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Study of the adsorption of gases on metals by the Auger process
Classified
abstracts
280-292 16 of gases on metals by the Auger process.
280. Study of the adsorption (USA)
The apparatus under construction to measure the degree of surface coverage using the Auger process is described. It will use an electron impact helium ion source, leading to a cylindrical lens which focuses the ions onto the target. The target is a single crystal tungsten ribbon mounted on two heating leads which pass directly into a liquid nitrogen cooling bath. A schematic of the adsorption-desorption experiment is included and the experimental technique is illustrated. D Alpert, Rep NASA-CR-75681; (Illinois Univ Urbana, Coordinated
18. Gaseous
R-286; AD-632596; Science Lab).
April
18 It is concluded that there are at least sixteen variables affecting breakdown in vacuum. Traditional methods of experimenting by varying one parameter at a time would take years to amass the data on which a cohesive theory could be formulated. A pilot experiment was set up based on the statistical approach to experimental design to evaluate the relative importance of each of the variables. The pilot experiment is a partial replica of a two-level full factorial design. It is expected that sufficient information will be collected to permit the elimination of variables having minor effects and to permit a more comprehensive design for the final experiment. Jan 1966 (Army
18 in potassium
and mercury.
(USA)
The resistivity of superheated potassium and mercury vapour was measured. Substantial heating of the gas by the discharge was avoided by flowing the gas through the discharge region. The resistivity of potassium gas at 7.8 Torr pressure, 870°K and 1 A/cm2 is 2.2 ohm cm. The resistivity of mercury gas at 14 Torr, 870°K and 0.67 A/cm2 is 10 ohm cm. The resistance was primarily due to short range electron/neutral atom collisions. The cross section for this process as calculated from the resistivity is 1.5 x lo-” cm” for potassium and 2.5 X 1O~l’ cm* for mercury. C A Guderjahn, Rep AId5-120; AFORS-65-1914; A 0628187, Jul_v I965 (Atomics
International,
Canoga Park, Cal(f). 18
283. Investigation An experimental
of high power gaseous electronics.
(USA)
technique is described for obtaining reproducible clean-up measurements in high power microwave duplexer discharges under controlled conditions. A basic clean-up rate is defined as the number of molecules sorbed per cm3 of discharge/square root of average incident power. Data is given for the clean-up of inert gases in quartz; hydrogen in 7070 glass, quartz, copper, nickel, molybdenum and kovar; and oxygen and bromine in kovar. It was found that life time of duplexers increases with the square of the ratio of gas volume to discharge area and with the square of the pressure range over which a tube remains operable. Life time is also inversely proportional to peak power and to the square of the duty cycle. H S Maddix, Rep AD-629537, Burlington, Mass). 284. A high resolution research. (USA)
Feb 1966 (Microwave
secondary
emission
Associates
spectrometer
Znc
18 : 39 for surface
The possibility of using secondary emission in surface research and the apparatus developed for this research are discussed. The secondary electrons were divided into two groups: primary electrons scattered (elastically or inelastically) from the surface, and electrons excited from the surface by the primaries. It is suggested that the following main areas can be investigated using the elastically scattered electrons: (1) the excitation of the vibrational states of adsorbed gas species on the surface; (2) the electronic transitions of the adsorbed atoms on surfaces; (3) the plasmon excitation by electron impact. Details of the apparatus constructed for high resolution studies are given and schematic diagrams are included. The operation of the monochromator/analyzer system is described and the operating characteristics are shown. Measurements obtained on the (100) surface of a tungsten single crystal ribbon are discussed and the energy distribution of secondary electrons from a contaminated 110
Univ Urbana, Coordinated
Science Lab).
18 285. High frequency discharge in a ring electrode. (USSR) The mechanism of the plasma configuration excitation by a ring electrode hf field was investigated at pressures of 2 x 10m2to 1 torr. A D Andreev et al, Zh Tekh Fiz, 36 (9), Russian).
Sept 1966, 1636-1638
(in
18 regions of the
286. Energy and angle distribution of ions in various cathode in a higb voltage Penning discharge. (USSR)
281. Design of a high voltage breakdown in vacuum experiment. (USA)
282. Flowing gas discharges
(Illinois
1966.
electronics
M N Cbrepta et al, Rep ECOM-2655; AD-628042, Electronics Labs, Fort Monmouth, NJ).
surface, from the surface after exposure to nitrogen and hydrogen and from clean tungsten, are presented. D Alpert, Rep NASA-CR-75681; R-286; AD632596; April 1966
The properties of the Penning discharge were studied with particular reference to the pumping action. It was found that residual gas ions bombard only a narrow area at the cathode centre in the direction perpendicualr to the cathode surface with energies dependent on the pressure. Experiments were performed at the 1O-4 to 1O-Btorr range. 0 K Kurbatov, Zh Tekh Fiz, 36 (9)) Sept 1966,1665-1668 (in Russian). 287. Atomic beam Ionizer as a source of polarized ions.
