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Surface contaminant detector. (USA)
Classified abstracts 2 2 4 9 - 2 3 5 2 Classified abstracts 2 2 4 9 - 2 2 5 6 on this page
Editor's n o t e The label immediately following the title of each item denotes country or origin of publication, and that at the end of each abstract indicates country of origin of work (where known).
I. G e n e r a l v a c u u m s c i e n c e and e n g i n e e r i n g 11. GASES A N D SOLIDS 11 2249. Charge exchange in zinc-neon. (USA) Excitation of the 4d and 5p levels of Zn § by charge exchange between Ne + and Zn was investigated. From measured electron temperature and line intensity ratios it was concluded that charge exchange is the dominant mechanism for populating the 4d 2 Ds/2 level of Zn+. Comparison of Z n - N e and Z n - A r results imply the same conclusion. No evidence for charge exchange as the dominant pumping mechanism for the 5p2Pu2, 5p2/z, or 4dZD3/2 levels was obtained. D L Chubb, J Appl Phys, 47 (6), 1976, 2462 2466. 11 2250. Refractive index profiles induced by ion implantation into silica (GB) Ion implantation of silica glass increases the refractive index. For ions of H +, He + , Li +, B +, Na +, Ar +, Bi + the maximum index change in the depth profile is normally between 1 and 2%. Such changes are consistent with compaction of the lattice which results from radiation damage. Greater changes are recorded for nitrogen implantation of silica; in the present work values up to 6 % have been noted. This is interpreted as a chemical change in the structure of the glass. The measurements of the refractive index as a function of implantation depth were made by a technique of ellipsometry combined with a chemical stripping of surface layers. Such detailed analyses of the refractive index profile have implications for the formation of optical waveguides in silica as well as the mechanisms involved in the modification of refractive index. A P Webb and P D Townsend, J Phys D: Appl Phys, 9 (9), 1976, 1343-1354. 11 2251. Effect of adsorbed films on friction of AIzO3-metal systems. (USA) The kinetic fraction of polycrystalline AI/O3 sliding on Cu, Ni, and Fe in ultrahigh vacuum was studied as a function of the surface chemistry of the metal. Clean metal surfaces were exposed to O2, C12, CzH4, and CzH3C[, and the change in friction due to the adsorbed species was observed. Auger electron spectoscopy assessed the elemental composition of the metal surface. It was found that the systems exposed to Clz exhibited low friction, interpreted as the van der Waals force between the AlzO3 and metal chloride. The generation of metal oxide by oxygen exposures resulted in an increase in friction, interpreted as due to strong interfacial bonds by reaction of metal oxide with AlzOa to form the complex oxide (spinel). The only effect of C2H4 was to increase the fraction of the Fe system, but C2H3C[ exposures decreases friction in both Ni and Fe systems, indicating the dominance of the chlorine over the ethylene complex on the surface. S V Pepper, J ApplPhys, 47 (6), 1976, 2579-2583. 11 2252. Field desorption of helium and neon. (USA) Employing our energy-focused atom-probe FIM, providing high resolution and freedom from artifacts, we have obtained complete crystallographic distribution of helium and neon field adsorbed on W, Mo, Ta, Rh, Ir, Pt and Re. In addition we have determined the abundance of metal-helium and metal-neon molecular ions of these metals as obtained by field evaporation. The dependence of the relative abundance of metal-helium molecule ions upon the substrate temperature and the crystallographic surface area is established. Whereas the triply charged W, Ta, Mo, and Re helides and doubly charged helides of other metals are predominant molecular ion species in pulsed field evaporation, metal-neides are formed with a
probability of less than 10 3. We were unable to confirm with our precise instrument a high probability of IrHe + + + and IrNe + + as indirectly deduced by Panitz. We are convinced that the high abundance of IrNe + + and IrNe +++ reported by Waugh from observations with a time-gated imaging field desorption microscope must also be artifacts. S V Krishnaswamy et al, J Vac Sci Technol, 13 (3), 1976, 555-669. 1t 2253. Measurement of sorption rate for nitrogen by zirconium at elevated temperature. (USA) A study has been made of sorption rate for nitrogen by zirconium in the range of 10-2-10 Pa and 600~176 by means of the constantvolume method. Depending on nitrogen pressure, two types of rate law were observed; i.e., the linear and parabolic rate laws in the range of lower and higher pressure, respectively. The properties of nitrogen sorption under the constant-volume condition are discussed by use of Wagner's model involving simultaneous formation of compact scale and the dissolution of nitrogen atoms into the metal bulk. (Japan) M Nagasaka, J Vac Sci Technol, 13 (3), 1976, 676-679. 11 2254. Surface contaminant detector. (USA) The construction and operation of a surface contaminant detector are described. The sensitivity of the solid-phase bonding of gold-to-gold to adsorbed organic matter is used in this instrument to indicate the contamination level in the environment or on the surfaces of metallic solids. The detection range appears to be unlimited. The behavior of the instrument under various conditions is described for over lO s tests with the same pair of gold contacts. Some of the applications for the portable detector are the testing of clean benches, clean rooms, storage containers, and the surfaces of metallic parts. R E Cuthrell and D W Tipping, Roy Sci lnstrum, 47 (5), 1976, 595 597.
