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6085. Vacuum systems for vacuum microbalances
Vacuum/volume 36/number Printed in Great Britain
Classified
0042-207X/86 $3.00+ .OO Pergamon Journals Ltd
IO/pages 723 to 742/l 986
abstracts
Compiled by H Kheyrandish,
6082-6252
University of Salford
Announcement The classification of abstracts in this feature has been revised. The new classification is as follows.
I. VACUUM SCIENCE AND TECHNOLOGY 10. Vacuum pumps and pumping systems 11. Gauges and measurement of pressure 12. Gaseous interactions with solids 13. Materials and techniques in vacuum II. THIN FILM TECHNOLOGY 20. Evaporation 21. Sputtering 22. Thin film adhesion 23. Ion and plasma assisted film growth III. PARTICLE BEAM TECHNOLOGY AND PROCESSING MATERIALS 30. Particle beams and sources 31. Ion implantation of semiconductors 32. Ion implantation of metals 33. Molecular beam epitaxy 34. Ion beam mixing, interfaces and solid phase reactions 35. Ion and plasma etching
OF
utilizing 460-m long helium gas lines
IV. PLASMA TECHNOLOGY 40. Gaseous discharges and plasma devices 41. Optical electronics and lasers 42. Plasma diagnostics V. ANALYSIS OF MATERIALS AND SURFACES 50. Rutherford backscattering and nuclear reactions 51. Secondary ion mass spectroscopy 52. Ion and electron scattering 53. Auger spectroscopy 54. Electron microscopy 55. X-ray and photoelectron spectroscopy
I. Vacuum science and technology 10. VACUUM PUMPS AND PUMPING
accumulator ring to store antiprotons for high energy physics proteon-antiproton collisions in the Tevatron accelerator. The accumulator ring, approximately 474 m in circumference, consists of many quadrupole and dipole magnets connected with stainless steel vacuum chambers for beam circulation. The vacuum pressure required is in the low 10-i’ torr range. To reach this pressure, the vacuum chambers are baked at 300°C each time they have been opened to atmospheric pressure. The critical problem is to bake the chambers in the magnets at high temperature without overheating the laminated magnets. Some of the magnets are 5 m long with very restrictive space for the heaters and insulation. An average space of only 7.5 mm around the chambers is available. In this space a heating system has been designed and tested to heat the chamber to 300°C and allow a maximum temperature of 65°C next to the magnet components. This was accomplished by using a heating blanket completely covered with a water cooled copper heat sink jacket to protect the magnet from the high temperatures. The design of a final selected heating blanket is discussed. A prototype test results are given with comparison of calculated and measured temperature distribution. J A Satti and G N Lee, J Vat Sci Technol, A3, 1985, 1695-1698. 10 6084. An underground remotely controlled cryopump vacuum system
SYSTEMS
10 6082. All aluminum alloy, IWO-mm-inner diameter gate valve using dual flat-face seals together with differential pumping
Large metal gate valves are required in the neutral beam injector (NBI) of the R-Tokamak [Ref 1: The second phase design of R-Tokamak (low radioactivity design), Institute of Plasma Physics, Nagoya University, Nagoya, 464, Japan, Dee 1983.1 at the Institute of Plasma Physics, Nagoya University. The R-Tokamak is designed using aluminum alloys because of the low residual radioactivity. Therefore, the gate valve for the NBI should also be made of aluminum alloys. By relying on differential pumping between dual flat-face seals [Ref 2: H. Ishimaru, J Vat Sci Technol, AZ, 1170 (1984).], we developed a large gate valve which has no gasket or knife edge. H Ishimaru et al, J Vat Sci Technol, A3, 1985, 1703-1706. IU
6083. Fermilab accumulator magnets vacuum chamber heating system The Fermi National Accelerator Laboratory (Fermilab) is building an
A 1600 1 vacuum chamber buried 300 m underground required a continuous operational vacuum of < 1 x 10m6 torr. Due to physics criteria, high gas load (2 x 10m2 torr 1 s-i), space limitations, harsh operating environment and reliability requirements, a cryopump vacuum system was designed to meet all design and operational requirements. The vacuum system consisted of downhole and uphole subsystems linked by 460 m long pressurized copper helium gas lines and control cables. The uphole subsystem consisted of the helium compressors, automatic control, and monitoring system. The downhole system consisted of the vacuum pumps and all related supported hardware necessary for long unattended remote operation. The design, installation, and operational requirements are reviewed and summarized for this initial and unusual application of remotely operated cryopumps. V P Karpenko et al, J Vat Sci Technol, A3, 1985, 1690-1694. 10 6085. Vacuum systems for vacuum microbalauces Five types of vacuum balances are in use today: electromagnetically compensated beam balances; magnetic suspension balances; spring balances; quartz resonators and strain gauges. The last two types are usually arranged in bell jar apparatus. In the case ofsuspension balances, a small vessel includes the permanent magnet and the sample. Beam and spring balances are enclosed in special cases and, because of the requirements of thermostatting, the sample is arranged within a tube of up to 1 m in length and 14 cm in diameter. When designing gravimetric apparatus, it is necessary to take into account the geometry of the balance and its sensitivity to vibration and shocks, as well as requirements for thermal, chemical and other treatments of the sample and additional instrumentation. Gas evolution by the sample and disturbances by thermally or electrically induced gas flow has to be considered. To exclude vibrations, the balance has to be placed on a heavy stand, e.g. a hollow vertical support on T-shaped steel beams insulated from the ground. The primary pump is arranged separately. A turbomolecular pump can be suspended on a short, wide, stainless steel bellows. Slowly operating valves must be used, e.g. disc valves which are operated by a dc magnet. 723
Classified
0042-207X/86 $3.00+ .OO Pergamon Journals Ltd
IO/pages 723 to 742/l 986
abstracts
Compiled by H Kheyrandish,
6082-6252
University of Salford
Announcement The classification of abstracts in this feature has been revised. The new classification is as follows.
