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Electron-beam-controlled n2 infrared laser
Classified
abstracts
1899-l
907
samples of Au on bulk glass showed no reactions. The rate of reduction of the oxide proceeds with an activation energy of approximately 26 kcal/mole. E I Alessandrini et al, J Vuc Sri Techno/, 13 (I), 1976, 53-57. II
1899. Correlation between the composition profile and electrical conductivity of the thermal and anodic oxides of I&b. (USA) The differences between the electrical conductivity of thermal and anodic oxides of InSb have been reported previously. In this paper these differences are correlated with the chemical compositional profiles of the two oxides. The anodic oxide is shown to be an iridium oxide containing a large concentration of Sb. while the thermal oxide contains a relatively low concentration of Sb. but has an Sb-rich layer between the indium oxide and the InSb. By postformation annealing of the anodic oxide or application of a large electric field to the thermal oxide, the oxide compositions are changed. These changes are accompanied by a corresponding change in the electrical conductivity of the oxide. From these data and the changes in the Auger line shape for In, it appears that Sb-In bonding in the oxide is related to the change of conductivity. C W Wilmsen, J Vat Sci Technol, 13 (I ), 1976. 64-67.
I2
1903. Electron-beam-controlled
N1 infrared laser. (USA)
Laser action in NL on the first positive system (f33fI,-A3E,+) has been obtained in an electron-beam-controlled discharge. Pressures of up 200 Torr (limited by the sustainer voltage available) were used resulting in a maximum output of 30-kW 2-mJ pulses at an efficiency of 0.01 %. The addition of a small amount (-I Torr) of SFr, resulted in a doubling of the output power and energy. L A Newman and T A DeTemple, J Appl Phys, 47 (I ), 1976. 376-377.
1904. Photoionization cross sections of metal vapors below 50 nm: an apparatus for their measurement. (USA) An apparatus built for the measurement of photoionization cross sections of metallic vapors in the 30-100-nm wavelength region is described. The performance was tested by measurements of cross sections in the region of the window resonances in argon. Results in agreement with those of Madden, Codling, and Ederer were obtained. R D Driver and J E C Wheaton, Appl Opt, 15 (3). 1976, 700-732. I2 1905.
Laser
wavelength
comparison by high resolution interferometry.
(USA) 12. GASEOUS
ELECTRONICS I2
1900. ac photoresponse of a large-area junction. (USA)
imaging CdS/CdTe
hetero-
Experimental data are presented for the photosensor-substrate structure presently used with the ac liquid-crystal projection light valve. This structure consists of a thin film (sputter deposited) of n-type CdS on which is evaporated a thin film of p-type CdTe. In an earlier publication, a model was presented which describes the photosensitivity of this structure in terms of the depletion-width photocapacity of the charge-storage diode formed by these two coatings. The experimental data presented here correlate well with this model. Among the data presented are data on light-valve display, photosensor gray scale, and response time. The response-time data are of particular interest because they show that the projection-light-valve photosensor is capable of operation at near-TV rates. The agreement of the experimental data with model and extrapolation from the model imply that large improvements in sensitivity and response time are still quite possible.
High resolution interferometry has been used to determine the wavelength ratio between two molecularly stabilized He-Ne lasers. one locked to a methane absorption at 3.39 pm and the other locked to the k peak of ‘ZslZ at 633 nm. An optical beat frequency technique gave fractional orders while a microwave sideband method yielded the integer parts. Conventional (third derivative) peak seeking servoes stabilized both laser and cavity lengths. Reproducibility of the electronic control system and optics was a few parts in IO”, while systematic errors associated with curvature of the cavity mirrors limited the accuracy of the wavelength ratio measurement to 2 parts in IO“‘. The measured wavelength ratio of the methane stabilized He-Ne laser at 3.39 pm (P(7) line, Y~ band) to the lz91r (k peak) stabilized He-Ne laser at 633 nm was 5.359 049 260 6 (0.000 2 ppm). This ratio agrees with that calculated from the (lower accuracy) results of earlier wavelength measurements made relative to the 86Kr standard. Its higher accuracy thus permits a provisional extension of the frequency scale based on the cesium oscillator into the visible spectrum. H P Layer et al, Appl Opr, 15 (3). 1976, 734-743.
L M Fraas et al, J Appl Phys, 47 (2), 1976,5&l-590.
21. PUMPS
12 1901. Ultraviolet photoemission study of cesium oxide films on GaAs. (USN
1906. A new adsorption adsorbent. (USSR)
Ultraviolet photoemission energy distribution curves (EDC’s) have been measured from a GaAs (110) surface covered with Cs oxide layers of varying thickness. There is no evidence of emission from Cs oxide in the EDC’s from GaAs with a surface treatment that produces optimum yield, but structure characteristic of the GaAs is present in the EDC’s. However. EDC’s characteristic of bulk Cs oxide were measured from GaAs with a thick (at least several molecular layers) Cs oxide surface layer, but no structure characteristic of the GaAs was present in the EDC’s. Compared to the GaAs with the optimum surface treatment, this thick Cs oxide film produced yield spectra having a higher photoemission threshold and a lower yield throughout the photon energy range studied (I .4< /rv< I I .6 eV). These measurements indicate that the Cs oxide layer required for activation of GaAs to negative electron affinity is so thin that the Cs oxide layer does not have bulk properties which can be detected by photoemission. Measurements similar to those reported here on narrower-band-gap III-V alloys should determine if the thickness of the Cs oxide layer required for activation increases with decreasing band gap or is independent of band gap. P E Gregory and W E Spicer, J ApplPhys, 47 (2), 1976,510-517.
