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1767. Mass composition of high energy ions bomabarding the cathode in an anomalous glow discharge
Classified
abstracts
1758-1769
1758. Thermal conductivity of binary mixtures of ammonia and inert gases. (Great Britain)
The thermal conductivities of binary mixtures of NH,-Ar, NH,-Ne and NH,-He have been measured over the temperature range 39199°C for various compositions. The observed values are found to vary non-linearly with composition at all temperatures. B N Srivastava and A Das Gupta, Brit J Appl, Phys, 18 (7), July 1967, 945-951.
18. GASEOUS
ELECTRONICS
18 : 32 Plasma sources of ions of high-melting point materials. See abstract number 1868. 18 :64 1759. Session of Scientific Council on Physical Electronics. (USSR) Abstracts are given of papers presented at a Session organized by the Scientific Council on Physical Electronics of the Soviet Academy of Sciences in October 1966. This session dealt with photoemission properties of semiconducting materials, investigations of effective photocathodes, field emission and properties of some thin film systems. A L Musatov et al, Radiotekh Elektron, 12 (6), June 1967, 1138-l 142 (in Russian) 18 1760. Electrical breakdown and discharge in vacuum. (USSR) Basic physical principles and experimental data are given in this well-prepared monograph containing the influence of different types of emission on initiating discharges, the influence of a strong electric field on electrode surface microstructure, pre-breakdown stages and self-interrupted microdischarges, dc, pulse and hf high voltage breakdowns (including the multipacticm effect), effects during arcing and low-pressure discharges in the left branch of the Paschen curve. Different theories explaining the mechanism of vacuum breakdown are discussed in detail. I N Slivkov et al, bookpubl’d by Atomizdat, Moscow, 1966,3OOpages, price 1.30 Rb raz-ryad).
(in Russian--original
title:
Elektricheskiy
proboy
1761. Studies relevant to the electric vacuum gyro programme electrical breakdown in ultrahigh vacuum. (USA)
i 18 of
Experimental measurements were made to determine the effect of gas-conditioning in suppressing field emission current and improving the voltage holding capacity of plane tungsten electrodes in ultrahigh vacuum. Apparatus was constructed and experiments were conducted to study the work function of portions of a tungsten emitter tip exhibiting the flicker effect in field emission. Experiments were performed to study the formation mechanism of metallic protuberances or whiskers on the cathode which cause electrical breakdown in ultrahigh vacuum. E M Lyman, Rep NASA-CR-82954; R-334, January 1967 (Illinois &iv,
Urbana, Coordinated
Science Lab). 18
1762. Pulsed flashover in vacuum
(USA) Experiments on vacuum flashover of dielectric frusta subjected to 35 and 75 nsec pulses were carried out in a test chamber with capacitive voltage grading along its 12 inch length due to alternating glass disk and metal ring construction, pumped at pressures between 5 x 1O-Band 1O-5 torr. A theory is presented to explain the formative process leading to flashover. It is proposed that the positive surface charge grows by emission of hot electrons during the application of the electric field, which then multiply by secondary emission until the critical breakdown condition is achieved. The experimental data are analyzed and interpreted in the light of this theory. A Watson. d Appl Phys, 38 (5), 1967, 2019-2023. 1763. The constricted positive discharge in alkali-metal-seeded
column of a non-equilibrium rare gases. (Great Britain)
18 electric
Measurements were carried out on discharges between plane circular electrodes immersed in rare gases (helium, argon at 1 atm) seeded with sodium, potassium, cesium at pressures between 7x 1OW and 40 torr. The electrode voltage is plotted against electrode spacing (l-30 mm) for different currents, temperatures and seed pressures. From the slopes and voltage intercepts of these graphs, the positive column electric field and electrode voltage drop values were obtained.
The energy balance of the column is discussed, and the fall in electric field with rising current is explained in terms of the heat losses at the column boundary. The gas temperature of the column is discussed and is shown to be higher than the temperature outside the column and to rise as the column axis is approached. The axis temperature is shown to rise as the current increases. H I Ellington, Brit J Appl Phys, 18 (7), July 1967, 931-937. 18 1764. Mass-spectrometer analysis of the glow discharge fast channel ions in binary gas mixtures. (USSR)
Using an MS-4 mass-spectrometer the glow discharge fast channel ions were analyzed. Ions of the electrode material were strongly indicated in all gas mixtures and, with 80 per cent Ar + 20 per cent Ne mixture, Al+ ions were almost twice as strong as Ar+ ions. In all Ar + Ne mixtures no Ne+ ions were found and in Ar + N, mixtures the most strongly registered ions were N+. In Ar + 0, mixtures 90 to 95 per cent of all ions were O+ and O,+ and in Nz + 0, mixtures NO+ ion was the major component. The efficiency of ion charge exchange in the cathode dark space is briefly discussed. R M Bashirova, Izv VUZ Fiz, 10 (5), 1967, 99-103 (in Russian). 18 1765. Positive column of a low-pressure discharge in a toroidal tube.
