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210. Electron optical bench
Classified
abstracts
206-217
target thickness of 3 x 1Ol5mol/cm2. The leakage rate from the target to vacuum is 48 cm3/hour. L I Pivovar and Yu Z Levchenko, 1970, 28-29 (in Russian).
Prib Tekh Eksper,
Nr 4, July-Aug
32 206. Investigation of plasma in Tokamak TM 3 machine by the probe method of fast hydrogen atom beam. (USSR)
Plasma investigation in the Tokamak TM 3 machine by a fast hydrogen atom beam probe, with energy of 4 to 14 keV, is described. The average proton concentration in the plasma is determined from the attenuation of the hydrogen atom beam after passage through plasma. A I Kislyakov and M P Petrov, Zh Tekh Fir, 40 (S), Aug 1970, 16091614 (in Russian). 207. On some properties of high current vacuum discharge plasma accelerator. (USSR)
32 in pulsed
The influence of the pinch effect on the character of spectrum emitted by a plasma, and the vacuum discharge structure in a plasma accelerator, are investigated. V A Derevschikov, Zh Tekh Fiz, 40 (7), July 1970, 15461549 (in Russian).
33. GENERAL PHYSICS AND ELECTRONICS 33 208. Atomic vibrations on pure and gold-doped (111) face of silicon. (USSR) Atomic vibrations on pure and gold-doped (111) face of silicon is investigated using low energy electron diffraction. This technique enables one to obtain the mean square displacement of surface atoms from the dependence of the reflected beam intensity on temperature. Silicon samples were chemically and ion etched. Measurements were carried out in vacuum at pressure of 3 x 10e9 torr. Gold was evaporated on the silicon surface from a special source. It is found that the mean square displacement amplitudes on a pure silicon surface are greater by a factor of 1.4 than in the bulk of crystal. This effect is explained by asymmetry of surface atom surroundings. The characteristic Debye temperature is found to be 440°K for a clean surface and 540°K for bulk silicon. Deposition of lOI cm-e gold atoms on the pure silicon surface followed by heating of the sample to 500°C results in formation of a new structure. Mean square displacement amplitudes of surface atoms are considerably increased and anharmonicity begins to influence the temperature dependencies of slow electron reflected beams. It is found that the Debye temperature on the doped and heated surface has a value of 175°K agreeing with the value characteristic for the bulk gold single crystal. Effects are discussed, in which the special features of silicon surface lattice dynamics should be manifest. B A Nesterenko and A D Borodkin, Fir Tverd Tela, 12 (7), July 1970, 2042-2046 (in Russian). 33 209. Method for obtaining slow electron beams. (USSR)
Par some purposes, as for example for neutralization of accelerated ion beams, intense beams of electrons with low energy are necessary, which flow to a great distance from the emitter. In this case the electron current is limited by space charge which does not allow high current densities to be obtained from the emitter. A method based on space charge neutralization by positive ions is presented. Positive ions are formed on the thermionic emitter s>Jrface by surface ionization. A spiral or cylinder, made of tungsten and heated to 2500-28WK, is used as the thermionic emitter of electrons and positive ions, in a caesium vapour beam. The caesium vapour beam is obtained in a caesium source connected by a canal to the thermionic emitter. The electron and ion currents were measured at a distance of 6 cm from the emitter. A current of 20 A of electrons with average energy from 1 to 8 eV and current density of 100 A/cm2 were obtained in the electron source. Using the equipotential thermionic emitter, an electron energy of 0.2 eV and electron current of 1 A, with a current density of 8 A/cm*, were achieved. The energetic value of electrons was 20 eV/el for the electron source at an electron current of 20 A. The pressure of caesium vapour was 10msto IO-* torr and residual gas pressure of 3 x lo+’ torr was measured. N F Balaev and R N Kuzmin, Zh Tekh Fiz, 40 17), Ju!,~ 1970, 1537-l 539 (in Russian). 148
33 210. Electron optical bench. (USSR) A universal electron-optical bench for physical modelling of lowfrequency and especially photoelectron, electro-vacuum devices and electron-optical investigations, is described. The vacuum system maintains a pressure of 2 x lo-’ torr in the stainless steel bench. The bench contains a special arrangement for photocathode preparation. G E Levin and P A Terekhov, Prib Tekh Eksper, Nr 4, July-Aug 1970, 240-241
(in Russian). 33
: 18
211. Infhmnce of edge shape on the field ion image.
(USSR) The image formation in a field ion microscope depends upon geometrical features of the specimen surface. A method for edge shape analysis from the observed field ion image is presented. The image from an ellipsoidal shape of edge is deduced. It is shown that the ion field image obtained by the calculation method is in good agreement with the experimental one. L P Potapov, Prib Tekh Eksper, Nr 4, July-Aug 1970, 181-183 (in Russian). 212. Neutral (Hungary)
atoms
in the beam
of a radio frequency
33 ion source.
