- Email: [email protected]
Electron microscope EM-150
Classified
abstracts
913-925
described. The system is placed in a glass vacuum chamber evacuated to a pressure lower than 1 x 1O-8 torr. V B Braginskiy et al, Prib Tekh Eksper, No 6, 1971, 177-179 (in Russian). 33 913. Ion mass-spectrometric
microscope. (USSR) Ion mass-spectrometric microscope enables investigation of the concentration of light elements in solids (metals, semi-conductors and dielectrics) both in the surface layer and in the volume using both ion microscope and mass spectrometric techniques. Optical resolution is 1 to 2 pm at magnification of 150 x . The mass range is 1 to 120 amu, mass-spectrometric resolution is 60 at sensitivity of 2 x 10-a per cent. The resolution in depth for layer analysis is 150 to 200 A. The residual gas pressure in the chamber of the instrument is 1 x 1O-Btorr. Yu P Mayfet and V T Cherepin, Prib Tekh Eksper, No 5, 1971,267 (in Russian).
33 914. Electron microscope EM-150. (USSR) The electron transmission microscope EM-150, with resolution of 5 A and accelerating voltage up to 150 kV, is described. The electrodes and high-voltage insulator in the electron gun can be heated and pressures of 1 to 5 x lo-’ torr are rapidly attained in the gun chamber by means of a 100 litre/sec oil diffusion pump. The working pressure of 1 to 5 x 1O-Btorr in the column is maintained by a 500 litre/sec oil diffusion pump. P A Stoyanov et al, Prib Tekh Eksper, No 5, 1971,268 (in Russian). 33 915. Application of vacuum spark relays in pulse generators for laser
starting. (USSR) A circuit using vacuum spark relays for generating pulses to supply power for solid state lasers, is described. I M Divilkovskiy et al, Prib Tekh Eksper, No 2, 1971,202 (in Russian). 33 916. Optimum geometry of discharge chamber of ion source. (USSR)
Optimum geometry for the arc-discharge chamber of a plasma ion source is determined. Yu P Grigorev and P M Morozov, Zh Tekh Fiz, 41 (ll), Nov 1971, 2428-2430 (in Russian). 33 917. Preparation of thin metallic foils for electron microscopy by ion
bombardment in vacuum. (Czechoslovakia) Cathodic sputtering in vacuum is employed to prepare thin metallic foils of samples for transmission electron microscopy investigations. The experimental diode system filled with argon to pressure of low2 to 1O-3 torr is described. Accelerating voltage was 2 to 5 kV and the current density 0.7 mA/cm2. It is found that thinning by ion bombardment in vacuum does not affect the dislocation configuration of the sample. Advantages of this method are the elimination of surface layers obtained by polishing or oxidation, and the avoidance of planar weakening and instantaneous interruption of the process. Cathodic sputtering can be applied to various materials including ceramics and paper. The main operations (choice of accelerating voltage, type of ions, their density and direction) can be easily controlled. The sputtering rate can be increased and perfect reproducibility is easily obtained. M Molcik, Jemna Mech Optika, 17 (l), Jan 1972, 10-15 (in Czech). 33 918. Studies of electron impact excitation, negative ion formation, and negative ion-molecule reactions in boron trifluoride and boron trichloride. (USA) Both electron swarm and electron beam techniques were used. Thermal electron attachment rates were determined by the drift-dwelldrift technique to be <5 x lo5 set-’ torr-’ for BF, and 9 x lo1 SW-’ torr-’ for Bkl,. Beam studies showed that F-, Fe and BF, were produced from BF, bv electrons of energY near 11.5 eV while Cl- and Cl; were produced-in BCl, near 1 eV.The SK threshold electron impact excitation spectrum of BF, exhibited no structure. However, a number of peaks were seen in BCl,, the chief one being near 7.6 eV. Thermal energy rates for the reactions studied are given. J A Stockdale et al, J Chem Phys, 56 (7), 1st April 1972, 3336-3341. 33 919. Angular dependence of electron impact excitation cross sections of
0,. (USA) These studies were made at 20 and 45 eV impact energies and at scattering angles ranging from 10” to 90”. The experimentally meas-
ured relative differential and integral cross sections were approximately normalized to the absolute scale. The interactions of the different transitions in optical and electron-impact spectra are compared and the importance of spin-orbit coupling and exchange processes are discussed. S Trajmar, J Chem Phys, 56 (8), 15th Aprif 1972,3759-3765. 33 920. Ion-molecule reactions of ethane at low electron energy. (USA) These reactions were examined by ICR spectroscopy at 13 eV and ~10-~ torr. The interpretation of single- and double-resonance peak heights under these conditions is discussed qualitatively, and the double resonance spectra are used to design relative rates to the observed reactions. The chemistry is strikingly different from that at higher electron energy. These results are discussed in some detail. R C Dunbar et al, J Chem Phys, 56 (8), 15th ApriI 1972,3794-3798. 33 921. Metallic hydride targets for the production of neutrons. Operation
and preparation. (France) Mechanisms affecting the performance of hydride targets for the production of neutrons are investigated. The principal cause of target deterioration with time, is the dilution of tritium in the target by deuterium from the ion beam. A simplified theoretical approach is described which allows calculation of the half-life of any target and which gives results in good agreement with experimental values. The design of an apparatus for the preparation of tritium targets is described. After volatilization of the metal, the target is held under a vacuum of lo--’ torr until the impregnation of the layer. J DCtaint et al, Le Vide, 26 (154), July-Aug-Sepf-Ott, 1971, 143-149 (in French). 33 922. Path separation type, non-magnetic mass spectrometer.
