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578. Acceleration of ions of cathode material at vacuum breakdown
Classified abstracts 570--579 31 570. Volt-ampere characteristics of caesium diodes at high current densities. (USSR) Volt-ampere characteristics of directly heated caesium diodes with ZrC cathodes are measured in the range of cathode temperature of 2000 to 3000°K, caesium vapour pressure of 10-2 to 5 torr and interelectrode distance of 0.3 to 0.5 ram. It is found that the shape of the volt-ampere characteristic at high current densities depends on conditions of measurement, whether it is measured at constant cathode temperature or constant cathode power. A small change in the emission current at low caesium vapour pressure can cause a stepwise change in the anode current. T L Matskevieh and T V Krachino, Zh Tekh Fiz, 41 (6), 1971, 11821187 (in Russian). 31 571. To the problem of evacuation of electro-vacuum devices with separated parts. (USSR) The possibility of simulating the evacuation process of electrovacuum devices with separated parts, is demonstrated. The experimentally obtained optimum separation of the body and the disc of an electro-vacuum device is 22 per cent of the body diameter. The discrepancy between the experimental and calculated data is explained by background of the vacuum equipment. C F Budnikov et ai, Electronic Technology, Scient-Techn Collect, Technology and Organization of Production, No 3, 1971, 25-29 (in
Russian). 31 572. Evacuation of electron tubes by means of oil-free vacuum systems. (Poland) An oil-free vacuum system for evacuation of electron tubes is described. The vacuum system consists of two sputter-ion pumps with highvacuum metallic valves and two cryosorption pumps containing molecular sieves. The high-vacuum part of the vacuum system is bakeable to 400°C. Evacuation to pressure of 6 to 9 x 10-3 tort is performed with the aid of the cryosorption pumps. Hydrogen and inert gases form the main constituents of residual gas. Then the glass parts are degassed at 300°C. Further degassing and operations are performed during evacuation by the sputter ion pumps. Gases desorbed from glass surfaces are thus pumped away by the cryosorption pump. Residual gas analysis performed with the aid of an omegatron showed that heavy hydrocarbons are absent in the vacuum system and that relatively high pressures of helium and neon are present. J Sobanski and E Szymala, Prace PIE, 11 (3), 1970, 173-176 (in
Polish). 31 573. Variations in contact potential difference of surface of components of electro-vacuum and semiconductor devices during technological operations. (USSR) An instrument for rapid determination of contact potential difference of metal and semiconductor surfaces is described. Sensitivity of the instrument with vibrating capacitor is 1 inV. Conditions of stabilization of the surface state of the gold reference electrode are given. Variations in contact potential difference of surfaces of copper, nickel, germanium and silicon in various technical and chemical treatments are investigated. The experimental results show that measurement of contact potential difference can be used for inspection of state of surfaces of electro-vacuum and semiconductor device components. A T Lebodev and Yu A Ryabikov, Electronic Technology, Scient-Techn Collect, UHF Electronics, No 8, 1971, 64-74 (in Russian). 31 574. Influence of sealing temperature on vacuum in devices. (USSR) Low pressure in the working volume is one of the basic factors determining correct functioning and long life of electro-vacuum devices. Recent investigations show that reliability of ultrahigh frequency electro-vacuum devices is improved if they are evacuated to pressures of the order of 10-9 torr. The residual pressure attained in the device during evacuation and degassing considerably depends on the method of sealing. Investigations of the degassing stages show that the highest temperature of the device during degassing and hermetization is preferable for the attainment of ultrahigh vacuum. The experiments to determine the influence of the sealing temperature on the residual pressure in the device are carried out. The results confirm the advantages of hot hermetization and indicate the necessity of further theoretical and experimental studies to determine the
172
optimum hermetization temperatures for different types of electrovacuum devices. G V Konyushkov et al, Electronic Technology, Scient-Techn Collect, Technology and Organization of Production, No 3, 1971, 30-32 (in
