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A low pressure helium-filled diffusion cloud chamber
Classified abstracts 239--250 method using molecular beams. Determination of sticking coefficient, rate of evaporation and changes in the work function. d. Oxygen desorption from tungsten by electronic bombardment and X-rays. This process has a quantum character with a threshold value of15 eV. e. Thermo-electronic emission from various facets of a tungsten monocrystal coated with barium. f. The evaporation of barium oxide from tungsten and molybdenum substrates. g. Influence of adsorption of oxygen, barium oxide and barium on the Hall effect in thin nickel films. h, Application of slow electron diffraction method to the study of monatomic film structure of barium on (110) tungsten. 2. Thermo electronic emission and the thermoelectronic energy converter. 3. Secondary electron and photoelectronic emission. 4. Auto electronic emission. 5. Interaction of solid surfaces with heavy particles (atoms, molecules and ions). Anon, Radiotechnics & Electronics, (6), 1964, 1099-1113 (in
Russian). 18:64 239. Investigation into electrical discharges in gases. B N Klyarfeld, Translated from the Russian by D Cossulta, Pergamon Press, Oxford, 1964. 18 240. Some characteristics of an electrodeless ring discharge. (USSR) The experiments were carried out in air and nitrogen at pressures from 0.05 torr to 0.9 torr. Over this range, the electron density on the axis increased from 2.5 × 101°/cm a to 4.1 x 10~/cm a with electron temperatures of 5 eV at the higher pressure. A D Andreev and Yu N Lobanov, Zh Tekh Fiz, 34 (10), Oct 1964, 1863-1866 (in Russian). 18 241. Instabilities in Penning discharges. (USA) The generation of oscillations in the microwave region in a cold cathode Penning discharge at a gas pressure of a few microns was studied. The measurements indicate that slow electromagnetic waves with a phase velocity roughly equal to the velocity of electrons accelerated by the potential drop anode-cathode are supported by the discharge. B Agour and V Ternstrom, Phys Rev Letters, 13 ([), 1964, 5-7. 18 242. A low pressure helium-filled diffusion cloud chamber. (Turkey) Satisfactory working conditions were obtained at pressures as low as 50 tort, the temperatures of the sensitive region varying from 5 ° to --17°C with clearing fields ranging from 2000 to 350 V. The polarity of this field had a marked effect, a negative field yielding thecleaner =tracks. (Turkey) S Barkan, Rev Fac Sci Univ lstanbul, 29, (1-2), 1964, 1-12. 18:40 243. The influence of metastable molecules on static breakdown in nitrogen at low pressures. (Germany) At low pressures the discharge current consists of two components, one of which (the so-called fast process) arises from secondary electrons whilst the other or slower process is due to the decay of a metastable state. H Kriseh, Z NatuJforsch, 19a (9), 1964, 1136-[137.
19. Radiation 19 Spectroscopic studies of "weak" and "strong" high frequency discharges in the inert gases He, Ne and Ar. See abstract number 236. 19 Note on glow discharge technique for Se, As and other vapours. See abstract number 237. 19 Measurement of the thickness of thin films by optical means, from Rayleigh and Drude to Langmuir and the development of the present eilipsometer. See abstract number 287, 19 Ellipsometry in the measurement of surfaces and thin films symposium. See abstract number 288. 19 Investigation on the composition of the residual gas in instruments 160
fitted with muitilayer photocathodes. See abstract number 304. 19 : 30 244. Application of eilipsometry to the study of phenomena on surfaces prepared in ultrahigh vacuum. (USA) Ellipsometric observations were carried out on evaporated films kept at 10-9 torr. Changes in optical properties immediately after deposition generally indicate loss of surface material at room temperature. In the case of aluminium however there is evidence after about 4 hours of growth of a surface film 10 A, thick. J F Deltorre et al, Misc Publ Nat Bur Stand, 256, 1964, 245-254. 19 : 16 245. Application of ellipsometry to the study of adsorption from solutions. (USA) Polystyrenes with molecular weight ranging from approximately 70,000 to 500,000 were adsorbed from a cyclohexane solution (0.2 mg/ml) on to a chrome surface, the thickness and refractive index of the resultant deposit being measured by ellipsometry. Film thickness ranged from 200 to 500 A, increasing with the molecular weight of the styrene. R R Stromberg et al, Misc Publ Nat Bur Stand, 256, 1964, 281-296. 19 : 16 : 33 246. Measurement of the physical adsorption of vapours and the chemisorption of oxygen on silicon by the method of ellipsometry.