1902. Radial protiles of upper-laser-level Arll laser. (USA)
12 emission in an oscillating
Radial profiles of the emission from upper-laser-level ions have been investigated in an oscillating ArII laser and a significant dip in the tube center is observed. (Japan)
T Ihjima et al, J Appl Phys, 47 (I), 1976.383-384. 354
AND
PUMP
FLUIDS
vacuum pump with moving regenerating
Assuming that the diffusion coefficient is constant, the pumping speed of a vacuum adsorption pump with circulating sorbent is calculated and the distribution of the concentration of adsorbed gas in the adsorbent is determined. A model of the operation of such a pump and its design are presented. The calculated dependence of pumping speed on the gas pressure is compared with the experimental one obtained by using aluminosilicate catalyst as an adsorbent. The total amount of adsorbent was 100 g, 30 g was in the adsorption zone. The period of adsorbent transport was 15.5 hours. The ratio of the pressures in the desorption and adsorption zones was 100. The lower value of the experimentally determined pumping speed in comparison with the calculated one is explained by the method of operation, at which the adsorbent temperature in the adsorption chamber does not reach the equilibrium value.
L N Roxanov and L A Kuzinits, Probl of Atomic Science and Technol, Ser P~JJJSand Technol of H~IJ Vacuum, Coil, No I. Kharkov 1973, 33-39 (in Russian). 1.
1907. Vacuum magnetic-discharge
pumps with lower weight. (US&
It is shown that the placing of the magnetic system into the vacuum envelope of magnetic-discharge pumps results in decreasing of their weight coefficient from 0.5 to 0.2 kg 1-i sec. Anisotropic magnets based on barium hexaferrite and characterized by absence of additional demagnetization after repeated heating and cooling, fast degassing in vacuum, high coercive force and low price, have been used. Two types of magnetic system placed in vacuum are presented. For magnetic-discharge pump with high pumping speed above
abstracts
1899-l
907
samples of Au on bulk glass showed no reactions. The rate of reduction of the oxide proceeds with an activation energy of approximately 26 kcal/mole. E I Alessandrini et al, J Vuc Sri Techno/, 13 (I), 1976, 53-57. II
1899. Correlation between the composition profile and electrical conductivity of the thermal and anodic oxides of I&b. (USA) The differences between the electrical conductivity of thermal and anodic oxides of InSb have been reported previously. In this paper these differences are correlated with the chemical compositional profiles of the two oxides. The anodic oxide is shown to be an iridium oxide containing a large concentration of Sb. while the thermal oxide contains a relatively low concentration of Sb. but has an Sb-rich layer between the indium oxide and the InSb. By postformation annealing of the anodic oxide or application of a large electric field to the thermal oxide, the oxide compositions are changed. These changes are accompanied by a corresponding change in the electrical conductivity of the oxide. From these data and the changes in the Auger line shape for In, it appears that Sb-In bonding in the oxide is related to the change of conductivity. C W Wilmsen, J Vat Sci Technol, 13 (I ), 1976. 64-67.
I2
1903. Electron-beam-controlled
N1 infrared laser. (USA)
Laser action in NL on the first positive system (f33fI,-A3E,+) has been obtained in an electron-beam-controlled discharge. Pressures of up 200 Torr (limited by the sustainer voltage available) were used resulting in a maximum output of 30-kW 2-mJ pulses at an efficiency of 0.01 %. The addition of a small amount (-I Torr) of SFr, resulted in a doubling of the output power and energy. L A Newman and T A DeTemple, J Appl Phys, 47 (I ), 1976. 376-377.
1904. Photoionization cross sections of metal vapors below 50 nm: an apparatus for their measurement. (USA) An apparatus built for the measurement of photoionization cross sections of metallic vapors in the 30-100-nm wavelength region is described. The performance was tested by measurements of cross sections in the region of the window resonances in argon. Results in agreement with those of Madden, Codling, and Ederer were obtained. R D Driver and J E C Wheaton, Appl Opt, 15 (3). 1976, 700-732. I2 1905.
Laser
wavelength
comparison by high resolution interferometry.
