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A scattering chamber for charged particle work
Classified abstracts 529-541 18 529. Energy release in a high-current vacuum discharge. (USSR) The high efficiency of the conversion of energy stored in a capacitor into the energy of erosion products of the electrodes in a high current discharge in a vacuum is demonstrated experimentally.
B A Osadin, Zh Tekh Fiz, 35 (7), 1965, 1230-1235, (in Russian).
II. Vacuum apparatus and auxiliaries 20. Pumping systems 20 : 10 Central vacuum system for vacunm-treating components of special electrical vacuum apparatus. See abstract number 506. 20:11 Ultrahigh vacuum systems. See abstract number 508. 20 : 23 A scattering chamber for charged particle work. See abstract number 538. 20 : 33 Vacuum systems for X-ray structural investigations. See abstract number 639. 20 : 33 Questions relating to the construction and operation of hydrogenbeam quantum generators. See abstract number 651. 20 : 37 : 33 Apparatus for the non-crucible zone melting of refractory metals. See abstract number 673. 20:21 530. Hcatable condensation pumps. (USSR) Condensation pumps operating at liquid-hydrogen or helium temperatures are discussed. These are suitable for attaining high vacuum (10 -1° tort) in large metal enclosures in a relatively short time. Some experiments with such pumps are described and possible improvements considered. The possibility of eliminating the nitrogen screen and improving the preconditioning of the system with the help of oil-diffusion pumps is discussed. This may improve the pumping rate by a factor of 1.5 without increasing the consumption of liquid hydrogen. A level of 5 × 10 -1° torr can thus be achieved in some 5 hours pumping. Higher and better vacuum can be attained by using helium. E S Borovik et al, Academy of Sciences, UkrSSR, Section 111, 1965,
105, (in Russian). 2O 531. A large ultrahigh-vacuum environmental chamber with liquid helium cooled walls. (USA) The construction and operation of an ultrahigh-vacuum environmental chamber with cryogenic walls at liquid helium temperature are described. This chamber attains low pressures similar to those in space, by a combination of differential pumping and cryogenic pumping. Schematics of the vacuum facility and the refrigerator are shown, and a detailed discussion of each of the components of the vacuum system is presented. C D Elderkin and J M Bradford, RCA Service Co Inc, Camden, N J,
1965, 20 pages. 20 : 30 532. Apparatus for obtaining ferromagnetic films by evaporation in a high vacuum. (USSR) A vacuum system incorporating multi-stage pumping with a double vacuum chamber and heat-resistant seals is described. This gives a vacuum of 10 -~ torr. The first stage is a low-power diffusion pump acting through long copper tubes; a second diffusion pump reduces the pressure to 10 -5 torr in the guard chambers, and like the first, uses VM-1 oil and operates without a nitrogen trap. The final low pressure can only be reached after eliminating leaks; the double vacuum chamber ensures this. Five references. N Z Miryasov et al, Pribory i Tekh Eksper, 5, 1965, 194-197. 20 : 37 533. Vacuum furnace for loads up to 2000 lbs. (USA) Horizontal-loading vacuum furnace can operate up to 3,800°F at vacuum up t o 10 -e tort. Unit will accommodate work loads up to 2000 lb, and, because of high speed, inert-gas quenching, short heating/cooling cycles are possible even with maximum loads. Anon, ABAR Corp, 2424 Wyandotte Road, Willow Grove, Pa, USA.
20 : 28 : 30 534. Vacuum evaporator with an improved electron bombardment heating unit. (Japan) A vacuum evaporator is described, which was constructed in order to prevent charge accumulation on the surfaces of the evaporated. thin films. In this construction the cathode and the metal bell jar are grounded and the anode and the source material are kept at a high potential. The anode is fitted with a metal cylinder through which the accelerated electrons pass to impinge on the source material. The electrostatic field between the cylinder and the bell jar deflects the reflected electrons so as to prevent them from striking the substrate. (Authors) H Tamura and H Kimura, JApplPhys Japan, 4,1965, 622-623. 20 535. Ultrahigh-vacuum system attains 10 -11 torr range. (USA) Environmental test chamber of 18 in. diameter by 42 in. attains basic pressure of 2.7 × 10 -11 tort in 24 hours. The chamber is equipped with cryopanel and bake-out jacket for thermal cycling from --325 to q-720°F. Pumping units of system include six in high speed and two in diffusion pumping in series, mechanical backing pump, and titanium sublimation pump. Anon, Tluvac Inc, W Hanover, Mass, USA. 2O 536. Vacuum bell jar system. (USA) The Vacutron Mark 1 has been designed for thin film deposition, vacuum leak testing and environmental testing. It is capable of rapid, repetitive pump-down into the very high vacuum regions using Pyrex bell jars. The system will reach 3 × 10 -7 torr within 15 rain. with an ultimate pressure capacity of 3 × 10 -s torr. The Mark ! is supplied with a Bayard-Alpert ionization and 2-station thermocouple that reads pressures from 1000 to 2 × 10 -1° tort. R H Stansfield, Lindberg/Hevi duty Division, 304 Hart St, Water-
town, Wisconsin. 20 : 23 537. An improved strip sealed continuous rotating scattering chamber.
