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Semicontinuous vacuum furnace
Classified
abstracts
1368-1380
applications is presented. A logical breakdown of the various types of discharge sources and a list of parameters to be considered are given. As an example an analytical and experimental study of the fully developed Iaminar flow, argon, electric arc discharge is included. P W Schreiber and K R Benedetto, Rep ARL-67-0179; AD-662350; Aug 1967, 39 pages (Sci Tech Aerospace
Reps 6 (6), 890, N68-15645).
19. RADIATION 19: 18 Comparative investigations of arc and high frequency discharges used in neon-helium lasers. See abstract number 1342.
pulse plasma injection, is described. The gauge is insensitive to 450 changes in the magnetic field direction. Its design is based on the hot cathode ionization gauge but instead of the grid a system of slots is used. To avoid noise signals from charged particles the electron current is modulated. This gauge has a sensitivity of about 400 torr-‘, time constant of 0.1 msec, and the range of 5x 1O-5 to 7x 1O-9 torr is linear. The gaugehead is bakeable to 450°C by external heating or by electron bombardment. Using this gauge, the changes of residual neutral gas during the working range of the PR-5 were measured. These changes are caused mostly by desorption from the system walls under the action of plasma. Yu N Kotel’nikov and G P Kutukov, Zh Tekh Fiz, 38 (5), May 1968, 8 18-822 (in Russian).
II.
Vacuum
20. PUMPING
apparatus
22 : 33 1374. Ion-optical system with strong focusing for a mass spectrometer ion source. (USSR)
and auxiliaries
SYSTEMS
20 : 33 1368. Improved vacuum system for electron microscopes. (USA) Various aspects of the inconveniences caused by impurities in electron microscopes are discussed. In an attempt to reduce the contamination problem in the microscope column, a turbomolecular oil-free pump was substituted for the oil diffusion pump. This improved basically the cleanliness of the system. A R Taylor et al, Rev Sci Znstrum, 39 (5), 1968, 780-781. 20 1369. Semicontinuous
: 37
vacuum furnace.
(USA) An in-line vacuum chamber system is presented, in which two chambers used for batch loading and unloading are placed in line with a centrally located transfer chamber, the chambers being isolated from each other by high vacuum sliding valves. Although the system was developed for sintering of tantalum anodes at temperatures of about 2200°C and pressures in the range of 1O-5 torr, it can be also used for annealing, brazing or sintering of other refractory metal-pressed powder parts. T M Miller, Res/ Develop, 19 (5), 1968, 46-47. 20 : 32 1370. Vacuum system of the stellarator Sirius. (USSR) The system volume of 100 litres is pumped by the RVA-I-2 assembly using a Hg diffusion pump with the speed of 600 litres/sec down to 4x 1Om’otorr. The system is bakeable at 450°C and constructed in stainless steel with ceramic and glass parts sealed by copper gaskets. The design of an externally bakeable LN, trap is described as well as a bakeable UHV valve, 200 mm diameter with the stainless steel seat, knife edge and copper disc. After one working cycle the system is baked at 200°C to reach the previous value of vacuum, ie containing only H,O, CO and CO,. The system was designed at FTI AN USSR Kharkov. E D Volkov et al, Zh Tekh Fiz, 38 (6), June 1968,979-985 (in Russian). 20 : 41 1371. Device for investigation of the external friction and wear of materials under extreme conditions. (USSR) A system is described for investigating friction in high-melting point materials in the temperature range of 20 to 2,OOO”Cunder vacuum of 1O-5 torr at loadings up to 40 kg/cm2 and speeds of 0.6 to 5.4 m/min. A Ya Artamonov and Yu G Tkachenko, Zavodsk Lab, 34 (5), 1968, 609-611 (in Russian). 21. PUMPS
AND PUMP
FLUIDS
21 : 18 Power distribution between electrodes in a Penning discharge. See abstract number 1339. 21 :44 1372. Secondary electron emission from diffusion pump oils. (Japan) Secondary electron emission properties of DC-705 oil have been studied. The values found are much smaller than those for other molecular substances. The possible causes are discussed. K Goto and K Ishikawa, Japan J Appl Phys, 7 (3), 1968, 227-23 1. 22. GAUGES
22 : 32 1373. Measurements of neutral gas density in the working range of the PR-5 system. (USSR) The design of the PR-5, a new gauge for plasma magnetic traps with 576
Two types of systems for forming quasiparallel ion beams are theoretically discussed and experimentally verified: systems using homogeneous fields and lens systems. Beams produced by these systems are formed by a quadrupole doublet and beams with horizontal divergence below 1.5” and vertical divergence below 10” are obtained at a cross section of 5 by 0.2 mm. L N Gall’ et al, Zh Tekh Fiz, 38 (6), June 1968, 1043-1051 (in Russian). 1375. Improvement (USSR)
in the sensitivity
of mass spectrometer
22 MKh-1303.
A simple improvement in output stage of the ion current amplifier is described which results in higher sensitivity in the commerciallyavailable mass spectrometer MKh-1303. A A Kravchenko, Zavodsk
Lab, 34 (5), 1968, 622-624
(in Russian).
