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LiIn thin-film overlayers
Classified abstracts 5464-5473 Scunthorpe. The availability of a continuous, accurate off-gas analysis has proved of great benefit in terms of operation and control of the ironmaking process and examples are given of the approach taken. A Smith and M J Pettifor, Vacuum, 32 (3), 1982, 175481. 22 5464. Tbe we of mass spechomehy as a process tcchiqoe:an mlu~~tio~~
GW The possibility of using mass-spectrometry as an on-line quantitative analytical tool has been evaluated and shown to have a number of advantages when compared with existing instrumentation. Limitations of the technique and possible ways of minimizing them are discussed and current and possible future applications of the technique are outlined. J H Scrivens, Vacuum, 32 (3), 1982, 169-174. 22 5465. MIIpmeessor eontruIIed quatIn+ mass ma. (GB) The use of a microprocessor in conjunction with the IQ-200 quadrupole mass spectrometer simplifies the operation of the instrument considerably. The various modes of operation are described, including the operational advantages they olTer.The IQ-200 plus microprocessor is a gas analysing instrument which lends itself for use in industrial pioduction line processes, apart from its usefulness in R 8c D. (West Germany) S Buraydi, Vacuum, 32 (3), 1982, 163-168. 22 5466. A ww widexange B-A gauge from uhv to 10-l torr. (USA) In a conventional B-A gauge, the ion collector current shows a strong nonlinearity with increasing pressure above about lo-’ torr. This is considered to be due to the ion current to the filament becoming comparable to the electron emission from the filament. In this new gauge, an auxiliary electrode whose potential is kept lower than that of filament, is placed near the filament to eliminate such an undesirable ion current. By this modification, the linear region is extended up to 10-I torr N, without sa’crificing the sensitivity. Through the optimization study of electrode design parameters such as structure and potential, a gauge with a semicylindrical electrode kept at ground potential gives the best result. This new B-A gauge can cover the pressure range from lo-” to 2 x 10-l torr with linear ion current-pressure characteristics. (Japan) N Ohsaka, J Vuc Sci Tech&, 20 (4), 1982, 1153-1155. 22 5467. CaIIbration of aecoodary standard ioniption gauges. (USA) A McLeod gauge, designed, built and maintained by us, serves as the primary vacuum standard of Japan. We measure the sensitivities for nitrogen of the secondary standard ionization gauges (VS-1) with an accuracy of f3% with the McLcod gauge in the pressure range from 0.01 to 0.3 Pa. The VS-1 gauge is a triode type that shows constant sensitivity from 1 x 10m4to 0.3 Pa. 258 VS-1 gauges were calibrated since 1964. The average value of the sensitivities is 0.137 Pa-‘. About 85% of the gauges have sensitivities with less than f 10% deviation from the average. The main reason for the spread of sensitivities was the electrode displacement. We discuss the technical problems connected with the use of the VS-1 gauge as a transfer gauge for international comparison of vacuum standards. (Japan) M HIta et al, J Voc Sci Tech&, 20 (4), 1982, 1159-1161. 23. PLUMBING, VACUUM VALVES, BAFFLES AND TRAPS 23 5468. Sealing eoneept of dpstic metal gasket ‘HeIIcoiIex’.(GB) ‘Helicoflex’ is a new type of flexible and elastic metal O-ring. In this paper relations between sealing performance and the condition of the sealing surfaces are investigated for the Helicoflex gasket. Two kinds of sealing mechanism were found according to the surface conditions of the flange. In particular, when the surface of flange is superfinished, the soft metal sheet of the Helicoflex in contact with flange surface flows in the gap between elastic core and flange surface as the flanges are tightened. The surface of the gasket in contact with flange takes up the same superfinish by flowing. This is a new concept of sealing by elastic metal gasket. I Sakai et al, Vacuum, 32 (I), 1982, 33-37. 24. LEAK DETECTORS AND LEAK DETECTION 24 5469. The leak testing programme of the doublet III project. (USA) Vacuum integrity of large fusion tokamaks has become increasingly important as the complexity and requirements for cleanliness have increased. Doublet III is a large noncircular tokamak (R= 1.43 m,