(Czechoslovakia) Expressions are derived for the radial course of ions, the radial component of the electric field and equipotentials in the positive column of a glow discharge in a toroidal tube. P Kocian, Czech J Phys, B 17 (7), 1967, ,632-635 (in English). 18 1766. Longitudinal separation of a gas mixture in a glow discharge.
(USSR) Druyvesteyn’s theory on longitudinal separation of a gas mixture in a glow discharge positive column is extended to the case of a longitudinal heterogeneous column and also the transversal gas mixture separation is take> into account. Yu A Pekar, Zh Tekh Fiz, 37 (6), June 1967, 1112-1117 (in Russian). 18 1767. Mass composition of high energy ions bombarding the cathode in an anomalous glow discharge. (USSR) In air, 95 per cent 0, + 5 per cent N, and 98 per cent N, + 2 per cent O2 mixtures at pressure of 0.1 to 0.3 torr, glow discharges at voltages of 2 to 3 kV and currents of 5 to 80 mA were investigated. Through an orifice in the cathode, fast channel ions were led to an MS4 mass spectrometer. Excluding ions of the cathode material, all filling gas components were detected but with very different proportions. This effect is explained by ion charge exchange in the cathode dark space. A V Bondarenko and M A Lebedev, Zh Tekh Fiz, 37 (6), June 1967, 1074-1078 (in Russian). 1768. Effect of ac amplitude on the measurement distribution functions. (Great Britain)
18 of electron energy
The energy distribution function of the electrons in the positive column of a glow discharge in spectroscopically pure nitrogen at a pressure of 0.1 torr has been determined. The work was carried out in a vacuum system entirely bakeable at 45o”C, in order to reach a pressure of lo-’ torr before the pure nitrogen is admitted. The construction of the discharge tube and probes used are discussed. The measurement involved determination of the second-harmonic component of the current in a Langmuir probe circuit when an ac signal is superimposed on the dc bias applied to the probe. The effect on the apparent form of the electron energy distribution function of varying the amplitude of the ac signal is discussed and it is shown that the use of amplitudes exceeding 0.1 V can result in serious errors. A I Kilvington et al, J Sci Znstrum, 44 (7), July 1967, 517-520. 18 1769. The absolute average energy to form ion pairs in gases. (Germany) The absolute average ionization energy necessary to form an ion pair in air, 02, N,, COz and Ar was determined for H3 beta-particles. The energy was determined from the maximal ion current for each gas and the known shape of the energy distribution curve. The results are in good agreement with values published for alpha-particles in argon. H Buktas, Z Angew Phys, 23 (2), July 1967, 74-77 (in German) 615
abstracts
1758-1769
1758. Thermal conductivity of binary mixtures of ammonia and inert gases. (Great Britain)
The thermal conductivities of binary mixtures of NH,-Ar, NH,-Ne and NH,-He have been measured over the temperature range 39199°C for various compositions. The observed values are found to vary non-linearly with composition at all temperatures. B N Srivastava and A Das Gupta, Brit J Appl, Phys, 18 (7), July 1967, 945-951.
18. GASEOUS
ELECTRONICS
18 : 32 Plasma sources of ions of high-melting point materials. See abstract number 1868. 18 :64 1759. Session of Scientific Council on Physical Electronics. (USSR) Abstracts are given of papers presented at a Session organized by the Scientific Council on Physical Electronics of the Soviet Academy of Sciences in October 1966. This session dealt with photoemission properties of semiconducting materials, investigations of effective photocathodes, field emission and properties of some thin film systems. A L Musatov et al, Radiotekh Elektron, 12 (6), June 1967, 1138-l 142 (in Russian) 18 1760. Electrical breakdown and discharge in vacuum. (USSR) Basic physical principles and experimental data are given in this well-prepared monograph containing the influence of different types of emission on initiating discharges, the influence of a strong electric field on electrode surface microstructure, pre-breakdown stages and self-interrupted microdischarges, dc, pulse and hf high voltage breakdowns (including the multipacticm effect), effects during arcing and low-pressure discharges in the left branch of the Paschen curve. Different theories explaining the mechanism of vacuum breakdown are discussed in detail. I N Slivkov et al, bookpubl’d by Atomizdat, Moscow, 1966,3OOpages, price 1.30 Rb raz-ryad).