I. VACUUM SCIENCE AND TECHNOLOGY 10. Vacuum pumps and pumping systems 11. Gauges and measurement of pressure 12. Gaseous interactions with solids 13. Materials and techniques in vacuum II. THIN FILM TECHNOLOGY 20. Evaporation 21. Sputtering 22. Thin film adhesion 23. Ion and plasma assisted film growth III. PARTICLE BEAM TECHNOLOGY AND PROCESSING MATERIALS 30. Particle beams and sources 31. Ion implantation of semiconductors 32. Ion implantation of metals 33. Molecular beam epitaxy 34. Ion beam mixing, interfaces and solid phase reactions 35. Ion and plasma etching
OF
utilizing 460-m long helium gas lines
IV. PLASMA TECHNOLOGY 40. Gaseous discharges and plasma devices 41. Optical electronics and lasers 42. Plasma diagnostics V. ANALYSIS OF MATERIALS AND SURFACES 50. Rutherford backscattering and nuclear reactions 51. Secondary ion mass spectroscopy 52. Ion and electron scattering 53. Auger spectroscopy 54. Electron microscopy 55. X-ray and photoelectron spectroscopy
I. Vacuum science and technology 10. VACUUM PUMPS AND PUMPING
accumulator ring to store antiprotons for high energy physics proteon-antiproton collisions in the Tevatron accelerator. The accumulator ring, approximately 474 m in circumference, consists of many quadrupole and dipole magnets connected with stainless steel vacuum chambers for beam circulation. The vacuum pressure required is in the low 10-i’ torr range. To reach this pressure, the vacuum chambers are baked at 300°C each time they have been opened to atmospheric pressure. The critical problem is to bake the chambers in the magnets at high temperature without overheating the laminated magnets. Some of the magnets are 5 m long with very restrictive space for the heaters and insulation. An average space of only 7.5 mm around the chambers is available. In this space a heating system has been designed and tested to heat the chamber to 300°C and allow a maximum temperature of 65°C next to the magnet components. This was accomplished by using a heating blanket completely covered with a water cooled copper heat sink jacket to protect the magnet from the high temperatures. The design of a final selected heating blanket is discussed. A prototype test results are given with comparison of calculated and measured temperature distribution. J A Satti and G N Lee, J Vat Sci Technol, A3, 1985, 1695-1698. 10 6084. An underground remotely controlled cryopump vacuum system
SYSTEMS
10 6082. All aluminum alloy, IWO-mm-inner diameter gate valve using dual flat-face seals together with differential pumping
Large metal gate valves are required in the neutral beam injector (NBI) of the R-Tokamak [Ref 1: The second phase design of R-Tokamak (low radioactivity design), Institute of Plasma Physics, Nagoya University, Nagoya, 464, Japan, Dee 1983.1 at the Institute of Plasma Physics, Nagoya University. The R-Tokamak is designed using aluminum alloys because of the low residual radioactivity. Therefore, the gate valve for the NBI should also be made of aluminum alloys. By relying on differential pumping between dual flat-face seals [Ref 2: H. Ishimaru, J Vat Sci Technol, AZ, 1170 (1984).], we developed a large gate valve which has no gasket or knife edge. H Ishimaru et al, J Vat Sci Technol, A3, 1985, 1703-1706. IU
6083. Fermilab accumulator magnets vacuum chamber heating system The Fermi National Accelerator Laboratory (Fermilab) is building an
A 1600 1 vacuum chamber buried 300 m underground required a continuous operational vacuum of < 1 x 10m6 torr. Due to physics criteria, high gas load (2 x 10m2 torr 1 s-i), space limitations, harsh operating environment and reliability requirements, a cryopump vacuum system was designed to meet all design and operational requirements. The vacuum system consisted of downhole and uphole subsystems linked by 460 m long pressurized copper helium gas lines and control cables. The uphole subsystem consisted of the helium compressors, automatic control, and monitoring system. The downhole system consisted of the vacuum pumps and all related supported hardware necessary for long unattended remote operation. The design, installation, and operational requirements are reviewed and summarized for this initial and unusual application of remotely operated cryopumps. V P Karpenko et al, J Vat Sci Technol, A3, 1985, 1690-1694. 10 6085. Vacuum systems for vacuum microbalauces Five types of vacuum balances are in use today: electromagnetically compensated beam balances; magnetic suspension balances; spring balances; quartz resonators and strain gauges. The last two types are usually arranged in bell jar apparatus. In the case ofsuspension balances, a small vessel includes the permanent magnet and the sample. Beam and spring balances are enclosed in special cases and, because of the requirements of thermostatting, the sample is arranged within a tube of up to 1 m in length and 14 cm in diameter. When designing gravimetric apparatus, it is necessary to take into account the geometry of the balance and its sensitivity to vibration and shocks, as well as requirements for thermal, chemical and other treatments of the sample and additional instrumentation. Gas evolution by the sample and disturbances by thermally or electrically induced gas flow has to be considered. To exclude vibrations, the balance has to be placed on a heavy stand, e.g. a hollow vertical support on T-shaped steel beams insulated from the ground. The primary pump is arranged separately. A turbomolecular pump can be suspended on a short, wide, stainless steel bellows. Slowly operating valves must be used, e.g. disc valves which are operated by a dc magnet. 723