The flow of neutral atoms in the ion current of the beam from a radio frequency ion source has been investigated as dependent on conditions of beam formation. D Bodizs, Atomki Kozlemenyek, 10 (3), 1968, 29-36 (in Hungarian). 213. Equilibrhun heavy elements.
distribution
33 of charge in a beam of fast ions of the
(USSR) Experimental data on the average charge and the width of equilibrium distribution of charge in beams of fast ions of different elements after their passage through solid material, are analyzed. V S Nikolaev and I S Dmitriev, Zh Tekh Fiz, 40 (8), Aug 1970, 17731776 (in Russian). 33 214. Probing of axially
symmetrical
electric and magnetic
fields by
charged particle beams. (USSR) Using the method of the Abel transformation, formulae are obtained which enable determination of the electric and magnetic field distribution in axially symmetrical vacuum systems from the charged particle beam deflection. A I Morozov, Zh Tekh Fiz, 40 (8), Aug 1970, 17761779 (in Russian). 33 215. Plasma surface states in semiconductors.
(USSR) New surface states in semiconductors are considered. Since the work function of a semiconductor is considerably higher than the characteristic thermal energy of conductivity electrons, the wave function of conductivity electrons should have a node on the semiconductor surface. For this reason the surface layer is deprived of electrons. This positive surface quantum charge results in band bending on the semiconductor surface. At least one surface state exists in the surface well thus produced, which is called a plasma surface state, as the charge forming it is due to electron plasma. The density of quantum surface charge is found for the free electron model in a plate. The screening of surface quantum charges is analyzed. Examples of the bonding energy of surface plasma states and the depths of surface potential well are given for some semiconductors. 0 V Konstantfnov and A Ya Shik, Zh Eksper Teor Fiz, 58 (5), May 1970, 1662-1674 (in Russian). 33 216. Formation
of synthesized
caesium plasma beam. I.
(USSR) The capture of electrons, emitted by an external source, in a positive caesium ion beam accelerated to an energy of 60 eV, was experimentally investigated in a vacuum apparatus. It is shown that with a neutralizer positive potential, electrons are not carried away by the ion beam on the collector, and that they only neutralize space charge. K S Golovanivskiy and A I Luschik, Z/I Tekh Fiz, 40 (7), July 1970, 1490-1496 (in Russian). 33 217. Application of x-ray microanalysis for electronic material testing with electron probe. (Poland)
The possibilities of application of an x-ray microanalyzer and electron probe for vacuum technology are discussed. A general description of the experimental method is given and results obtained for vacuum tight seals of metals, ceramics, and glass are presented. T Zero, Elektronika,
11 (l), 1970, 3641
(in Polish).
abstracts
206-217
target thickness of 3 x 1Ol5mol/cm2. The leakage rate from the target to vacuum is 48 cm3/hour. L I Pivovar and Yu Z Levchenko, 1970, 28-29 (in Russian).
Prib Tekh Eksper,
Nr 4, July-Aug
32 206. Investigation of plasma in Tokamak TM 3 machine by the probe method of fast hydrogen atom beam. (USSR)
Plasma investigation in the Tokamak TM 3 machine by a fast hydrogen atom beam probe, with energy of 4 to 14 keV, is described. The average proton concentration in the plasma is determined from the attenuation of the hydrogen atom beam after passage through plasma. A I Kislyakov and M P Petrov, Zh Tekh Fir, 40 (S), Aug 1970, 16091614 (in Russian). 207. On some properties of high current vacuum discharge plasma accelerator. (USSR)
32 in pulsed
The influence of the pinch effect on the character of spectrum emitted by a plasma, and the vacuum discharge structure in a plasma accelerator, are investigated. V A Derevschikov, Zh Tekh Fiz, 40 (7), July 1970, 15461549 (in Russian).