(in Russian--original
title:
Elektricheskiy
proboy
1761. Studies relevant to the electric vacuum gyro programme electrical breakdown in ultrahigh vacuum. (USA)
i 18 of
Experimental measurements were made to determine the effect of gas-conditioning in suppressing field emission current and improving the voltage holding capacity of plane tungsten electrodes in ultrahigh vacuum. Apparatus was constructed and experiments were conducted to study the work function of portions of a tungsten emitter tip exhibiting the flicker effect in field emission. Experiments were performed to study the formation mechanism of metallic protuberances or whiskers on the cathode which cause electrical breakdown in ultrahigh vacuum. E M Lyman, Rep NASA-CR-82954; R-334, January 1967 (Illinois &iv,
Urbana, Coordinated
Science Lab). 18
1762. Pulsed flashover in vacuum
(USA) Experiments on vacuum flashover of dielectric frusta subjected to 35 and 75 nsec pulses were carried out in a test chamber with capacitive voltage grading along its 12 inch length due to alternating glass disk and metal ring construction, pumped at pressures between 5 x 1O-Band 1O-5 torr. A theory is presented to explain the formative process leading to flashover. It is proposed that the positive surface charge grows by emission of hot electrons during the application of the electric field, which then multiply by secondary emission until the critical breakdown condition is achieved. The experimental data are analyzed and interpreted in the light of this theory. A Watson. d Appl Phys, 38 (5), 1967, 2019-2023. 1763. The constricted positive discharge in alkali-metal-seeded
column of a non-equilibrium rare gases. (Great Britain)
18 electric
Measurements were carried out on discharges between plane circular electrodes immersed in rare gases (helium, argon at 1 atm) seeded with sodium, potassium, cesium at pressures between 7x 1OW and 40 torr. The electrode voltage is plotted against electrode spacing (l-30 mm) for different currents, temperatures and seed pressures. From the slopes and voltage intercepts of these graphs, the positive column electric field and electrode voltage drop values were obtained.
The energy balance of the column is discussed, and the fall in electric field with rising current is explained in terms of the heat losses at the column boundary. The gas temperature of the column is discussed and is shown to be higher than the temperature outside the column and to rise as the column axis is approached. The axis temperature is shown to rise as the current increases. H I Ellington, Brit J Appl Phys, 18 (7), July 1967, 931-937. 18 1764. Mass-spectrometer analysis of the glow discharge fast channel ions in binary gas mixtures. (USSR)
Using an MS-4 mass-spectrometer the glow discharge fast channel ions were analyzed. Ions of the electrode material were strongly indicated in all gas mixtures and, with 80 per cent Ar + 20 per cent Ne mixture, Al+ ions were almost twice as strong as Ar+ ions. In all Ar + Ne mixtures no Ne+ ions were found and in Ar + N, mixtures the most strongly registered ions were N+. In Ar + 0, mixtures 90 to 95 per cent of all ions were O+ and O,+ and in Nz + 0, mixtures NO+ ion was the major component. The efficiency of ion charge exchange in the cathode dark space is briefly discussed. R M Bashirova, Izv VUZ Fiz, 10 (5), 1967, 99-103 (in Russian). 18 1765. Positive column of a low-pressure discharge in a toroidal tube.
(Czechoslovakia) Expressions are derived for the radial course of ions, the radial component of the electric field and equipotentials in the positive column of a glow discharge in a toroidal tube. P Kocian, Czech J Phys, B 17 (7), 1967, ,632-635 (in English). 18 1766. Longitudinal separation of a gas mixture in a glow discharge.
(USSR) Druyvesteyn’s theory on longitudinal separation of a gas mixture in a glow discharge positive column is extended to the case of a longitudinal heterogeneous column and also the transversal gas mixture separation is take> into account. Yu A Pekar, Zh Tekh Fiz, 37 (6), June 1967, 1112-1117 (in Russian). 18 1767. Mass composition of high energy ions bombarding the cathode in an anomalous glow discharge. (USSR) In air, 95 per cent 0, + 5 per cent N, and 98 per cent N, + 2 per cent O2 mixtures at pressure of 0.1 to 0.3 torr, glow discharges at voltages of 2 to 3 kV and currents of 5 to 80 mA were investigated. Through an orifice in the cathode, fast channel ions were led to an MS4 mass spectrometer. Excluding ions of the cathode material, all filling gas components were detected but with very different proportions. This effect is explained by ion charge exchange in the cathode dark space. A V Bondarenko and M A Lebedev, Zh Tekh Fiz, 37 (6), June 1967, 1074-1078 (in Russian). 1768. Effect of ac amplitude on the measurement distribution functions. (Great Britain)
18 of electron energy
The energy distribution function of the electrons in the positive column of a glow discharge in spectroscopically pure nitrogen at a pressure of 0.1 torr has been determined. The work was carried out in a vacuum system entirely bakeable at 45o”C, in order to reach a pressure of lo-’ torr before the pure nitrogen is admitted. The construction of the discharge tube and probes used are discussed. The measurement involved determination of the second-harmonic component of the current in a Langmuir probe circuit when an ac signal is superimposed on the dc bias applied to the probe. The effect on the apparent form of the electron energy distribution function of varying the amplitude of the ac signal is discussed and it is shown that the use of amplitudes exceeding 0.1 V can result in serious errors. A I Kilvington et al, J Sci Znstrum, 44 (7), July 1967, 517-520. 18 1769. The absolute average energy to form ion pairs in gases. (Germany) The absolute average ionization energy necessary to form an ion pair in air, 02, N,, COz and Ar was determined for H3 beta-particles. The energy was determined from the maximal ion current for each gas and the known shape of the energy distribution curve. The results are in good agreement with values published for alpha-particles in argon. H Buktas, Z Angew Phys, 23 (2), July 1967, 74-77 (in German) 615