(Netherlands) An improved design of an evacuated aluminium chamber of 12-in. diameter with two ports in horizontal plane is described. The angle between these ports can be changed continuously through an angular range of 180 ° without disturbing the high vacuum maintained in the chamber. The body of the chamber is rotated, the entrance port being attached to the 1-in. wide stationary stainless-steel sealing strip. This strip covers the slot and is clamped against the gasket by two fastening strips. A Teflon sheet inserted between the strip and the clamp minimizes the friction, so the chamber can be rotated, requiring a torque of 40 ft lb. The optimum conditions for the seal such as: type of gasket, dimensions of the O-ring, compression ratio, groove dimensions are discussed. (Author) R A Hawrylak et al, Nuclear lnstrum and Methods, 36, 1965, 237-
240. 20 : 23 538. A scattering chamber for charged particle work. (Netherlands) A scattering chamber is described which offers a great flexibility in the arrangement of counters. Two concentric turntables are mounted at the bottom of the chamber (22 in. diameter, 5 in. high). The vacuum seals and the vacuum pumping system used to attain 1 × 10 -6 torr are described and the operation of the chamber is discussed. (Author) R W Zurmiihle, Nuclear lnstrum and Methods, 36, 1965,
168-172. 20 539. Miniature demountable two-channel electric feedthrough for high vacuum chamber. (USA) P J Harbour, Rev Scilnstrum, 36 (11), Nov 1965, 1657-1658. 20 : 21 540. Technological needs lead to better vacua. (USA) Demands of advancing technology, such as space simulation, metallurgy, thin film deposition, have produced ultra-clean vacua as low as 10 -14 torr using a molecular sieve. Anon, Chem Eng News, 43 (50), 1965, 46-47. 20 : 37 : 41 541. Vacuum furnace. (USA) A new high temperature vacuum furnace " H o t Vac" for small scale production and development processing at temperatures up to 4000 °F is reported. Applications include sintering tantalum capacitors, carbides, nitrides, and borides; heat treating of refractory and
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B A Osadin, Zh Tekh Fiz, 35 (7), 1965, 1230-1235, (in Russian).
II. Vacuum apparatus and auxiliaries 20. Pumping systems 20 : 10 Central vacuum system for vacunm-treating components of special electrical vacuum apparatus. See abstract number 506. 20:11 Ultrahigh vacuum systems. See abstract number 508. 20 : 23 A scattering chamber for charged particle work. See abstract number 538. 20 : 33 Vacuum systems for X-ray structural investigations. See abstract number 639. 20 : 33 Questions relating to the construction and operation of hydrogenbeam quantum generators. See abstract number 651. 20 : 37 : 33 Apparatus for the non-crucible zone melting of refractory metals. See abstract number 673. 20:21 530. Hcatable condensation pumps. (USSR) Condensation pumps operating at liquid-hydrogen or helium temperatures are discussed. These are suitable for attaining high vacuum (10 -1° tort) in large metal enclosures in a relatively short time. Some experiments with such pumps are described and possible improvements considered. The possibility of eliminating the nitrogen screen and improving the preconditioning of the system with the help of oil-diffusion pumps is discussed. This may improve the pumping rate by a factor of 1.5 without increasing the consumption of liquid hydrogen. A level of 5 × 10 -1° torr can thus be achieved in some 5 hours pumping. Higher and better vacuum can be attained by using helium. E S Borovik et al, Academy of Sciences, UkrSSR, Section 111, 1965,
105, (in Russian). 2O 531. A large ultrahigh-vacuum environmental chamber with liquid helium cooled walls. (USA) The construction and operation of an ultrahigh-vacuum environmental chamber with cryogenic walls at liquid helium temperature are described. This chamber attains low pressures similar to those in space, by a combination of differential pumping and cryogenic pumping. Schematics of the vacuum facility and the refrigerator are shown, and a detailed discussion of each of the components of the vacuum system is presented. C D Elderkin and J M Bradford, RCA Service Co Inc, Camden, N J,
1965, 20 pages. 20 : 30 532. Apparatus for obtaining ferromagnetic films by evaporation in a high vacuum. (USSR) A vacuum system incorporating multi-stage pumping with a double vacuum chamber and heat-resistant seals is described. This gives a vacuum of 10 -~ torr. The first stage is a low-power diffusion pump acting through long copper tubes; a second diffusion pump reduces the pressure to 10 -5 torr in the guard chambers, and like the first, uses VM-1 oil and operates without a nitrogen trap. The final low pressure can only be reached after eliminating leaks; the double vacuum chamber ensures this. Five references. N Z Miryasov et al, Pribory i Tekh Eksper, 5, 1965, 194-197. 20 : 37 533. Vacuum furnace for loads up to 2000 lbs. (USA) Horizontal-loading vacuum furnace can operate up to 3,800°F at vacuum up t o 10 -e tort. Unit will accommodate work loads up to 2000 lb, and, because of high speed, inert-gas quenching, short heating/cooling cycles are possible even with maximum loads. Anon, ABAR Corp, 2424 Wyandotte Road, Willow Grove, Pa, USA.