18 :33 (USSR)
The design of the Zinchenko type hydrogen ionizer with high efficiency (about 4.5 x lo-*) is described. It operates at 1O-8 torr with an oxide cathode as the electron source and hydrogen atom beam intensity is measured by an ionization gauge. 0 I Ekhichev et al, Zh Tekh Fiz, 36 (9), Sept 1966, 1681-1684 (in Russian). 288. Two mechanisms crystals. (USSR)
of photo-stimulated
electron
emission
18 by ion
It is shown that the photo-thermal mechanism of the photo-stimulated electron emission from F-centres of ion crystals is well established only when ion crystals are in a gas atmosphere and that the photoionization mechanism exists alone under high vacuum conditions. A N Belkind et al, Izv Akad Nauk SSSR, Ser Fiz 30 (9), Sept 1966, 1448-1450
(in Russian).
18 :30 289. The effect of backing material on photo-emf in CdTe films. (USSR)
It is known that photo-emf of CdTe thin films depends on the backing material and its temperature during vacuum condensation of the films. Experiments showed that, for AlBOS backing, the CdTe photo-emf more than double that for glass backing. The backing temperature dependence is described. L S Palatnik and V K Sorokin, Fiz Tverd Tela, 8 (9), Sept 1966,27952796 (in Russian). 18 290. Dependence of secondary electron emission and electron elastic reflection on thickness of barium oxide film on tungsten in the case of low energy primary electrons. (USSR)
For primary electrons with energies 3 to 50 eV the depth of secondary electron emission is 16 monolayers and it is not dependent on the primary electron energy. Electron elastic reflection depth is about 5 monolayers and it is not dependent on the primary electron energies in the range 5 to 17 eV. All experiments were made at IO+ torr and carefully baked polycrystal- tungsten was employed as the backing for BaO layers. A R Shul’man and N P Bazhanova, 2797-2798 (in Russian).
Fiz Tverd Tela, 8 (9), Sept. I966
18 :33 291. Measurement of cathode oxide coating electroconductivity and the coating work functions, using a probe. (USSR) Work function of the cathode oxide coatings was found by measuring the electroconductivity of the oxides and its changes in a magnetic field. Advantages of the described method are: the temperature of the probe and the oxide are identical; and the probe position determinations have only slight influence on experimental error. Typical characteristics are given and compared with those obtained by Schottky method. E M Sher, Radiotekh Elektron, 11 (9), Sept 1966, 1721-1723 (in Russian). 18 292. Secondary electron emission of alloys of zirconium and hafnimn with rhenium. (USSR) The influence of the composition of Zr-Re and Hf-Re alloys on the
abstracts
280-292 16 of gases on metals by the Auger process.
280. Study of the adsorption (USA)
The apparatus under construction to measure the degree of surface coverage using the Auger process is described. It will use an electron impact helium ion source, leading to a cylindrical lens which focuses the ions onto the target. The target is a single crystal tungsten ribbon mounted on two heating leads which pass directly into a liquid nitrogen cooling bath. A schematic of the adsorption-desorption experiment is included and the experimental technique is illustrated. D Alpert, Rep NASA-CR-75681; (Illinois Univ Urbana, Coordinated
18. Gaseous
R-286; AD-632596; Science Lab).
April
18 It is concluded that there are at least sixteen variables affecting breakdown in vacuum. Traditional methods of experimenting by varying one parameter at a time would take years to amass the data on which a cohesive theory could be formulated. A pilot experiment was set up based on the statistical approach to experimental design to evaluate the relative importance of each of the variables. The pilot experiment is a partial replica of a two-level full factorial design. It is expected that sufficient information will be collected to permit the elimination of variables having minor effects and to permit a more comprehensive design for the final experiment. Jan 1966 (Army
18 in potassium
and mercury.
(USA)
The resistivity of superheated potassium and mercury vapour was measured. Substantial heating of the gas by the discharge was avoided by flowing the gas through the discharge region. The resistivity of potassium gas at 7.8 Torr pressure, 870°K and 1 A/cm2 is 2.2 ohm cm. The resistivity of mercury gas at 14 Torr, 870°K and 0.67 A/cm2 is 10 ohm cm. The resistance was primarily due to short range electron/neutral atom collisions. The cross section for this process as calculated from the resistivity is 1.5 x lo-” cm” for potassium and 2.5 X 1O~l’ cm* for mercury. C A Guderjahn, Rep AId5-120; AFORS-65-1914; A 0628187, Jul_v I965 (Atomics
International,
Canoga Park, Cal(f). 18
283. Investigation An experimental
of high power gaseous electronics.
