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650. Thermionic cathode
Classified
abstracts
33. GENERAL
649-660
PHYSICS
AND ELECTRONICS 33
649. Cathode. (USSR) A new type of cathode based on one of the metals of the platinum group with a smaller proportion of a rare-earth metal is described. Thus, for example, cathodes principally made of platinum, osmium, ruthenium, etc. alloyed with a few atomic percent of yttrium or a lanthanide metal have work functions of -2.8 eV and working temperatures of 1300-1500°C; they require no special activation and remain stable under electron bombardment. For preparing the alloys in question the pure metals may be fused directly, or alternatively borides, carbides, nitrides, etc, may be used as sources of metal. A A Gugnin et al, USSR Patent No 252,484, appl 15 Dee 1964, publd 7 May
1970. 33
650. Thermionic cathode.
(USSR) An improved form of rhenium cathode containing a proportion of thorium sufficient to ensure the formation of the intermetallic compound Re,Th is described. This material has a work function of 3.3 eV, as determined from the standard Richardson-Dushman formula, and a maximum secondary electron emission coefficient of 1.6, these parameters remaining intact at temperatures up to 1850°C. The alloy also possesses a high electrical and thermal conductivity, as well as stability of its emission characteristics under electron bombardment. A A Gugnin et al, USSR Patent No 270,087, appl 18 June 1964, publd 13 Aug 1970. 33 651. Method of studying the structure of an electron beam. (USSR) An improved system for studying the structure of an electron beam without the complicated procedure demanded by its predecessors (the photographic recording of fluorescence from excited residual gases followed by the conversion of photometric density into electron intensities) is described. In the new system, an optical image of the beam is formed on the photo-cathode of a transmitting television tube and is converted into an electron-optical image, creating potential relief on the tube target; by scanning the relief the geometrical characteristics of the electron beam may be directly converted into a series of oscillograms, and these may readily be interpreted in terms of the radial intensity distribution of the beam. A A Murav’ev et al, USSR Patent No 265,176, appl I8 Sept 1967, publd I7 June 1970. 33 652. Apparatus
of glass with a high content of lead and bismuth oxides and reduced in heated hydrogen, is investigated. Its length is 75 mm, inner diameter 0.7 mm and curvature radius 15 mm. It is shown that amplification of this curved channel amplifier is independent of pressure up to 2 x 1O-4 torr. In the straight multiplier of this type, the ion feedback effect occurs at 2x 10m5torr. The dependence of the amplification of the curved channel multiplier on channel voltage is determined. At 4 kV an amplification above lOa is reached. The output current is limited to a value of about 2x IO-@A due to a layer resistance of 8 x lo* ohm. The output pulse height distribution is also determined as a function of channel voltage. The investigated channel multipliers do not change their properties after prolonged exposure to air. During operation, property variations occur which are due to load changes. At an input current of IO-‘j A and channel voltage of 3400 V the amplification is reduced by about 20 per cent during the first 6 hours of operation. These measurements were performed in a vacuum system with an untrapped oil diffusion pump. The background counting rate is I2 pulses/min which corresponds to 3 x lO-2u A of the input current. F Muller and W Rickes. Exper Tech Phys, 18 (l-2), 1970, 17-19 (in German).
33 655. Vacuum monochromator MV-4 with differential pumping. (USSR) A vacuum monochromator type MV-4, with a concave diffraction grating, is described which is intended for investigation of the spectral and photoelectron characteristics of gaseous and solid materials. The vacuum system of the monochromator maintains the pressure difference from 2 torr in the radiation source to 2 x IO-’ torr in the measuring chamber. The spectral measuring range of the apparatus is from 500 to 3000 A. A hydrogen lamp working in the hydrogen flow produced by KOH electrolysis is used as a radiation source. Radiation is detected with the aid of a photoelectron multiplier. Construction of the vacuum monochromator and the electrical circuit diagram are presented. F I ViIesov and S N Lopatin, Vestn Leningrad Institut, No IO, 1970, 3842 (in Russian). 656. Increased life of heaters for high-temperature
cathodes.
The application of berrillium oxide as an electrical insulating material for heaters of L-cathodes is examined. It is found that heaters with a berillium oxide insulating coating exhibit 2 to 3 times longer life than alumina coated heaters, at high temperatures of 2000°C. AM Levin et al, Elektron Tekh Material, 2, 1970, 104-107 (in Russian).
for studying electron flows.
(USSR) A vacuum apparatus for studying the behaviour of electron beams in electric and magnetic fields is proposed. A special feature of the apparatus is the fact that it possesses auxiliary vacuum chambers and mechanisms for moving the electron gun and its associated equipment along the axes of these chambers in such a way as to facilitate beam analysis under a variety of geometrical and electromagnetic conditions, always maintaining exactly the same degree of vacuum in the working space. No breaking of the vacuum is required between measurements, nor is any supplementary evacuation or conditioning of the system needed. In this way the effect of the absolute degree of vacuum on the electron-beam measurements may be eliminated and the intrinsic gun characteristics analyzed in pure form. G P Egorov et al, USSR Patent No 263,753, appl 22 April 1966,
33 657. Analyzer of electron beam structure.
