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The theory of the production of intense ions beams in the relativistic diode
Classified
abstracts
3 1. EVACUATION
1085-l
098
AND SEALING 31:33
1085. On removing graphite dust from (electrical) parts. (USSR) A method of removing graphite dust from electrical components (likely to prove of particular value in the electronics industry and other fields using electrical vacuum apparatus) is described. To this end the parts in question are briefly immersed in liquified gases (helium, neon, argon, etc.). If the parts are very large they may alternatively be sprayed with these liquids. The removal of graphite from deep pores is further eased by heating the parts to lOO-170°C before immersion in the cryogenic liquid, so increasing the sudden temperature drop. G M Bntyrin, Soviet Patent, class H 01 j, 9102, No 391638, claimed 18 August 1971, publd 3 December 1973 (in Russian). 31 1086. Perveance and structure of electron beam in a diode with point cathode operated in the mode of explosive electron emission. (USSR) Current and structure of the electron beam emitted from a point cathode operated in the mode of explosive electron emission are investigated. It is found that the rate of emission rise increases with the increasing voltage pulse amplitude. S P Bugaev et al, Power Nanosec Pulse Sources of Accel Electrons, CON, Nauka Novosibirsk 1974, 52-59 (in Russian). 31 1087. On the influence of pre-pulse on the value of current drawn from a cathode of vacuum diode operated in the mode of explosive emission. (USSR) At application on the cathode of a vacuum diode, operated in the mode of explosive emission, of two successive voltage pulses with duration of S x 10d9 s and equal amplitude of 1 x lo4 to 3 x 10“ V, the current during the second pulse is higher than the current during the first pulse. The influence of generation of anode flare on the ratio of pulse currents during successive pulses is found. G P Bazhenov and V P Rotshteyn, Power Nanosec Pulse Sources of Accel Electrons, Coil, Nauka Novosibirsk 1914, 67-71 (in Russian). 31 1088. On volt-ampere characteristic of diodes operated in the mode of explosive electron emission. (USSR) Operation of multiploint cathodes in the mode of explosive electron emission is investigated. X-ray patterns showing the structure of electron beam have been obtained. The emission current is described by the Child-Langmuir law. Volt-ampere characteristic of a pulse diode is presented. S P Bugaev et al, Power Nanosec Pulse Sources of Accel Electrons, Coil, Nauka Novosibirsk 1974, 63-67 (in Russian). 31 1089. Pre-breakdown phenomena of a positive point to plane in air at low pressure. (Czechoslovakia) A model of a positive primary streamer in air at low pressure was proposed according to experimental results and pre-breakdown phenomena were discussed quantitatively by this model. The experiments were performed with a tungsten point in air at a pressure of 3 torr. (Japan) M Akazaki et al, Proc of 11th Internat Conf on Phenom in Zoniz Gases, Prague 1973, 97. 31 1090. Investigation of the pre-ignition characteristics of a Knudsen diode with hot cathode. (Czechoslovakia) Pre-ignition characteristics of planar diodes with hot cathode and filled with xenon, helium and-caesium to pressures ranging from 5 x 10m4 to 10 torr are investigated. It is found that the cathode emission current value strongly influences the form of characteristics. (USSR) E P Busygin et al, Proc of 11th Internat Conf on Phenom in Zoniz Gases, Prague 1973, 99. 31 1091. One-sided ultrahigh-frequency nonresonance multipactor discharge. (Czechoslovekia) One-sided ultrahigh-frequency nonresonance multipactor discharge was experimentally studied in a rectangular vacuum waveguide ata 10 cm wavelength, pulsed power of 1 MW and 10 psec pulse length. A metal plate with the surface perpendicular to the UHF electric field was placed into the waveguide. (USSR) I A Kossy, et al, Proc of 11th Internat Conf on Phenom in Ioniz Gases, Prague 1973,93.