(USA)
technique is described for obtaining reproducible clean-up measurements in high power microwave duplexer discharges under controlled conditions. A basic clean-up rate is defined as the number of molecules sorbed per cm3 of discharge/square root of average incident power. Data is given for the clean-up of inert gases in quartz; hydrogen in 7070 glass, quartz, copper, nickel, molybdenum and kovar; and oxygen and bromine in kovar. It was found that life time of duplexers increases with the square of the ratio of gas volume to discharge area and with the square of the pressure range over which a tube remains operable. Life time is also inversely proportional to peak power and to the square of the duty cycle. H S Maddix, Rep AD-629537, Burlington, Mass). 284. A high resolution research. (USA)
Feb 1966 (Microwave
secondary
emission
Associates
spectrometer
Znc
18 : 39 for surface
The possibility of using secondary emission in surface research and the apparatus developed for this research are discussed. The secondary electrons were divided into two groups: primary electrons scattered (elastically or inelastically) from the surface, and electrons excited from the surface by the primaries. It is suggested that the following main areas can be investigated using the elastically scattered electrons: (1) the excitation of the vibrational states of adsorbed gas species on the surface; (2) the electronic transitions of the adsorbed atoms on surfaces; (3) the plasmon excitation by electron impact. Details of the apparatus constructed for high resolution studies are given and schematic diagrams are included. The operation of the monochromator/analyzer system is described and the operating characteristics are shown. Measurements obtained on the (100) surface of a tungsten single crystal ribbon are discussed and the energy distribution of secondary electrons from a contaminated 110
Univ Urbana, Coordinated
Science Lab).
18 285. High frequency discharge in a ring electrode. (USSR) The mechanism of the plasma configuration excitation by a ring electrode hf field was investigated at pressures of 2 x 10m2to 1 torr. A D Andreev et al, Zh Tekh Fiz, 36 (9), Russian).
Sept 1966, 1636-1638
(in
18 regions of the
286. Energy and angle distribution of ions in various cathode in a higb voltage Penning discharge. (USSR)
281. Design of a high voltage breakdown in vacuum experiment. (USA)
282. Flowing gas discharges
(Illinois
1966.
electronics
M N Cbrepta et al, Rep ECOM-2655; AD-628042, Electronics Labs, Fort Monmouth, NJ).
surface, from the surface after exposure to nitrogen and hydrogen and from clean tungsten, are presented. D Alpert, Rep NASA-CR-75681; R-286; AD632596; April 1966
The properties of the Penning discharge were studied with particular reference to the pumping action. It was found that residual gas ions bombard only a narrow area at the cathode centre in the direction perpendicualr to the cathode surface with energies dependent on the pressure. Experiments were performed at the 1O-4 to 1O-Btorr range. 0 K Kurbatov, Zh Tekh Fiz, 36 (9)) Sept 1966,1665-1668 (in Russian). 287. Atomic beam Ionizer as a source of polarized ions.
18 :33 (USSR)
The design of the Zinchenko type hydrogen ionizer with high efficiency (about 4.5 x lo-*) is described. It operates at 1O-8 torr with an oxide cathode as the electron source and hydrogen atom beam intensity is measured by an ionization gauge. 0 I Ekhichev et al, Zh Tekh Fiz, 36 (9), Sept 1966, 1681-1684 (in Russian). 288. Two mechanisms crystals. (USSR)
of photo-stimulated
electron
emission
18 by ion
It is shown that the photo-thermal mechanism of the photo-stimulated electron emission from F-centres of ion crystals is well established only when ion crystals are in a gas atmosphere and that the photoionization mechanism exists alone under high vacuum conditions. A N Belkind et al, Izv Akad Nauk SSSR, Ser Fiz 30 (9), Sept 1966, 1448-1450
(in Russian).
18 :30 289. The effect of backing material on photo-emf in CdTe films. (USSR)
It is known that photo-emf of CdTe thin films depends on the backing material and its temperature during vacuum condensation of the films. Experiments showed that, for AlBOS backing, the CdTe photo-emf more than double that for glass backing. The backing temperature dependence is described. L S Palatnik and V K Sorokin, Fiz Tverd Tela, 8 (9), Sept 1966,27952796 (in Russian). 18 290. Dependence of secondary electron emission and electron elastic reflection on thickness of barium oxide film on tungsten in the case of low energy primary electrons. (USSR)
For primary electrons with energies 3 to 50 eV the depth of secondary electron emission is 16 monolayers and it is not dependent on the primary electron energy. Electron elastic reflection depth is about 5 monolayers and it is not dependent on the primary electron energies in the range 5 to 17 eV. All experiments were made at IO+ torr and carefully baked polycrystal- tungsten was employed as the backing for BaO layers. A R Shul’man and N P Bazhanova, 2797-2798 (in Russian).
Fiz Tverd Tela, 8 (9), Sept. I966
18 :33 291. Measurement of cathode oxide coating electroconductivity and the coating work functions, using a probe. (USSR) Work function of the cathode oxide coatings was found by measuring the electroconductivity of the oxides and its changes in a magnetic field. Advantages of the described method are: the temperature of the probe and the oxide are identical; and the probe position determinations have only slight influence on experimental error. Typical characteristics are given and compared with those obtained by Schottky method. E M Sher, Radiotekh Elektron, 11 (9), Sept 1966, 1721-1723 (in Russian). 18 292. Secondary electron emission of alloys of zirconium and hafnimn with rhenium. (USSR) The influence of the composition of Zr-Re and Hf-Re alloys on the