12. GASEOUS ELECTRONICS 12 2255. Wall depletion effect of population at upper laser level on optical gain in CO2-He waveguide lasers. (USA) The wall depletion effect of C O 2 molecules at the excited (00~ level has been taken into consideration for the calculation of the optical gain of CO2-He waveguide lasers having a circular discharge tube and a parallel-plate discharge tube. The simplified equations for obtaining the wall depletion rate for these two discharge tubes are presented and they are found to be in good agreement with the exact values. The numerical calculation revealed the presence of an optimum radius and height of discharge tubes as a function of gas pressure, mixing ratio of the laser gases, tubing materials, and the shape of the discharge tubes, The numerically computed smallsignal gain has been found in good agreement with the experimentally observed values. (Japan) H Shirahata and T Fujioka, J App Phys, 47 (6), 1976, 2452-2458. 12 2256. Multiple preionization discharge TEA COz laser (USA). A new concept in utilizing preionization in the TEA CR2 laser is presented. The variable adjustment of the delay between the proionization and the main discharge in a pin-grid double discharge TEA COz laser permits the use of low He concentrations (_<60~), and different CO2/(CO2 + N2) ratios (ranging from 1 to 0) at relatively high main discharge storage energy density (150 J/l.). The addition of a different preionization source (Lamberton-Pearson type) to this laser type leads to further increase in overall performance. This permits a completely variable TEA COg laser operation over the gas mixture [100-45 % He, and CO2/(COz + N2) ratio from 1 to
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Editor's n o t e The label immediately following the title of each item denotes country or origin of publication, and that at the end of each abstract indicates country of origin of work (where known).
I. G e n e r a l v a c u u m s c i e n c e and e n g i n e e r i n g 11. GASES A N D SOLIDS 11 2249. Charge exchange in zinc-neon. (USA) Excitation of the 4d and 5p levels of Zn § by charge exchange between Ne + and Zn was investigated. From measured electron temperature and line intensity ratios it was concluded that charge exchange is the dominant mechanism for populating the 4d 2 Ds/2 level of Zn+. Comparison of Z n - N e and Z n - A r results imply the same conclusion. No evidence for charge exchange as the dominant pumping mechanism for the 5p2Pu2, 5p2/z, or 4dZD3/2 levels was obtained. D L Chubb, J Appl Phys, 47 (6), 1976, 2462 2466. 11 2250. Refractive index profiles induced by ion implantation into silica (GB) Ion implantation of silica glass increases the refractive index. For ions of H +, He + , Li +, B +, Na +, Ar +, Bi + the maximum index change in the depth profile is normally between 1 and 2%. Such changes are consistent with compaction of the lattice which results from radiation damage. Greater changes are recorded for nitrogen implantation of silica; in the present work values up to 6 % have been noted. This is interpreted as a chemical change in the structure of the glass. The measurements of the refractive index as a function of implantation depth were made by a technique of ellipsometry combined with a chemical stripping of surface layers. Such detailed analyses of the refractive index profile have implications for the formation of optical waveguides in silica as well as the mechanisms involved in the modification of refractive index. A P Webb and P D Townsend, J Phys D: Appl Phys, 9 (9), 1976, 1343-1354. 11 2251. Effect of adsorbed films on friction of AIzO3-metal systems. (USA) The kinetic fraction of polycrystalline AI/O3 sliding on Cu, Ni, and Fe in ultrahigh vacuum was studied as a function of the surface chemistry of the metal. Clean metal surfaces were exposed to O2, C12, CzH4, and CzH3C[, and the change in friction due to the adsorbed species was observed. Auger electron spectoscopy assessed the elemental composition of the metal surface. It was found that the systems exposed to Clz exhibited low friction, interpreted as the van der Waals force between the AlzO3 and metal chloride. The generation of metal oxide by oxygen exposures resulted in an increase in friction, interpreted as due to strong interfacial bonds by reaction of metal oxide with AlzOa to form the complex oxide (spinel). The only effect of C2H4 was to increase the fraction of the Fe system, but C2H3C[ exposures decreases friction in both Ni and Fe systems, indicating the dominance of the chlorine over the ethylene complex on the surface. S V Pepper, J ApplPhys, 47 (6), 1976, 2579-2583. 