Russian). 32. NUCLEONICS 32 575. Investigation of the parameters of an impulse erosion plasma accelerator. (USSR) An impulse rail plasma accelerator is investigated, in which a fluorine plastic is employed as insulator and working substance. Discharge is initiated along the insulator surface by a low-power coaxial gun. The accelerator is placed in a chamber, in which vacuum of 2 to 3 x 10-6 torr is maintained. A battery of capacitors with capacity of 824/~F and working voltage of 15 to 30 kV is used in the accelerator supply. Distributors of electron concentration, and electric and magnetic fields inside the accelerator are investigated with the aid of electric and magnetic probes. A G Kalygin et al, Zh Tekh Fiz, 41 (10), Oct 1971,2084--2087 (in Russian). 32 576. Investigation of stability of a closed proton beam in ionized residual gas. (USSR) Experimental data on influence of secondary charged particles on the stability of a closed proton beam in a storage ring, and a qualitative explanation of the observed effects is presented. The experiments were performed in a storage ring with average orbit radius of 100 cm and residual pressure of 4.6 × 10-5 torr. Conditions are found, under which the proton beam fully compensated by secondary electrons is stable with the number of particles in the path near to the limiting number given by space charge. G I Dimov et al, Zh Tekh Fiz, 41 (10), Oct 1971,2098-2102 (in Russian). 32 577. Injector of fast hydrogen atoms. If. Production of proton and neutral beams. (USSR) An injector producing a beam of hydrogen atoms with energy of 15 to 30 keV and intensity above 0.5 equivalent amperes, is described. The proton beam is produced in a gas-discharge source operating in a magnetic field. The atomic beam is produced from the protons by charge transfer on a gaseous target of magnesium vapour. The preworking pressure in the injector is 1 x 10-6 torr. When hydrogen is admitted into the source, the pressure in the injector increases to 2 to 3 x 10-6 tort. A A Panasenkov and N N Semashko, Zh Tekh Fiz, 40 (12), 1970, 25252533 (in Russian). 32 578. Acceleration of ions of cathode material at vacuum breakdown. (USSR) Results of investigations of the process of acceleration of ions of cathode materials during impulse breakdown of a 1 to 2 cm vacuum gap are presented. The experimental setup was pumped by an oil diffusion pump to pressure of 1 x 10-5 torr. Edges of different metals (AI, Mg, Cu, Fe and W) were examined, Mass composition and energies of ions accelerated to the anode were analyzed with the aid of Thomson parabolic mass spectrograph. It is shown that at the high-voltage stage of the breakdown, the ions are accelerated to the anode during the moments of electron current bursts from the cathode. Axial contraction of the electron current up to a density of 10 kA/cm 2 is observed in the vacuum gap. Maximum ion energies reach 10 to 15 MeV at a breakdown voltage of 300 kV. The processes taking place at current flow, ion acceleration at vacuum breakdown, and in the formation of electron beams from plasma emitters in unstable stages, are considered. E D Korop and A A Plyutto, Zh Tekh Fiz, 40 (12), 1970, 2534-2537
(in Russian). 32 579. The Leningrad 1 GeV proton synchrocyciotron. (USSR) The 1 GeV proton synchrocyclotron built in Leningrad is described. Parameters of the proton beam and characteristics of the basic systems are presented. The vacuum chamber has a volume of 35 m z. A pressure of 3 to 5 x 10-6 torr in the chamber during the acceleration stage is maintained by oil diffusion pump aggregates with a total effective pumping speed of 36000 litres/sec. The traps are cooled by liquid nitrogen. N K Abrasimov et al, Zh Tekh Fiz, 41 (9), Sept 1971, 1769-1775 (in
Russian).
Russian). 31 572. Evacuation of electron tubes by means of oil-free vacuum systems. (Poland) An oil-free vacuum system for evacuation of electron tubes is described. The vacuum system consists of two sputter-ion pumps with highvacuum metallic valves and two cryosorption pumps containing molecular sieves. The high-vacuum part of the vacuum system is bakeable to 400°C. Evacuation to pressure of 6 to 9 x 10-3 tort is performed with the aid of the cryosorption pumps. Hydrogen and inert gases form the main constituents of residual gas. Then the glass parts are degassed at 300°C. Further degassing and operations are performed during evacuation by the sputter ion pumps. Gases desorbed from glass surfaces are thus pumped away by the cryosorption pump. Residual gas analysis performed with the aid of an omegatron showed that heavy hydrocarbons are absent in the vacuum system and that relatively high pressures of helium and neon are present. J Sobanski and E Szymala, Prace PIE, 11 (3), 1970, 173-176 (in
Polish). 31 573. Variations in contact potential difference of surface of components of electro-vacuum and semiconductor devices during technological operations. (USSR) An instrument for rapid determination of contact potential difference of metal and semiconductor surfaces is described. Sensitivity of the instrument with vibrating capacitor is 1 inV. Conditions of stabilization of the surface state of the gold reference electrode are given. Variations in contact potential difference of surfaces of copper, nickel, germanium and silicon in various technical and chemical treatments are investigated. The experimental results show that measurement of contact potential difference can be used for inspection of state of surfaces of electro-vacuum and semiconductor device components. A T Lebodev and Yu A Ryabikov, Electronic Technology, Scient-Techn Collect, UHF Electronics, No 8, 1971, 64-74 (in Russian). 