V=27 m’) designed for a base pressure of 2 x lo-” torr and a leak rate of 5 x 10e6 torr 1 s-‘. Initial leak testing of the vacuum chamber used conventional techniques. After final asssembly, leak testing became more difficult as diagnostic systems, coil systems and heating blankets enveloped the vacuum vessel. Methods were developed to locate and quantify vacuum leaks in this difficult environment. A residual gas analyser was used for temporal response to gases flowed at various points outside the vessel. Leaks occurring in the primary vessel wall were measured by pumping on gas cooling channels adjacent to the primary vacuum wall. Air in these channels was also displaced by other gases at a constant rate to give location of leaks to within 50 cm. Vacuum leaks occurred during machine operations due to applied stresses, plasmamaterial interactions and diagnostic equipment failures. Machine vents to fix these leaks involve a sign&cant loss of time, particularly in returning to clean wall conditions. Methods other than venting the vessel have been used, such as helium ‘patches’, if these leaks are sufficiently small. G L Jackson. J Vat Sci Techd. . 20 14). . 1982, 1182-1187. 24 5470. He Ieak detection in t!w peaewe of deoterium backgroood in tokamak vacmun systems. (USA) Helium leak detection systems for magnetic fusion devices prrscnt several unique design problems because of the large dynamic range required and the high partial pressures of D, encountered. We describe the design and operation of a He leak detector system for the PDX tokamak. The system consists of a differentially-pumped, low resolution, He maas spectrometer which is interfaced to the foreline of one of the torus turbomolecular pump lines. The He detector has a minimum throughput sensitivity of lo-” torr I s-l, and the torus-integrated system has been designed for detection of torus leaks over the ranae lo-’ to 10 torr 1 s-l. Minimum leak-rates on the 38 m3 PDX vessel which have been quantified using this system are ~3>10-* torr 1 s-l. When PDX is operated with D, plasmas it is n ecessary to reduce the partial pressure of D, by a factor of 100 within the mass spectrometer to maintain this sensitivity in the presence of the torus D, outgassing. We have designed and incorporated a D2 filter which employs a Zr-Al getter assembly to a&t the required D, pressure reduction. W R BIancIurd, J Voc Sci Techd, 20 (4). 1982, 1162-l 165.
III. Vacuum
applications
30. EVAPORATION AND DEPOSITION
IN VACUO
30 5471. A evaporatioo4eld formula including the repulsive ioo-surface ioteractioa (GB) In field-ion emission an evaporation field may be defined by a zeroactivation-energy (zero-Q) criterion. Existing formulae used to roughly predict evaporation field do not take into account the repulsive ionsurface interaction. A new formula, including this interdtion, has been developed. Slightly higher evaporation fields are predicted. The increase should not exceed 25% in most cases, and may often be substantially less than this. Richard G Forbes, J Phys D: Appl Phys, 15 (7), 1982, L75-L77. 30 5472 Electrocbmism of WOJLilFJLiIn thio-f&n overIayers.(USA) A thin, amorphous LiAlF, film, with lithium ion conductivity of 1 x 10m4s m-l at 25”C, has been prepared by vacuum evaporation. Utilizing this thin film as a solid electrolyte, an ITO/WO,/LiAlF,/LiIn overlayer has hecn constructed (ITO: indium-tin-oxide). For it, the electrochromism of WO, due to lithium ion injection was observed. (Japan) Tetsu Oi et al, J Appl Phys, 53 (3), 1982, 1823-1824. 30 5473. McchanIsm for the interoctioo of surface waves with NO-A nickel tihns. (USA) Measurements of the surface wave attenuation of surface wave delay lines coated with nickel films in a magnetic field parallel to the film plane in the frequency range 500-665 MHz exhibit attenuation peaks which depend strongly on film thickness, temperature and magnetic field. The e&t is 347