(USA.) The monolayer of chemisorbed oxygen on clean silicon has a thickness Of 2.5 --2.8 A. The sticking coefficient was found to be independent of the pressure over tha range 7 ;< l0 -s to 1 x l0 ~ torr and the average value of 6 >: 10 a is independent of coverage up to 60-70 per cent. R J Archer, Misc Publ Nat Bur Stand, 256, 1964, 255-279. 19 247, Thermoluminesceuce of inorganic compounds at low pressures.
(Italy) Unlike the response of irradiated organic compounds, thermoluminescence of inorganic material is a surface phenomenon and disappears if the ambient pressure is reduced to below 10-3 torr. C Beltinali and G Ferraresso, R C Acad Naz Lintel, 35 (6), 1963,
555-557. 19 : 16 248. Radiation enhanced diffusion in metals. (USA) Diffusion in metals takes place mainly via vacancies and low temperature diffusion can be increased if vacancies are produced artiticially, e.g. as a result of radiation damage. In this way the lowest free energy state of an alloy can be produced at temperatures where this had been impossible previously. Thus the equilibrium state of a brass is reached in a few hours of irradiation by electrons. A C Damask, Radiation Damage in Solids, Academic Press, 1962, 763-776. 19 249. Method of determining the optical constants and thickness of semi-transparent films. Application to multilayer photocathodes. (USSR) The author shows how from a knowledge of the optical coefficients of transmission and reflection by the film, supplemented by the coefficient of reflection of the substrate, it is possible to deduce the refractive index and thickness of the film. The method can be applied to parallel as well as wedge-shaped films, and can be used under conditions precluding phase difference measurements. V E Kondoashev and A S Shefov, Izv A N SSR Ser Fiz, 28 (9), 1964, 1444-1449 (in Russian). 19 : 30 : 4l 250. Optical eoetfieients of thin chromium films obtained by thermal evaporation in vacuum. (USSR) Films obtained by sublimation on a previously heated substrate without the use of a shield contain a large amount of adsorbed gas and are termed "less" metallic by the author. If a mask is used or if the substrate is efficiently degassed before deposition, " m o r e " metallic films result. For these two groups of films the author measured the following optical coefficients: Reflection from air side R; reflection from substrate R'; transmission T. Measurements were also carried out over a range of wavelengths from 4000 to 10,000 & using a Zeiss spectrophotometer. Film thickness ranged from 100 to 1000 ~ . It was determined by interferometry with an accuracy of --5 per cent. The following conclusions were drawn: (1) The optical properties of chromium films depend on sublimation conditions. If gas adsorption is reduced, the reflection coefficient
Russian). 18:64 239. Investigation into electrical discharges in gases. B N Klyarfeld, Translated from the Russian by D Cossulta, Pergamon Press, Oxford, 1964. 18 240. Some characteristics of an electrodeless ring discharge. (USSR) The experiments were carried out in air and nitrogen at pressures from 0.05 torr to 0.9 torr. Over this range, the electron density on the axis increased from 2.5 × 101°/cm a to 4.1 x 10~/cm a with electron temperatures of 5 eV at the higher pressure. A D Andreev and Yu N Lobanov, Zh Tekh Fiz, 34 (10), Oct 1964, 1863-1866 (in Russian). 18 241. Instabilities in Penning discharges. (USA) The generation of oscillations in the microwave region in a cold cathode Penning discharge at a gas pressure of a few microns was studied. The measurements indicate that slow electromagnetic waves with a phase velocity roughly equal to the velocity of electrons accelerated by the potential drop anode-cathode are supported by the discharge. B Agour and V Ternstrom, Phys Rev Letters, 13 ([), 1964, 5-7. 18 242. A low pressure helium-filled diffusion cloud chamber. (Turkey) Satisfactory working conditions were obtained at pressures as low as 50 tort, the temperatures of the sensitive region varying from 5 ° to --17°C with clearing fields ranging from 2000 to 350 V. The polarity of this field had a marked effect, a negative field yielding thecleaner =tracks. (Turkey) S Barkan, Rev Fac Sci Univ lstanbul, 29, (1-2), 1964, 1-12. 18:40 243. The influence of metastable molecules on static breakdown in nitrogen at low pressures. (Germany) At low pressures the discharge current consists of two components, one of which (the so-called fast process) arises from secondary electrons whilst the other or slower process is due to the decay of a metastable state. H Kriseh, Z NatuJforsch, 19a (9), 1964, 1136-[137.