(Japan) A non-magnetic mass spectrometer of the path separation type, with parallel plane electrodes was studied. The sensor consisted of two side plates with a rectangular box inserted between them. A square wave negative rf voltage is applied to the box electrode which has two windows with grids on both sides. A collimated ion beam injected into the space between the first side plate and the box, along the tube axis, is accelerated to the box and after passing through the box is then decelerated between the box and the other side plate. Composite ions in the beam disperse in directions corresponding to mass number and only ions directed along the tube axis can reach the collector through the exit collimator. To obtain mass spectra, the frequency of the rf voltage was swept. Resolving power was 27 and current efficiency was about 4 per cent which was in good agreement with expected values. The resolving power is independent of the velocity distribution of the ions and the theoretically possible efficiency would be 50 per cent. Methods of improving the performance are discussed. F Kanematsu and H Mhna, J Vat Sot Japan, 14 (12), 1971,431-435 (in Japanese). 33 923. Transistorized
high-frequency generator for monopole mass spectrometer. (USSR) Circuit diagram of a high-frequency transistorized generator for a monopole mass spectrometer is described. The generator employs a feedback circuit for stabilization of output voltage; crystal stabilization of oscillator frequency; and it provides manual and automatic scanning of the output voltage from 5 to 1500 V on frequencies of l-3 MHz. L F Berzin, Prib Tekh Eksper, No 5,1971, 120-122 (in Russian). 33 924. Ion source of mass spectrometer MI-1305 for investigations at
high temperatures. (USSR) An ion source with a heater for investigation of composition of a gas phase in equilibrium with a condensed phase heated to 2000°K is described. A movable diaphragm is placed between the Knudsen cell and the cooling system. K Skudlarskl, Prib Tekh Eksper, No 2, 1971,268-269 (in Russian). 33 925. Formation of H- ions by charge exchange of 1.540
keV protons
in thick streams of Li, Na, K and Mg vapours. (USSR) The formation of negative hydrogen ions by charge exchange of 1.5-10 keV protons in thick streams of Na, Li, K and Mg vapours is studied experimentally in a vacuum system. It is found that Na
abstracts
913-925
described. The system is placed in a glass vacuum chamber evacuated to a pressure lower than 1 x 1O-8 torr. V B Braginskiy et al, Prib Tekh Eksper, No 6, 1971, 177-179 (in Russian). 33 913. Ion mass-spectrometric
microscope. (USSR) Ion mass-spectrometric microscope enables investigation of the concentration of light elements in solids (metals, semi-conductors and dielectrics) both in the surface layer and in the volume using both ion microscope and mass spectrometric techniques. Optical resolution is 1 to 2 pm at magnification of 150 x . The mass range is 1 to 120 amu, mass-spectrometric resolution is 60 at sensitivity of 2 x 10-a per cent. The resolution in depth for layer analysis is 150 to 200 A. The residual gas pressure in the chamber of the instrument is 1 x 1O-Btorr. Yu P Mayfet and V T Cherepin, Prib Tekh Eksper, No 5, 1971,267 (in Russian).
33 914. Electron microscope EM-150. (USSR) The electron transmission microscope EM-150, with resolution of 5 A and accelerating voltage up to 150 kV, is described. The electrodes and high-voltage insulator in the electron gun can be heated and pressures of 1 to 5 x lo-’ torr are rapidly attained in the gun chamber by means of a 100 litre/sec oil diffusion pump. The working pressure of 1 to 5 x 1O-Btorr in the column is maintained by a 500 litre/sec oil diffusion pump. P A Stoyanov et al, Prib Tekh Eksper, No 5, 1971,268 (in Russian). 33 915. Application of vacuum spark relays in pulse generators for laser
starting. (USSR) A circuit using vacuum spark relays for generating pulses to supply power for solid state lasers, is described. I M Divilkovskiy et al, Prib Tekh Eksper, No 2, 1971,202 (in Russian). 33 916. Optimum geometry of discharge chamber of ion source. (USSR)
Optimum geometry for the arc-discharge chamber of a plasma ion source is determined. Yu P Grigorev and P M Morozov, Zh Tekh Fiz, 41 (ll), Nov 1971, 2428-2430 (in Russian). 33 917. Preparation of thin metallic foils for electron microscopy by ion
bombardment in vacuum. (Czechoslovakia) Cathodic sputtering in vacuum is employed to prepare thin metallic foils of samples for transmission electron microscopy investigations. The experimental diode system filled with argon to pressure of low2 to 1O-3 torr is described. Accelerating voltage was 2 to 5 kV and the current density 0.7 mA/cm2. It is found that thinning by ion bombardment in vacuum does not affect the dislocation configuration of the sample. Advantages of this method are the elimination of surface layers obtained by polishing or oxidation, and the avoidance of planar weakening and instantaneous interruption of the process. Cathodic sputtering can be applied to various materials including ceramics and paper. The main operations (choice of accelerating voltage, type of ions, their density and direction) can be easily controlled. The sputtering rate can be increased and perfect reproducibility is easily obtained. M Molcik, Jemna Mech Optika, 17 (l), Jan 1972, 10-15 (in Czech). 