(USSR) An analyzer allowing investigation of the structure of an electron beam is described. The current density distribution and transversal velocities of electrons may also be determined. 0 A Koltsov and S F Gubin, Progres Tekhnol Novoe Oborud Proizv Elektron
Prib, Saratov
1970, 59-62 (in Russian).
658. Approximative calculation of magnetron. (USSR)
33 of electron impact energy on the anode
A method for calculation of the electron impact energy on the anode of a magnetron with secondary emission cathode is presented. V V Panshin, (in Russian).
Elektron
Tekh
Elektron
SVCh,
9,
1970,
233-235 33
publd 24 June 1970. 653. Continuous secondary electron multiplier for measurement (Germany) small electron currents of low energy.
33 (USSR)
33 of
A continuous secondary electron multiplier of the Ham&h type was placed inside a cylindrical electrode with the applied voltage between zero and full amplifier voltage. The amplification of the copper oxide or zinc oxide multiplier was measured as a function of the angle between the multiplier and the cylindrical electrode, the extraction voltage, and the voltage of the envelope electrode. Optimum conditions, with a plateau in the curve of output current versus applied voltage, were determined for residual gas pressures below 5 x 1Om8torr. G Blasek, Exper Tech Phusik, 18 (l-2), 1970, 13-16 (in German). 33 654. Investigation of channel electron multipliers of reduced lead glass. (Germany) Open electron multipliers are used for the detection of small electron and ion currents in high vacuum. A channel electron multiplier made
659. Switching properties and photoconduction
in GaSe.
(Germany) Switching properties have been observed on single crystals of GaSe. Gold electrodes were evaporated onto two cleaved c-faces of the crystals in a vacuum of 10-j torr. A study of the decay of the photocurrent in GaSe gives evidence for the existence of a continuum of localized energy levels in the forbidden gap, analogous to those found in amorphous semiconductors. (England) R H T&gold et al, Phys Stat Sol (a), 3 (2), Ott 1970, 407410. 660. Fatigue
of oxygen-caesium
photocathodes
33 in pulsed operation.
(USSR) Stability of the sensitivity of coaxial phototubes with oxygencaesium photocathodes is investigated in pulsed operation. It is found that a displacement of the spectra1 characteristic towards the short wave occurs during the initial period of pulse operation. A subsequent decrease in sensitivity over the whole spectra1 range is observed. L I Andreeva et al, Izmerit Tekh, No 9, Sept 1970, 45-46 (in Russian), 297
abstracts
33. GENERAL
649-660
PHYSICS
AND ELECTRONICS 33
649. Cathode. (USSR) A new type of cathode based on one of the metals of the platinum group with a smaller proportion of a rare-earth metal is described. Thus, for example, cathodes principally made of platinum, osmium, ruthenium, etc. alloyed with a few atomic percent of yttrium or a lanthanide metal have work functions of -2.8 eV and working temperatures of 1300-1500°C; they require no special activation and remain stable under electron bombardment. For preparing the alloys in question the pure metals may be fused directly, or alternatively borides, carbides, nitrides, etc, may be used as sources of metal. A A Gugnin et al, USSR Patent No 252,484, appl 15 Dee 1964, publd 7 May
1970. 33
650. Thermionic cathode.
(USSR) An improved form of rhenium cathode containing a proportion of thorium sufficient to ensure the formation of the intermetallic compound Re,Th is described. This material has a work function of 3.3 eV, as determined from the standard Richardson-Dushman formula, and a maximum secondary electron emission coefficient of 1.6, these parameters remaining intact at temperatures up to 1850°C. The alloy also possesses a high electrical and thermal conductivity, as well as stability of its emission characteristics under electron bombardment. A A Gugnin et al, USSR Patent No 270,087, appl 18 June 1964, publd 13 Aug 1970. 33 651. Method of studying the structure of an electron beam. (USSR) An improved system for studying the structure of an electron beam without the complicated procedure demanded by its predecessors (the photographic recording of fluorescence from excited residual gases followed by the conversion of photometric density into electron intensities) is described. In the new system, an optical image of the beam is formed on the photo-cathode of a transmitting television tube and is converted into an electron-optical image, creating potential relief on the tube target; by scanning the relief the geometrical characteristics of the electron beam may be directly converted into a series of oscillograms, and these may readily be interpreted in terms of the radial intensity distribution of the beam. A A Murav’ev et al, USSR Patent No 265,176, appl I8 Sept 1967, publd I7 June 1970. 33 652. Apparatus
of glass with a high content of lead and bismuth oxides and reduced in heated hydrogen, is investigated. Its length is 75 mm, inner diameter 0.7 mm and curvature radius 15 mm. It is shown that amplification of this curved channel amplifier is independent of pressure up to 2 x 1O-4 torr. In the straight multiplier of this type, the ion feedback effect occurs at 2x 10m5torr. The dependence of the amplification of the curved channel multiplier on channel voltage is determined. At 4 kV an amplification above lOa is reached. The output current is limited to a value of about 2x IO-@A due to a layer resistance of 8 x lo* ohm. The output pulse height distribution is also determined as a function of channel voltage. The investigated channel multipliers do not change their properties after prolonged exposure to air. During operation, property variations occur which are due to load changes. At an input current of IO-‘j A and channel voltage of 3400 V the amplification is reduced by about 20 per cent during the first 6 hours of operation. These measurements were performed in a vacuum system with an untrapped oil diffusion pump. The background counting rate is I2 pulses/min which corresponds to 3 x lO-2u A of the input current. F Muller and W Rickes. Exper Tech Phys, 18 (l-2), 1970, 17-19 (in German).