19. Radiation 19 Spectroscopic studies of "weak" and "strong" high frequency discharges in the inert gases He, Ne and Ar. See abstract number 236. 19 Note on glow discharge technique for Se, As and other vapours. See abstract number 237. 19 Measurement of the thickness of thin films by optical means, from Rayleigh and Drude to Langmuir and the development of the present eilipsometer. See abstract number 287, 19 Ellipsometry in the measurement of surfaces and thin films symposium. See abstract number 288. 19 Investigation on the composition of the residual gas in instruments 160
fitted with muitilayer photocathodes. See abstract number 304. 19 : 30 244. Application of eilipsometry to the study of phenomena on surfaces prepared in ultrahigh vacuum. (USA) Ellipsometric observations were carried out on evaporated films kept at 10-9 torr. Changes in optical properties immediately after deposition generally indicate loss of surface material at room temperature. In the case of aluminium however there is evidence after about 4 hours of growth of a surface film 10 A, thick. J F Deltorre et al, Misc Publ Nat Bur Stand, 256, 1964, 245-254. 19 : 16 245. Application of ellipsometry to the study of adsorption from solutions. (USA) Polystyrenes with molecular weight ranging from approximately 70,000 to 500,000 were adsorbed from a cyclohexane solution (0.2 mg/ml) on to a chrome surface, the thickness and refractive index of the resultant deposit being measured by ellipsometry. Film thickness ranged from 200 to 500 A, increasing with the molecular weight of the styrene. R R Stromberg et al, Misc Publ Nat Bur Stand, 256, 1964, 281-296. 19 : 16 : 33 246. Measurement of the physical adsorption of vapours and the chemisorption of oxygen on silicon by the method of ellipsometry.
(USA.) The monolayer of chemisorbed oxygen on clean silicon has a thickness Of 2.5 --2.8 A. The sticking coefficient was found to be independent of the pressure over tha range 7 ;< l0 -s to 1 x l0 ~ torr and the average value of 6 >: 10 a is independent of coverage up to 60-70 per cent. R J Archer, Misc Publ Nat Bur Stand, 256, 1964, 255-279. 19 247, Thermoluminesceuce of inorganic compounds at low pressures.
(Italy) Unlike the response of irradiated organic compounds, thermoluminescence of inorganic material is a surface phenomenon and disappears if the ambient pressure is reduced to below 10-3 torr. C Beltinali and G Ferraresso, R C Acad Naz Lintel, 35 (6), 1963,
555-557. 19 : 16 248. Radiation enhanced diffusion in metals. (USA) Diffusion in metals takes place mainly via vacancies and low temperature diffusion can be increased if vacancies are produced artiticially, e.g. as a result of radiation damage. In this way the lowest free energy state of an alloy can be produced at temperatures where this had been impossible previously. Thus the equilibrium state of a brass is reached in a few hours of irradiation by electrons. A C Damask, Radiation Damage in Solids, Academic Press, 1962, 763-776. 19 249. Method of determining the optical constants and thickness of semi-transparent films. Application to multilayer photocathodes. (USSR) The author shows how from a knowledge of the optical coefficients of transmission and reflection by the film, supplemented by the coefficient of reflection of the substrate, it is possible to deduce the refractive index and thickness of the film. The method can be applied to parallel as well as wedge-shaped films, and can be used under conditions precluding phase difference measurements. V E Kondoashev and A S Shefov, Izv A N SSR Ser Fiz, 28 (9), 1964, 1444-1449 (in Russian). 19 : 30 : 4l 250. Optical eoetfieients of thin chromium films obtained by thermal evaporation in vacuum. (USSR) Films obtained by sublimation on a previously heated substrate without the use of a shield contain a large amount of adsorbed gas and are termed "less" metallic by the author. If a mask is used or if the substrate is efficiently degassed before deposition, " m o r e " metallic films result. For these two groups of films the author measured the following optical coefficients: Reflection from air side R; reflection from substrate R'; transmission T. Measurements were also carried out over a range of wavelengths from 4000 to 10,000 & using a Zeiss spectrophotometer. Film thickness ranged from 100 to 1000 ~ . It was determined by interferometry with an accuracy of --5 per cent. The following conclusions were drawn: (1) The optical properties of chromium films depend on sublimation conditions. If gas adsorption is reduced, the reflection coefficient