33 918. Studies of electron impact excitation, negative ion formation, and negative ion-molecule reactions in boron trifluoride and boron trichloride. (USA) Both electron swarm and electron beam techniques were used. Thermal electron attachment rates were determined by the drift-dwelldrift technique to be <5 x lo5 set-’ torr-’ for BF, and 9 x lo1 SW-’ torr-’ for Bkl,. Beam studies showed that F-, Fe and BF, were produced from BF, bv electrons of energY near 11.5 eV while Cl- and Cl; were produced-in BCl, near 1 eV.The SK threshold electron impact excitation spectrum of BF, exhibited no structure. However, a number of peaks were seen in BCl,, the chief one being near 7.6 eV. Thermal energy rates for the reactions studied are given. J A Stockdale et al, J Chem Phys, 56 (7), 1st April 1972, 3336-3341. 33 919. Angular dependence of electron impact excitation cross sections of
0,. (USA) These studies were made at 20 and 45 eV impact energies and at scattering angles ranging from 10” to 90”. The experimentally meas-
ured relative differential and integral cross sections were approximately normalized to the absolute scale. The interactions of the different transitions in optical and electron-impact spectra are compared and the importance of spin-orbit coupling and exchange processes are discussed. S Trajmar, J Chem Phys, 56 (8), 15th Aprif 1972,3759-3765. 33 920. Ion-molecule reactions of ethane at low electron energy. (USA) These reactions were examined by ICR spectroscopy at 13 eV and ~10-~ torr. The interpretation of single- and double-resonance peak heights under these conditions is discussed qualitatively, and the double resonance spectra are used to design relative rates to the observed reactions. The chemistry is strikingly different from that at higher electron energy. These results are discussed in some detail. R C Dunbar et al, J Chem Phys, 56 (8), 15th ApriI 1972,3794-3798. 33 921. Metallic hydride targets for the production of neutrons. Operation
and preparation. (France) Mechanisms affecting the performance of hydride targets for the production of neutrons are investigated. The principal cause of target deterioration with time, is the dilution of tritium in the target by deuterium from the ion beam. A simplified theoretical approach is described which allows calculation of the half-life of any target and which gives results in good agreement with experimental values. The design of an apparatus for the preparation of tritium targets is described. After volatilization of the metal, the target is held under a vacuum of lo--’ torr until the impregnation of the layer. J DCtaint et al, Le Vide, 26 (154), July-Aug-Sepf-Ott, 1971, 143-149 (in French). 33 922. Path separation type, non-magnetic mass spectrometer.
(Japan) A non-magnetic mass spectrometer of the path separation type, with parallel plane electrodes was studied. The sensor consisted of two side plates with a rectangular box inserted between them. A square wave negative rf voltage is applied to the box electrode which has two windows with grids on both sides. A collimated ion beam injected into the space between the first side plate and the box, along the tube axis, is accelerated to the box and after passing through the box is then decelerated between the box and the other side plate. Composite ions in the beam disperse in directions corresponding to mass number and only ions directed along the tube axis can reach the collector through the exit collimator. To obtain mass spectra, the frequency of the rf voltage was swept. Resolving power was 27 and current efficiency was about 4 per cent which was in good agreement with expected values. The resolving power is independent of the velocity distribution of the ions and the theoretically possible efficiency would be 50 per cent. Methods of improving the performance are discussed. F Kanematsu and H Mhna, J Vat Sot Japan, 14 (12), 1971,431-435 (in Japanese). 33 923. Transistorized
high-frequency generator for monopole mass spectrometer. (USSR) Circuit diagram of a high-frequency transistorized generator for a monopole mass spectrometer is described. The generator employs a feedback circuit for stabilization of output voltage; crystal stabilization of oscillator frequency; and it provides manual and automatic scanning of the output voltage from 5 to 1500 V on frequencies of l-3 MHz. L F Berzin, Prib Tekh Eksper, No 5,1971, 120-122 (in Russian). 33 924. Ion source of mass spectrometer MI-1305 for investigations at
high temperatures. (USSR) An ion source with a heater for investigation of composition of a gas phase in equilibrium with a condensed phase heated to 2000°K is described. A movable diaphragm is placed between the Knudsen cell and the cooling system. K Skudlarskl, Prib Tekh Eksper, No 2, 1971,268-269 (in Russian). 33 925. Formation of H- ions by charge exchange of 1.540
keV protons
in thick streams of Li, Na, K and Mg vapours. (USSR) The formation of negative hydrogen ions by charge exchange of 1.5-10 keV protons in thick streams of Na, Li, K and Mg vapours is studied experimentally in a vacuum system. It is found that Na