31 1092. An experimental investigation of pulsed low-pressure secondary electron resonant discharge in hydrogen. (Czechoslovakia) The effect of hydrogen pressure in the range of 1 x lo-’ to 5 x IO-“ torr on the characteristics of secondary electron resonant discharge is investigated in a vacuum rectangular waveguide. (USSR) W I Aleksandrow et al, Proc of 11th Internat Conf on Phenom in Ioniz Gases, Prague 1973, 94. 31 1093. Anode spot temperatures in vacuum arcs. (Czechoslovakia) Two pyrometers, one with a photomultiplier and the second with a germanium detector, were used to measure the anode spot temperature in low current dc vacuum arcs at geometries in which the ratio of the copper anode diameter to the inter-electrode gap is less than unity. (England) D Klapas and R Holmes, Proc of 11th Znternat Conf on Phenom in Ioniz Gases, Prqque 1973, 82. 31 1094. Experimental investigation of ion bombardment of cathodes in crossed electric and magnetic fields. (Czechoslovakia) The ion current to the cathode in a pulse magnetron diode is investigated at an argon pressure of 10m4 torr. The experimental device is described. (USSR) V J Maljugin et al, Proc of 11th Internat Conf on Phenom in Ioniz Gases, Prague 1973, 86. 33. GENERAL
PHYSICS
AND ELECTRONICS
33 1095. The modification of the refractive index of fluorite by heavy ion bombardment. (France) This paper deals with the possible realization of optical waves guides by heavy ion bombardment. The modification of the refractive index by bombardment was shown the first time by Koch and used on quartz and fused silica substrates. The modification of the fluorite substrate with Ne and N ions at about 40 keV is described. The new index and the penetration depth are computed from the values of the optical reflexion and transmission coefficients. J P Capuron et al, Vide, 29 (171-172), 1974, 337-340 (in French). 33 10%. The theory of the production of intense ions beams in the relativistic diode. (GB) Ions are considered to be generated within the diode either by laser ablation of the anode surface or through electron-neutral collisions taking place in front of the anode. Calculations are carried out for anode potentials up to 10 MV, and it is shown that the allowed ion currents can be several multiples of the Child-Langmuir limit. For both techniques of ion generation the optimum electron current required for space-charge neutralization can be readily produced by field emission, since the cathode electric field can exceed the spacecharge-free value. C B Wheeler, JPhys D: Appl Phys, 8 (2), 1975, 117-126. 33 1097. A simple locator for high energy beams (GB) A simple quadrant device is described which locates particle beams of energy greater than about 100 keV in complex beam flight systems. The sensing elements are thermistors which respond to the copious energy of the beam rather than to the small beam current usually sensed in comparable locators. The time constant of the locators is about 1 s which is adequate for most installations. The locators detect a beam imbalance of 20 nA between opposite quadrants. This sensitivity has proved to be extremely useful for channelling and backscattering from alkali halides which damage easily and require very small irradiation currents. (Australia) R L Dalglish and J C Kelly, J Phys E: Znstrum, 8 (2), 1975, 107-108. 33 1098. Description and performance of a high resolution electron spectrometer. (GB) The description of a high resolution electron spectrometer comprising an electron gun, electrostatic lenses, a 127” cylindrical monochromator and analyser, and a collision chamber with rotatable exit slit, is presented.Its performance is illustrated by a neon energylossspectrum and transmission measurements of helium and neon resonances. An analysis of these resonances is also carried out, and values of their energy widths (I‘) and phase shifts (6,) are determined. (Canada) D Roy et al, J Phys E: Scient Instrum, 8 (2), 1975, 109-l 14. 343
abstracts
3 1. EVACUATION
1085-l
098
AND SEALING 31:33
1085. On removing graphite dust from (electrical) parts. (USSR) A method of removing graphite dust from electrical components (likely to prove of particular value in the electronics industry and other fields using electrical vacuum apparatus) is described. To this end the parts in question are briefly immersed in liquified gases (helium, neon, argon, etc.). If the parts are very large they may alternatively be sprayed with these liquids. The removal of graphite from deep pores is further eased by heating the parts to lOO-170°C before immersion in the cryogenic liquid, so increasing the sudden temperature drop. G M Bntyrin, Soviet Patent, class H 01 j, 9102, No 391638, claimed 18 August 1971, publd 3 December 1973 (in Russian). 31 1086. Perveance and structure of electron beam in a diode with point cathode operated in the mode of explosive electron emission. (USSR) Current and structure of the electron beam emitted from a point cathode operated in the mode of explosive electron emission are investigated. It is found that the rate of emission rise increases with the increasing voltage pulse amplitude. S P Bugaev et al, Power Nanosec Pulse Sources of Accel Electrons, CON, Nauka Novosibirsk 1974, 52-59 (in Russian). 31 1087. On the influence of pre-pulse on the value of current drawn from a cathode of vacuum diode operated in the mode of explosive emission. (USSR) At application on the cathode of a vacuum diode, operated in the mode of explosive emission, of two successive voltage pulses with duration of S x 10d9 s and equal amplitude of 1 x lo4 to 3 x 10“ V, the current during the second pulse is higher than the current during the first pulse. The influence of generation of anode flare on the ratio of pulse currents during successive pulses is found. G P Bazhenov and V P Rotshteyn, Power Nanosec Pulse Sources of Accel Electrons, Coil, Nauka Novosibirsk 1914, 67-71 (in Russian). 31 1088. On volt-ampere characteristic of diodes operated in the mode of explosive electron emission. (USSR) Operation of multiploint cathodes in the mode of explosive electron emission is investigated. X-ray patterns showing the structure of electron beam have been obtained. The emission current is described by the Child-Langmuir law. Volt-ampere characteristic of a pulse diode is presented. S P Bugaev et al, Power Nanosec Pulse Sources of Accel Electrons, Coil, Nauka Novosibirsk 1974, 63-67 (in Russian). 31 1089. Pre-breakdown phenomena of a positive point to plane in air at low pressure. (Czechoslovakia) A model of a positive primary streamer in air at low pressure was proposed according to experimental results and pre-breakdown phenomena were discussed quantitatively by this model. The experiments were performed with a tungsten point in air at a pressure of 3 torr. (Japan) M Akazaki et al, Proc of 11th Internat Conf on Phenom in Zoniz Gases, Prague 1973, 97. 31 1090. Investigation of the pre-ignition characteristics of a Knudsen diode with hot cathode. (Czechoslovakia) Pre-ignition characteristics of planar diodes with hot cathode and filled with xenon, helium and-caesium to pressures ranging from 5 x 10m4 to 10 torr are investigated. It is found that the cathode emission current value strongly influences the form of characteristics. (USSR) E P Busygin et al, Proc of 11th Internat Conf on Phenom in Zoniz Gases, Prague 1973, 99. 31 1091. One-sided ultrahigh-frequency nonresonance multipactor discharge. (Czechoslovekia) One-sided ultrahigh-frequency nonresonance multipactor discharge was experimentally studied in a rectangular vacuum waveguide ata 10 cm wavelength, pulsed power of 1 MW and 10 psec pulse length. A metal plate with the surface perpendicular to the UHF electric field was placed into the waveguide. (USSR) I A Kossy, et al, Proc of 11th Internat Conf on Phenom in Ioniz Gases, Prague 1973,93.