(USA) 12. GASEOUS
ELECTRONICS I2
1900. ac photoresponse of a large-area junction. (USA)
imaging CdS/CdTe
hetero-
Experimental data are presented for the photosensor-substrate structure presently used with the ac liquid-crystal projection light valve. This structure consists of a thin film (sputter deposited) of n-type CdS on which is evaporated a thin film of p-type CdTe. In an earlier publication, a model was presented which describes the photosensitivity of this structure in terms of the depletion-width photocapacity of the charge-storage diode formed by these two coatings. The experimental data presented here correlate well with this model. Among the data presented are data on light-valve display, photosensor gray scale, and response time. The response-time data are of particular interest because they show that the projection-light-valve photosensor is capable of operation at near-TV rates. The agreement of the experimental data with model and extrapolation from the model imply that large improvements in sensitivity and response time are still quite possible.
High resolution interferometry has been used to determine the wavelength ratio between two molecularly stabilized He-Ne lasers. one locked to a methane absorption at 3.39 pm and the other locked to the k peak of ‘ZslZ at 633 nm. An optical beat frequency technique gave fractional orders while a microwave sideband method yielded the integer parts. Conventional (third derivative) peak seeking servoes stabilized both laser and cavity lengths. Reproducibility of the electronic control system and optics was a few parts in IO”, while systematic errors associated with curvature of the cavity mirrors limited the accuracy of the wavelength ratio measurement to 2 parts in IO“‘. The measured wavelength ratio of the methane stabilized He-Ne laser at 3.39 pm (P(7) line, Y~ band) to the lz91r (k peak) stabilized He-Ne laser at 633 nm was 5.359 049 260 6 (0.000 2 ppm). This ratio agrees with that calculated from the (lower accuracy) results of earlier wavelength measurements made relative to the 86Kr standard. Its higher accuracy thus permits a provisional extension of the frequency scale based on the cesium oscillator into the visible spectrum. H P Layer et al, Appl Opr, 15 (3). 1976, 734-743.
L M Fraas et al, J Appl Phys, 47 (2), 1976,5&l-590.
21. PUMPS
12 1901. Ultraviolet photoemission study of cesium oxide films on GaAs. (USN
1906. A new adsorption adsorbent. (USSR)
Ultraviolet photoemission energy distribution curves (EDC’s) have been measured from a GaAs (110) surface covered with Cs oxide layers of varying thickness. There is no evidence of emission from Cs oxide in the EDC’s from GaAs with a surface treatment that produces optimum yield, but structure characteristic of the GaAs is present in the EDC’s. However. EDC’s characteristic of bulk Cs oxide were measured from GaAs with a thick (at least several molecular layers) Cs oxide surface layer, but no structure characteristic of the GaAs was present in the EDC’s. Compared to the GaAs with the optimum surface treatment, this thick Cs oxide film produced yield spectra having a higher photoemission threshold and a lower yield throughout the photon energy range studied (I .4< /rv< I I .6 eV). These measurements indicate that the Cs oxide layer required for activation of GaAs to negative electron affinity is so thin that the Cs oxide layer does not have bulk properties which can be detected by photoemission. Measurements similar to those reported here on narrower-band-gap III-V alloys should determine if the thickness of the Cs oxide layer required for activation increases with decreasing band gap or is independent of band gap. P E Gregory and W E Spicer, J ApplPhys, 47 (2), 1976,510-517.
1902. Radial protiles of upper-laser-level Arll laser. (USA)
12 emission in an oscillating
Radial profiles of the emission from upper-laser-level ions have been investigated in an oscillating ArII laser and a significant dip in the tube center is observed. (Japan)
T Ihjima et al, J Appl Phys, 47 (I), 1976.383-384. 354
AND
PUMP
FLUIDS
vacuum pump with moving regenerating
Assuming that the diffusion coefficient is constant, the pumping speed of a vacuum adsorption pump with circulating sorbent is calculated and the distribution of the concentration of adsorbed gas in the adsorbent is determined. A model of the operation of such a pump and its design are presented. The calculated dependence of pumping speed on the gas pressure is compared with the experimental one obtained by using aluminosilicate catalyst as an adsorbent. The total amount of adsorbent was 100 g, 30 g was in the adsorption zone. The period of adsorbent transport was 15.5 hours. The ratio of the pressures in the desorption and adsorption zones was 100. The lower value of the experimentally determined pumping speed in comparison with the calculated one is explained by the method of operation, at which the adsorbent temperature in the adsorption chamber does not reach the equilibrium value.
L N Roxanov and L A Kuzinits, Probl of Atomic Science and Technol, Ser P~JJJSand Technol of H~IJ Vacuum, Coil, No I. Kharkov 1973, 33-39 (in Russian). 1.
1907. Vacuum magnetic-discharge
pumps with lower weight. (US&
It is shown that the placing of the magnetic system into the vacuum envelope of magnetic-discharge pumps results in decreasing of their weight coefficient from 0.5 to 0.2 kg 1-i sec. Anisotropic magnets based on barium hexaferrite and characterized by absence of additional demagnetization after repeated heating and cooling, fast degassing in vacuum, high coercive force and low price, have been used. Two types of magnetic system placed in vacuum are presented. For magnetic-discharge pump with high pumping speed above