31 574. Influence of sealing temperature on vacuum in devices. (USSR) Low pressure in the working volume is one of the basic factors determining correct functioning and long life of electro-vacuum devices. Recent investigations show that reliability of ultrahigh frequency electro-vacuum devices is improved if they are evacuated to pressures of the order of 10-9 torr. The residual pressure attained in the device during evacuation and degassing considerably depends on the method of sealing. Investigations of the degassing stages show that the highest temperature of the device during degassing and hermetization is preferable for the attainment of ultrahigh vacuum. The experiments to determine the influence of the sealing temperature on the residual pressure in the device are carried out. The results confirm the advantages of hot hermetization and indicate the necessity of further theoretical and experimental studies to determine the
172
optimum hermetization temperatures for different types of electrovacuum devices. G V Konyushkov et al, Electronic Technology, Scient-Techn Collect, Technology and Organization of Production, No 3, 1971, 30-32 (in
Russian). 32. NUCLEONICS 32 575. Investigation of the parameters of an impulse erosion plasma accelerator. (USSR) An impulse rail plasma accelerator is investigated, in which a fluorine plastic is employed as insulator and working substance. Discharge is initiated along the insulator surface by a low-power coaxial gun. The accelerator is placed in a chamber, in which vacuum of 2 to 3 x 10-6 torr is maintained. A battery of capacitors with capacity of 824/~F and working voltage of 15 to 30 kV is used in the accelerator supply. Distributors of electron concentration, and electric and magnetic fields inside the accelerator are investigated with the aid of electric and magnetic probes. A G Kalygin et al, Zh Tekh Fiz, 41 (10), Oct 1971,2084--2087 (in Russian). 32 576. Investigation of stability of a closed proton beam in ionized residual gas. (USSR) Experimental data on influence of secondary charged particles on the stability of a closed proton beam in a storage ring, and a qualitative explanation of the observed effects is presented. The experiments were performed in a storage ring with average orbit radius of 100 cm and residual pressure of 4.6 × 10-5 torr. Conditions are found, under which the proton beam fully compensated by secondary electrons is stable with the number of particles in the path near to the limiting number given by space charge. G I Dimov et al, Zh Tekh Fiz, 41 (10), Oct 1971,2098-2102 (in Russian). 32 577. Injector of fast hydrogen atoms. If. Production of proton and neutral beams. (USSR) An injector producing a beam of hydrogen atoms with energy of 15 to 30 keV and intensity above 0.5 equivalent amperes, is described. The proton beam is produced in a gas-discharge source operating in a magnetic field. The atomic beam is produced from the protons by charge transfer on a gaseous target of magnesium vapour. The preworking pressure in the injector is 1 x 10-6 torr. When hydrogen is admitted into the source, the pressure in the injector increases to 2 to 3 x 10-6 tort. A A Panasenkov and N N Semashko, Zh Tekh Fiz, 40 (12), 1970, 25252533 (in Russian). 32 578. Acceleration of ions of cathode material at vacuum breakdown. (USSR) Results of investigations of the process of acceleration of ions of cathode materials during impulse breakdown of a 1 to 2 cm vacuum gap are presented. The experimental setup was pumped by an oil diffusion pump to pressure of 1 x 10-5 torr. Edges of different metals (AI, Mg, Cu, Fe and W) were examined, Mass composition and energies of ions accelerated to the anode were analyzed with the aid of Thomson parabolic mass spectrograph. It is shown that at the high-voltage stage of the breakdown, the ions are accelerated to the anode during the moments of electron current bursts from the cathode. Axial contraction of the electron current up to a density of 10 kA/cm 2 is observed in the vacuum gap. Maximum ion energies reach 10 to 15 MeV at a breakdown voltage of 300 kV. The processes taking place at current flow, ion acceleration at vacuum breakdown, and in the formation of electron beams from plasma emitters in unstable stages, are considered. E D Korop and A A Plyutto, Zh Tekh Fiz, 40 (12), 1970, 2534-2537
(in Russian). 32 579. The Leningrad 1 GeV proton synchrocyciotron. (USSR) The 1 GeV proton synchrocyclotron built in Leningrad is described. Parameters of the proton beam and characteristics of the basic systems are presented. The vacuum chamber has a volume of 35 m z. A pressure of 3 to 5 x 10-6 torr in the chamber during the acceleration stage is maintained by oil diffusion pump aggregates with a total effective pumping speed of 36000 litres/sec. The traps are cooled by liquid nitrogen. N K Abrasimov et al, Zh Tekh Fiz, 41 (9), Sept 1971, 1769-1775 (in
Russian).