20 : 28 : 30 534. Vacuum evaporator with an improved electron bombardment heating unit. (Japan) A vacuum evaporator is described, which was constructed in order to prevent charge accumulation on the surfaces of the evaporated. thin films. In this construction the cathode and the metal bell jar are grounded and the anode and the source material are kept at a high potential. The anode is fitted with a metal cylinder through which the accelerated electrons pass to impinge on the source material. The electrostatic field between the cylinder and the bell jar deflects the reflected electrons so as to prevent them from striking the substrate. (Authors) H Tamura and H Kimura, JApplPhys Japan, 4,1965, 622-623. 20 535. Ultrahigh-vacuum system attains 10 -11 torr range. (USA) Environmental test chamber of 18 in. diameter by 42 in. attains basic pressure of 2.7 × 10 -11 tort in 24 hours. The chamber is equipped with cryopanel and bake-out jacket for thermal cycling from --325 to q-720°F. Pumping units of system include six in high speed and two in diffusion pumping in series, mechanical backing pump, and titanium sublimation pump. Anon, Tluvac Inc, W Hanover, Mass, USA. 2O 536. Vacuum bell jar system. (USA) The Vacutron Mark 1 has been designed for thin film deposition, vacuum leak testing and environmental testing. It is capable of rapid, repetitive pump-down into the very high vacuum regions using Pyrex bell jars. The system will reach 3 × 10 -7 torr within 15 rain. with an ultimate pressure capacity of 3 × 10 -s torr. The Mark ! is supplied with a Bayard-Alpert ionization and 2-station thermocouple that reads pressures from 1000 to 2 × 10 -1° tort. R H Stansfield, Lindberg/Hevi duty Division, 304 Hart St, Water-
town, Wisconsin. 20 : 23 537. An improved strip sealed continuous rotating scattering chamber.
(Netherlands) An improved design of an evacuated aluminium chamber of 12-in. diameter with two ports in horizontal plane is described. The angle between these ports can be changed continuously through an angular range of 180 ° without disturbing the high vacuum maintained in the chamber. The body of the chamber is rotated, the entrance port being attached to the 1-in. wide stationary stainless-steel sealing strip. This strip covers the slot and is clamped against the gasket by two fastening strips. A Teflon sheet inserted between the strip and the clamp minimizes the friction, so the chamber can be rotated, requiring a torque of 40 ft lb. The optimum conditions for the seal such as: type of gasket, dimensions of the O-ring, compression ratio, groove dimensions are discussed. (Author) R A Hawrylak et al, Nuclear lnstrum and Methods, 36, 1965, 237-
240. 20 : 23 538. A scattering chamber for charged particle work. (Netherlands) A scattering chamber is described which offers a great flexibility in the arrangement of counters. Two concentric turntables are mounted at the bottom of the chamber (22 in. diameter, 5 in. high). The vacuum seals and the vacuum pumping system used to attain 1 × 10 -6 torr are described and the operation of the chamber is discussed. (Author) R W Zurmiihle, Nuclear lnstrum and Methods, 36, 1965,
168-172. 20 539. Miniature demountable two-channel electric feedthrough for high vacuum chamber. (USA) P J Harbour, Rev Scilnstrum, 36 (11), Nov 1965, 1657-1658. 20 : 21 540. Technological needs lead to better vacua. (USA) Demands of advancing technology, such as space simulation, metallurgy, thin film deposition, have produced ultra-clean vacua as low as 10 -14 torr using a molecular sieve. Anon, Chem Eng News, 43 (50), 1965, 46-47. 20 : 37 : 41 541. Vacuum furnace. (USA) A new high temperature vacuum furnace " H o t Vac" for small scale production and development processing at temperatures up to 4000 °F is reported. Applications include sintering tantalum capacitors, carbides, nitrides, and borides; heat treating of refractory and
221