31 1092. An experimental investigation of pulsed low-pressure secondary electron resonant discharge in hydrogen. (Czechoslovakia) The effect of hydrogen pressure in the range of 1 x lo-’ to 5 x IO-“ torr on the characteristics of secondary electron resonant discharge is investigated in a vacuum rectangular waveguide. (USSR) W I Aleksandrow et al, Proc of 11th Internat Conf on Phenom in Ioniz Gases, Prague 1973, 94. 31 1093. Anode spot temperatures in vacuum arcs. (Czechoslovakia) Two pyrometers, one with a photomultiplier and the second with a germanium detector, were used to measure the anode spot temperature in low current dc vacuum arcs at geometries in which the ratio of the copper anode diameter to the inter-electrode gap is less than unity. (England) D Klapas and R Holmes, Proc of 11th Znternat Conf on Phenom in Ioniz Gases, Prqque 1973, 82. 31 1094. Experimental investigation of ion bombardment of cathodes in crossed electric and magnetic fields. (Czechoslovakia) The ion current to the cathode in a pulse magnetron diode is investigated at an argon pressure of 10m4 torr. The experimental device is described. (USSR) V J Maljugin et al, Proc of 11th Internat Conf on Phenom in Ioniz Gases, Prague 1973, 86. 33. GENERAL
PHYSICS
AND ELECTRONICS
33 1095. The modification of the refractive index of fluorite by heavy ion bombardment. (France) This paper deals with the possible realization of optical waves guides by heavy ion bombardment. The modification of the refractive index by bombardment was shown the first time by Koch and used on quartz and fused silica substrates. The modification of the fluorite substrate with Ne and N ions at about 40 keV is described. The new index and the penetration depth are computed from the values of the optical reflexion and transmission coefficients. J P Capuron et al, Vide, 29 (171-172), 1974, 337-340 (in French). 33 10%. The theory of the production of intense ions beams in the relativistic diode. (GB) Ions are considered to be generated within the diode either by laser ablation of the anode surface or through electron-neutral collisions taking place in front of the anode. Calculations are carried out for anode potentials up to 10 MV, and it is shown that the allowed ion currents can be several multiples of the Child-Langmuir limit. For both techniques of ion generation the optimum electron current required for space-charge neutralization can be readily produced by field emission, since the cathode electric field can exceed the spacecharge-free value. C B Wheeler, JPhys D: Appl Phys, 8 (2), 1975, 117-126. 33 1097. A simple locator for high energy beams (GB) A simple quadrant device is described which locates particle beams of energy greater than about 100 keV in complex beam flight systems. The sensing elements are thermistors which respond to the copious energy of the beam rather than to the small beam current usually sensed in comparable locators. The time constant of the locators is about 1 s which is adequate for most installations. The locators detect a beam imbalance of 20 nA between opposite quadrants. This sensitivity has proved to be extremely useful for channelling and backscattering from alkali halides which damage easily and require very small irradiation currents. (Australia) R L Dalglish and J C Kelly, J Phys E: Znstrum, 8 (2), 1975, 107-108. 33 1098. Description and performance of a high resolution electron spectrometer. (GB) The description of a high resolution electron spectrometer comprising an electron gun, electrostatic lenses, a 127” cylindrical monochromator and analyser, and a collision chamber with rotatable exit slit, is presented.Its performance is illustrated by a neon energylossspectrum and transmission measurements of helium and neon resonances. An analysis of these resonances is also carried out, and values of their energy widths (I‘) and phase shifts (6,) are determined. (Canada) D Roy et al, J Phys E: Scient Instrum, 8 (2), 1975, 109-l 14. 343