GW The possibility of using mass-spectrometry as an on-line quantitative analytical tool has been evaluated and shown to have a number of advantages when compared with existing instrumentation. Limitations of the technique and possible ways of minimizing them are discussed and current and possible future applications of the technique are outlined. J H Scrivens, Vacuum, 32 (3), 1982, 169-174. 22 5465. MIIpmeessor eontruIIed quatIn+ mass ma. (GB) The use of a microprocessor in conjunction with the IQ-200 quadrupole mass spectrometer simplifies the operation of the instrument considerably. The various modes of operation are described, including the operational advantages they olTer.The IQ-200 plus microprocessor is a gas analysing instrument which lends itself for use in industrial pioduction line processes, apart from its usefulness in R 8c D. (West Germany) S Buraydi, Vacuum, 32 (3), 1982, 163-168. 22 5466. A ww widexange B-A gauge from uhv to 10-l torr. (USA) In a conventional B-A gauge, the ion collector current shows a strong nonlinearity with increasing pressure above about lo-’ torr. This is considered to be due to the ion current to the filament becoming comparable to the electron emission from the filament. In this new gauge, an auxiliary electrode whose potential is kept lower than that of filament, is placed near the filament to eliminate such an undesirable ion current. By this modification, the linear region is extended up to 10-I torr N, without sa’crificing the sensitivity. Through the optimization study of electrode design parameters such as structure and potential, a gauge with a semicylindrical electrode kept at ground potential gives the best result. This new B-A gauge can cover the pressure range from lo-” to 2 x 10-l torr with linear ion current-pressure characteristics. (Japan) N Ohsaka, J Vuc Sci Tech&, 20 (4), 1982, 1153-1155. 22 5467. CaIIbration of aecoodary standard ioniption gauges. (USA) A McLeod gauge, designed, built and maintained by us, serves as the primary vacuum standard of Japan. We measure the sensitivities for nitrogen of the secondary standard ionization gauges (VS-1) with an accuracy of f3% with the McLcod gauge in the pressure range from 0.01 to 0.3 Pa. The VS-1 gauge is a triode type that shows constant sensitivity from 1 x 10m4to 0.3 Pa. 258 VS-1 gauges were calibrated since 1964. The average value of the sensitivities is 0.137 Pa-‘. About 85% of the gauges have sensitivities with less than f 10% deviation from the average. The main reason for the spread of sensitivities was the electrode displacement. We discuss the technical problems connected with the use of the VS-1 gauge as a transfer gauge for international comparison of vacuum standards. (Japan) M HIta et al, J Voc Sci Tech&, 20 (4), 1982, 1159-1161. 23. PLUMBING, VACUUM VALVES, BAFFLES AND TRAPS 23 5468. Sealing eoneept of dpstic metal gasket ‘HeIIcoiIex’.(GB) ‘Helicoflex’ is a new type of flexible and elastic metal O-ring. In this paper relations between sealing performance and the condition of the sealing surfaces are investigated for the Helicoflex gasket. Two kinds of sealing mechanism were found according to the surface conditions of the flange. In particular, when the surface of flange is superfinished, the soft metal sheet of the Helicoflex in contact with flange surface flows in the gap between elastic core and flange surface as the flanges are tightened. The surface of the gasket in contact with flange takes up the same superfinish by flowing. This is a new concept of sealing by elastic metal gasket. I Sakai et al, Vacuum, 32 (I), 1982, 33-37. 24. LEAK DETECTORS AND LEAK DETECTION 24 5469. The leak testing programme of the doublet III project. (USA) Vacuum integrity of large fusion tokamaks has become increasingly important as the complexity and requirements for cleanliness have increased. Doublet III is a large noncircular tokamak (R= 1.43 m,