33. GENERAL PHYSICS AND ELECTRONICS 33 208. Atomic vibrations on pure and gold-doped (111) face of silicon. (USSR) Atomic vibrations on pure and gold-doped (111) face of silicon is investigated using low energy electron diffraction. This technique enables one to obtain the mean square displacement of surface atoms from the dependence of the reflected beam intensity on temperature. Silicon samples were chemically and ion etched. Measurements were carried out in vacuum at pressure of 3 x 10e9 torr. Gold was evaporated on the silicon surface from a special source. It is found that the mean square displacement amplitudes on a pure silicon surface are greater by a factor of 1.4 than in the bulk of crystal. This effect is explained by asymmetry of surface atom surroundings. The characteristic Debye temperature is found to be 440°K for a clean surface and 540°K for bulk silicon. Deposition of lOI cm-e gold atoms on the pure silicon surface followed by heating of the sample to 500°C results in formation of a new structure. Mean square displacement amplitudes of surface atoms are considerably increased and anharmonicity begins to influence the temperature dependencies of slow electron reflected beams. It is found that the Debye temperature on the doped and heated surface has a value of 175°K agreeing with the value characteristic for the bulk gold single crystal. Effects are discussed, in which the special features of silicon surface lattice dynamics should be manifest. B A Nesterenko and A D Borodkin, Fir Tverd Tela, 12 (7), July 1970, 2042-2046 (in Russian). 33 209. Method for obtaining slow electron beams. (USSR)
Par some purposes, as for example for neutralization of accelerated ion beams, intense beams of electrons with low energy are necessary, which flow to a great distance from the emitter. In this case the electron current is limited by space charge which does not allow high current densities to be obtained from the emitter. A method based on space charge neutralization by positive ions is presented. Positive ions are formed on the thermionic emitter s>Jrface by surface ionization. A spiral or cylinder, made of tungsten and heated to 2500-28WK, is used as the thermionic emitter of electrons and positive ions, in a caesium vapour beam. The caesium vapour beam is obtained in a caesium source connected by a canal to the thermionic emitter. The electron and ion currents were measured at a distance of 6 cm from the emitter. A current of 20 A of electrons with average energy from 1 to 8 eV and current density of 100 A/cm2 were obtained in the electron source. Using the equipotential thermionic emitter, an electron energy of 0.2 eV and electron current of 1 A, with a current density of 8 A/cm*, were achieved. The energetic value of electrons was 20 eV/el for the electron source at an electron current of 20 A. The pressure of caesium vapour was 10msto IO-* torr and residual gas pressure of 3 x lo+’ torr was measured. N F Balaev and R N Kuzmin, Zh Tekh Fiz, 40 17), Ju!,~ 1970, 1537-l 539 (in Russian). 148
33 210. Electron optical bench. (USSR) A universal electron-optical bench for physical modelling of lowfrequency and especially photoelectron, electro-vacuum devices and electron-optical investigations, is described. The vacuum system maintains a pressure of 2 x lo-’ torr in the stainless steel bench. The bench contains a special arrangement for photocathode preparation. G E Levin and P A Terekhov, Prib Tekh Eksper, Nr 4, July-Aug 1970, 240-241
(in Russian). 33
: 18
211. Infhmnce of edge shape on the field ion image.
(USSR) The image formation in a field ion microscope depends upon geometrical features of the specimen surface. A method for edge shape analysis from the observed field ion image is presented. The image from an ellipsoidal shape of edge is deduced. It is shown that the ion field image obtained by the calculation method is in good agreement with the experimental one. L P Potapov, Prib Tekh Eksper, Nr 4, July-Aug 1970, 181-183 (in Russian). 212. Neutral (Hungary)
atoms
in the beam
of a radio frequency
33 ion source.
The flow of neutral atoms in the ion current of the beam from a radio frequency ion source has been investigated as dependent on conditions of beam formation. D Bodizs, Atomki Kozlemenyek, 10 (3), 1968, 29-36 (in Hungarian). 213. Equilibrhun heavy elements.
distribution
33 of charge in a beam of fast ions of the
(USSR) Experimental data on the average charge and the width of equilibrium distribution of charge in beams of fast ions of different elements after their passage through solid material, are analyzed. V S Nikolaev and I S Dmitriev, Zh Tekh Fiz, 40 (8), Aug 1970, 17731776 (in Russian). 33 214. Probing of axially
symmetrical
electric and magnetic
fields by
charged particle beams. (USSR) Using the method of the Abel transformation, formulae are obtained which enable determination of the electric and magnetic field distribution in axially symmetrical vacuum systems from the charged particle beam deflection. A I Morozov, Zh Tekh Fiz, 40 (8), Aug 1970, 17761779 (in Russian). 33 215. Plasma surface states in semiconductors.
(USSR) New surface states in semiconductors are considered. Since the work function of a semiconductor is considerably higher than the characteristic thermal energy of conductivity electrons, the wave function of conductivity electrons should have a node on the semiconductor surface. For this reason the surface layer is deprived of electrons. This positive surface quantum charge results in band bending on the semiconductor surface. At least one surface state exists in the surface well thus produced, which is called a plasma surface state, as the charge forming it is due to electron plasma. The density of quantum surface charge is found for the free electron model in a plate. The screening of surface quantum charges is analyzed. Examples of the bonding energy of surface plasma states and the depths of surface potential well are given for some semiconductors. 0 V Konstantfnov and A Ya Shik, Zh Eksper Teor Fiz, 58 (5), May 1970, 1662-1674 (in Russian). 33 216. Formation
of synthesized
caesium plasma beam. I.
(USSR) The capture of electrons, emitted by an external source, in a positive caesium ion beam accelerated to an energy of 60 eV, was experimentally investigated in a vacuum apparatus. It is shown that with a neutralizer positive potential, electrons are not carried away by the ion beam on the collector, and that they only neutralize space charge. K S Golovanivskiy and A I Luschik, Z/I Tekh Fiz, 40 (7), July 1970, 1490-1496 (in Russian). 33 217. Application of x-ray microanalysis for electronic material testing with electron probe. (Poland)
The possibilities of application of an x-ray microanalyzer and electron probe for vacuum technology are discussed. A general description of the experimental method is given and results obtained for vacuum tight seals of metals, ceramics, and glass are presented. T Zero, Elektronika,
11 (l), 1970, 3641
(in Polish).