9.41 × 10 -e and 11.18 × 10 -6 respectively. For a random polycrystalline sample the mean expansion coefficient is 10.0 × 10-n/°C. (Author) R. H. Willens, Rev. Sci. Instrum., 33 (10), Oct. 1962, 1069-1076. 33 453. Temperature distribution and its changes in a solid bombarded by a beam of charged particles. Japan. To obtain information regarding the effects of beam
161
faction of the helium is carried by expansion accompanied by external work. No precooling with liquid hydrogen is defined. The installation has been designed to work for long periods, maintaining a temperature between 3 and 4 °K to within 0.05 °K. W . J . S.
Anon., New Scientist, 17 (325), 7 Feb. 1963, 277.
W. Reichelt and P. Miiller, Vakuum-Technik, 11 (8), Dec. 1962, 325-239. 30 : 56 442. Dielectric properties and breakdown of very thin film capacitors. Great Britain. Most of the experiments described by the author were carried out on silicon monoxide. Capacity and resistance measurements were made at 1500 cycles, the thickness of the films being of the order of 600/~. Currents were measured over a range of voltage up to breakdown. F r o m the general characteristics of these curves it appears that there are a number of sources of carriers which can be activated by access to the atmosphere and which disappear when the film is treated in vacuo. Carefully evaporated films well protected from the atmosphere have a very high breakdown strength--approaching that of mica. Much more work will be necessary before thin films can be produced in quantity with consistent characteristics. In the authors opinion it is premature to assign limiting values, so much depending on the method of preparation as well as testing, w.s.s. J. B. Bruce, Le Vide, 17 (99), May/June 1962, 244-249.
31.
E v a c u a t i o n and S e a l i n g
31 : 56 443. The magnetic triode. Great Britain. This article discusses the problems in the design of thermoelectric devices for the direct conversion of heat to electricity. These are basically diodes in which the work function of the anode material is lower than that of the cathode material, the difference providing the output voltage. The major problem to be overcome is that of the space charge ; a frequently-used technique is to introduce the vapour of an alkali metal which will ionize by contact with the hot cathode. In the method introduced in the article, an accelerating electrode, parallel to the cathode, is used, with a transverse magnetic field to divert the electrons to a collector plate mounted alongside the cathode. The problems which arise owing to electrons acquiring kinetic energy from the accelerator supply are the main subject of the article. This arises owing to instabilities in the space cloud in the presence of the magnetic field. G. F. Harris, et. al., Electron. Tech. 39, Jan. 1962, 27-30. 32.
Nucleonics
32 444. The preparation of thin films of V Y N S resin for 4~- beta counting. Great Britain. A method is described of spreading a 3 per cent solution of the plastic in ethylene dichloride on the surface of clean mercury. Evaporation is rapid. The film is trimmed to size by use of a sharp scalpel and peeled off. The thickness of the films is varied by alteration of quantity of solution or concentration. Superficial densities vary between 1 and 50/~g cm -2. W . J . S.
J. K. Johanneson, J. Sci. Instrum., 37 (7), July 1962, 390-391. 32 : 58 : 40 445. Helium bubble chamber. Great Britain. The National Institute of Research in Nuclear Science (N.I.R.N.S.) at Chilton in Berkshire is building a 200 1. helium bubble chamber to be used in conjunction with the 7 GeV proton synchroton 12 Nimrod under construction. The ligne-
The hot-wire triggered spark gap at very high voltages. Abstr. No. 302.
33.
32 See
G e n e r a l P h y s i c s and E l e c t r o n i c s
33 : 37 446. Glow discharge as a heat source for surface and floating zone melting. Czechoslovakia. A method of heating, making use of the thermal effect on a glow discharge cathode for surface and floating zone melting, is described. (Author) Z. Trousil, Czech. J. Phys., BI2 (3), March 1962, 227-231. 33 : 56 447. A survey of R.F. heating valves. P. G. Simpson, Brit. Commun. & Electron., 9, May/June 1962, 340-7 ; 440-5. 33 448. Determination of the origin of the image contrast in the electron mirror microscope. (In German). J. Heydenreich, Exp. Tech. derPhys., 10 (5), 1962, 346-354. 33
449. Holey film for electron microscopy. W. J. Harris, Nature, Lond., 196 (4853), Nov. 3, 1962, 499-500. 33 450. Design aspects of the hot stage for E.M.V.3 series electron microscopes. A. J. Cardile and J. W. Coleman, R.C.A. Sci. Instrum. News, 7 (2), Aug. 1962, 11-15. 33 451. Preparing carbon film nets (for electron microscope astigmatism study). J. J. Byrd, R.C.,4. Sci. Instrum. News, 7 (2), Aug. 1962, 20. 33 452. Vacuum X-ray diffractometer for high temperature studies of metals sensitive to contamination by oxygen and nitroKen. U.S.A. An X-ray diffractometer operating in vacuum has been designed and constructed to study metals sensitive to oxygen and nitrogen contamination at elevated temperature. The instrument operates in a vacuum of 2 × 10-6 tort in which the partial pressure of oxygen and nitrogen is several orders of magnitude lower than the total pressure. The specimen is heated by radiation from a resistance-type furnace to 1200°C. With this instrument it is possible to obtain lattice parameters which are accurate to one part in forty thousand. The thermal expansion of titanium has been investigated up to 650°C. Between room temperature and 400°C the expansion coefficients in directions perpendicular and parallel to the c axis are 9.41 × 10 -e and 11.18 × 10 -6 respectively. For a random polycrystalline sample the mean expansion coefficient is 10.0 × 10-n/°C. (Author) R. H. Willens, Rev. Sci. Instrum., 33 (10), Oct. 1962, 1069-1076. 33 453. Temperature distribution and its changes in a solid bombarded by a beam of charged particles. Japan. To obtain information regarding the effects of beam