V=27 m’) designed for a base pressure of 2 x lo-” torr and a leak rate of 5 x 10e6 torr 1 s-‘. Initial leak testing of the vacuum chamber used conventional techniques. After final asssembly, leak testing became more difficult as diagnostic systems, coil systems and heating blankets enveloped the vacuum vessel. Methods were developed to locate and quantify vacuum leaks in this difficult environment. A residual gas analyser was used for temporal response to gases flowed at various points outside the vessel. Leaks occurring in the primary vessel wall were measured by pumping on gas cooling channels adjacent to the primary vacuum wall. Air in these channels was also displaced by other gases at a constant rate to give location of leaks to within 50 cm. Vacuum leaks occurred during machine operations due to applied stresses, plasmamaterial interactions and diagnostic equipment failures. Machine vents to fix these leaks involve a sign&cant loss of time, particularly in returning to clean wall conditions. Methods other than venting the vessel have been used, such as helium ‘patches’, if these leaks are sufficiently small. G L Jackson. J Vat Sci Techd. . 20 14). . 1982, 1182-1187. 24 5470. He Ieak detection in t!w peaewe of deoterium backgroood in tokamak vacmun systems. (USA) Helium leak detection systems for magnetic fusion devices prrscnt several unique design problems because of the large dynamic range required and the high partial pressures of D, encountered. We describe the design and operation of a He leak detector system for the PDX tokamak. The system consists of a differentially-pumped, low resolution, He maas spectrometer which is interfaced to the foreline of one of the torus turbomolecular pump lines. The He detector has a minimum throughput sensitivity of lo-” torr I s-l, and the torus-integrated system has been designed for detection of torus leaks over the ranae lo-’ to 10 torr 1 s-l. Minimum leak-rates on the 38 m3 PDX vessel which have been quantified using this system are ~3>10-* torr 1 s-l. When PDX is operated with D, plasmas it is n ecessary to reduce the partial pressure of D, by a factor of 100 within the mass spectrometer to maintain this sensitivity in the presence of the torus D, outgassing. We have designed and incorporated a D2 filter which employs a Zr-Al getter assembly to a&t the required D, pressure reduction. W R BIancIurd, J Voc Sci Techd, 20 (4). 1982, 1162-l 165.
III. Vacuum
applications
30. EVAPORATION AND DEPOSITION
IN VACUO
30 5471. A evaporatioo4eld formula including the repulsive ioo-surface ioteractioa (GB) In field-ion emission an evaporation field may be defined by a zeroactivation-energy (zero-Q) criterion. Existing formulae used to roughly predict evaporation field do not take into account the repulsive ionsurface interaction. A new formula, including this interdtion, has been developed. Slightly higher evaporation fields are predicted. The increase should not exceed 25% in most cases, and may often be substantially less than this. Richard G Forbes, J Phys D: Appl Phys, 15 (7), 1982, L75-L77. 30 5472 Electrocbmism of WOJLilFJLiIn thio-f&n overIayers.(USA) A thin, amorphous LiAlF, film, with lithium ion conductivity of 1 x 10m4s m-l at 25”C, has been prepared by vacuum evaporation. Utilizing this thin film as a solid electrolyte, an ITO/WO,/LiAlF,/LiIn overlayer has hecn constructed (ITO: indium-tin-oxide). For it, the electrochromism of WO, due to lithium ion injection was observed. (Japan) Tetsu Oi et al, J Appl Phys, 53 (3), 1982, 1823-1824. 30 5473. McchanIsm for the interoctioo of surface waves with NO-A nickel tihns. (USA) Measurements of the surface wave attenuation of surface wave delay lines coated with nickel films in a magnetic field parallel to the film plane in the frequency range 500-665 MHz exhibit attenuation peaks which depend strongly on film thickness, temperature and magnetic field. The e&t is 347