11 2252. Field desorption of helium and neon. (USA) Employing our energy-focused atom-probe FIM, providing high resolution and freedom from artifacts, we have obtained complete crystallographic distribution of helium and neon field adsorbed on W, Mo, Ta, Rh, Ir, Pt and Re. In addition we have determined the abundance of metal-helium and metal-neon molecular ions of these metals as obtained by field evaporation. The dependence of the relative abundance of metal-helium molecule ions upon the substrate temperature and the crystallographic surface area is established. Whereas the triply charged W, Ta, Mo, and Re helides and doubly charged helides of other metals are predominant molecular ion species in pulsed field evaporation, metal-neides are formed with a
probability of less than 10 3. We were unable to confirm with our precise instrument a high probability of IrHe + + + and IrNe + + as indirectly deduced by Panitz. We are convinced that the high abundance of IrNe + + and IrNe +++ reported by Waugh from observations with a time-gated imaging field desorption microscope must also be artifacts. S V Krishnaswamy et al, J Vac Sci Technol, 13 (3), 1976, 555-669. 1t 2253. Measurement of sorption rate for nitrogen by zirconium at elevated temperature. (USA) A study has been made of sorption rate for nitrogen by zirconium in the range of 10-2-10 Pa and 600~176 by means of the constantvolume method. Depending on nitrogen pressure, two types of rate law were observed; i.e., the linear and parabolic rate laws in the range of lower and higher pressure, respectively. The properties of nitrogen sorption under the constant-volume condition are discussed by use of Wagner's model involving simultaneous formation of compact scale and the dissolution of nitrogen atoms into the metal bulk. (Japan) M Nagasaka, J Vac Sci Technol, 13 (3), 1976, 676-679. 11 2254. Surface contaminant detector. (USA) The construction and operation of a surface contaminant detector are described. The sensitivity of the solid-phase bonding of gold-to-gold to adsorbed organic matter is used in this instrument to indicate the contamination level in the environment or on the surfaces of metallic solids. The detection range appears to be unlimited. The behavior of the instrument under various conditions is described for over lO s tests with the same pair of gold contacts. Some of the applications for the portable detector are the testing of clean benches, clean rooms, storage containers, and the surfaces of metallic parts. R E Cuthrell and D W Tipping, Roy Sci lnstrum, 47 (5), 1976, 595 597.
12. GASEOUS ELECTRONICS 12 2255. Wall depletion effect of population at upper laser level on optical gain in CO2-He waveguide lasers. (USA) The wall depletion effect of C O 2 molecules at the excited (00~ level has been taken into consideration for the calculation of the optical gain of CO2-He waveguide lasers having a circular discharge tube and a parallel-plate discharge tube. The simplified equations for obtaining the wall depletion rate for these two discharge tubes are presented and they are found to be in good agreement with the exact values. The numerical calculation revealed the presence of an optimum radius and height of discharge tubes as a function of gas pressure, mixing ratio of the laser gases, tubing materials, and the shape of the discharge tubes, The numerically computed smallsignal gain has been found in good agreement with the experimentally observed values. (Japan) H Shirahata and T Fujioka, J App Phys, 47 (6), 1976, 2452-2458. 12 2256. Multiple preionization discharge TEA COz laser (USA). A new concept in utilizing preionization in the TEA CR2 laser is presented. The variable adjustment of the delay between the proionization and the main discharge in a pin-grid double discharge TEA COz laser permits the use of low He concentrations (_<60~), and different CO2/(CO2 + N2) ratios (ranging from 1 to 0) at relatively high main discharge storage energy density (150 J/l.). The addition of a different preionization source (Lamberton-Pearson type) to this laser type leads to further increase in overall performance. This permits a completely variable TEA COg laser operation over the gas mixture [100-45 % He, and CO2/(COz + N2) ratio from 1 to
551