33 655. Vacuum monochromator MV-4 with differential pumping. (USSR) A vacuum monochromator type MV-4, with a concave diffraction grating, is described which is intended for investigation of the spectral and photoelectron characteristics of gaseous and solid materials. The vacuum system of the monochromator maintains the pressure difference from 2 torr in the radiation source to 2 x IO-’ torr in the measuring chamber. The spectral measuring range of the apparatus is from 500 to 3000 A. A hydrogen lamp working in the hydrogen flow produced by KOH electrolysis is used as a radiation source. Radiation is detected with the aid of a photoelectron multiplier. Construction of the vacuum monochromator and the electrical circuit diagram are presented. F I ViIesov and S N Lopatin, Vestn Leningrad Institut, No IO, 1970, 3842 (in Russian). 656. Increased life of heaters for high-temperature
cathodes.
The application of berrillium oxide as an electrical insulating material for heaters of L-cathodes is examined. It is found that heaters with a berillium oxide insulating coating exhibit 2 to 3 times longer life than alumina coated heaters, at high temperatures of 2000°C. AM Levin et al, Elektron Tekh Material, 2, 1970, 104-107 (in Russian).
for studying electron flows.
(USSR) A vacuum apparatus for studying the behaviour of electron beams in electric and magnetic fields is proposed. A special feature of the apparatus is the fact that it possesses auxiliary vacuum chambers and mechanisms for moving the electron gun and its associated equipment along the axes of these chambers in such a way as to facilitate beam analysis under a variety of geometrical and electromagnetic conditions, always maintaining exactly the same degree of vacuum in the working space. No breaking of the vacuum is required between measurements, nor is any supplementary evacuation or conditioning of the system needed. In this way the effect of the absolute degree of vacuum on the electron-beam measurements may be eliminated and the intrinsic gun characteristics analyzed in pure form. G P Egorov et al, USSR Patent No 263,753, appl 22 April 1966,
33 657. Analyzer of electron beam structure.
(USSR) An analyzer allowing investigation of the structure of an electron beam is described. The current density distribution and transversal velocities of electrons may also be determined. 0 A Koltsov and S F Gubin, Progres Tekhnol Novoe Oborud Proizv Elektron
Prib, Saratov
1970, 59-62 (in Russian).
658. Approximative calculation of magnetron. (USSR)
33 of electron impact energy on the anode
A method for calculation of the electron impact energy on the anode of a magnetron with secondary emission cathode is presented. V V Panshin, (in Russian).
Elektron
Tekh
Elektron
SVCh,
9,
1970,
233-235 33
publd 24 June 1970. 653. Continuous secondary electron multiplier for measurement (Germany) small electron currents of low energy.
33 (USSR)
33 of
A continuous secondary electron multiplier of the Ham&h type was placed inside a cylindrical electrode with the applied voltage between zero and full amplifier voltage. The amplification of the copper oxide or zinc oxide multiplier was measured as a function of the angle between the multiplier and the cylindrical electrode, the extraction voltage, and the voltage of the envelope electrode. Optimum conditions, with a plateau in the curve of output current versus applied voltage, were determined for residual gas pressures below 5 x 1Om8torr. G Blasek, Exper Tech Phusik, 18 (l-2), 1970, 13-16 (in German). 33 654. Investigation of channel electron multipliers of reduced lead glass. (Germany) Open electron multipliers are used for the detection of small electron and ion currents in high vacuum. A channel electron multiplier made
659. Switching properties and photoconduction
in GaSe.
(Germany) Switching properties have been observed on single crystals of GaSe. Gold electrodes were evaporated onto two cleaved c-faces of the crystals in a vacuum of 10-j torr. A study of the decay of the photocurrent in GaSe gives evidence for the existence of a continuum of localized energy levels in the forbidden gap, analogous to those found in amorphous semiconductors. (England) R H T&gold et al, Phys Stat Sol (a), 3 (2), Ott 1970, 407410. 660. Fatigue
of oxygen-caesium
photocathodes
33 in pulsed operation.
(USSR) Stability of the sensitivity of coaxial phototubes with oxygencaesium photocathodes is investigated in pulsed operation. It is found that a displacement of the spectra1 characteristic towards the short wave occurs during the initial period of pulse operation. A subsequent decrease in sensitivity over the whole spectra1 range is observed. L I Andreeva et al, Izmerit Tekh, No 9, Sept 1970, 45-46 (in Russian), 297