1376. Simple liquid helium pressure transducer. (USA) A totally immersed capsule type pressure transducer has been developed for the study of critical velocities in liquid helium below the lambda point. The transducer consists of a small, cylindrical capsule made of Monel of approximately 3 cm diam. A 304 stainless steel stretched membrane 25 microns thick forms one face of the capsule, and is gilver soldered to the capsule. The capsule forms a completely closed vacuum tight chamber with essentially zero inside reference pressure under normal low temperature operation. The membrane face of the capsule constitutes one plate of a capacitor; the other plate being stationary. Changes in pressure in the medium outside the capsule tend to bow the membrane hence changing the capacitance. M Chester et al, Rev Sci Znstrum, 39 (5), 1968, 719-722. 23. PLUMBING 1377. High voltage coaxial connector for helium cryostats.
(us;
A coaxial connector (not constant impedance) which avoids breakdown in the helium vapour for rf voltages up to 2.5 kV is described. It is based on a simple modification of a standard hermetic seal BNC connector. The breakdown is prevented by covering the central conductor, which carries the large rf voltage, with a high dielectric strength material. W G Clark, Rev Sci Znstrum, 39 (4), 1968, 601-602. 23 1378. Electrical feedthroughs
for use at low temperatures.
(USA)
A vacuum feedthrough for use at liquid helium temperatures is described. The feedthrough is based on elastic couper sealed __ cylinders _ with Stycast epoxy resins. A C Anderson, Rev Sci Instrum, 1379. High vacuum motion. (USA)
feedthrough
39 (4), 1968, 605-606. for
rotational
and
23 translational
A feedthrough is described which uses a Teflon plug threaded into a precision bore glass shell. The feedthroughs were successfully used for external adjustment of mirrors located within a vacuum chamber maintained in the pressure range 1O-6 to 10es torr. C S Pannenter and M W Schuyler, Rev Sci Instrum, 39 (4), 1968,611. 23 1380. High vacuum motor. (USA) An arrangement is described in which a motor is installed in the vacuum chamber enclosed in a vacuum sealed housing and having a magnetically coupled rotary feedthrough. Provision is made for
abstracts
1368-1380
applications is presented. A logical breakdown of the various types of discharge sources and a list of parameters to be considered are given. As an example an analytical and experimental study of the fully developed Iaminar flow, argon, electric arc discharge is included. P W Schreiber and K R Benedetto, Rep ARL-67-0179; AD-662350; Aug 1967, 39 pages (Sci Tech Aerospace
Reps 6 (6), 890, N68-15645).
19. RADIATION 19: 18 Comparative investigations of arc and high frequency discharges used in neon-helium lasers. See abstract number 1342.
pulse plasma injection, is described. The gauge is insensitive to 450 changes in the magnetic field direction. Its design is based on the hot cathode ionization gauge but instead of the grid a system of slots is used. To avoid noise signals from charged particles the electron current is modulated. This gauge has a sensitivity of about 400 torr-‘, time constant of 0.1 msec, and the range of 5x 1O-5 to 7x 1O-9 torr is linear. The gaugehead is bakeable to 450°C by external heating or by electron bombardment. Using this gauge, the changes of residual neutral gas during the working range of the PR-5 were measured. These changes are caused mostly by desorption from the system walls under the action of plasma. Yu N Kotel’nikov and G P Kutukov, Zh Tekh Fiz, 38 (5), May 1968, 8 18-822 (in Russian).
II.
Vacuum
20. PUMPING
apparatus
22 : 33 1374. Ion-optical system with strong focusing for a mass spectrometer ion source. (USSR)
and auxiliaries
SYSTEMS
20 : 33 1368. Improved vacuum system for electron microscopes. (USA) Various aspects of the inconveniences caused by impurities in electron microscopes are discussed. In an attempt to reduce the contamination problem in the microscope column, a turbomolecular oil-free pump was substituted for the oil diffusion pump. This improved basically the cleanliness of the system. A R Taylor et al, Rev Sci Znstrum, 39 (5), 1968, 780-781. 20 1369. Semicontinuous
: 37
vacuum furnace.
(USA) An in-line vacuum chamber system is presented, in which two chambers used for batch loading and unloading are placed in line with a centrally located transfer chamber, the chambers being isolated from each other by high vacuum sliding valves. Although the system was developed for sintering of tantalum anodes at temperatures of about 2200°C and pressures in the range of 1O-5 torr, it can be also used for annealing, brazing or sintering of other refractory metal-pressed powder parts. T M Miller, Res/ Develop, 19 (5), 1968, 46-47. 20 : 32 1370. Vacuum system of the stellarator Sirius. (USSR) The system volume of 100 litres is pumped by the RVA-I-2 assembly using a Hg diffusion pump with the speed of 600 litres/sec down to 4x 1Om’otorr. The system is bakeable at 450°C and constructed in stainless steel with ceramic and glass parts sealed by copper gaskets. The design of an externally bakeable LN, trap is described as well as a bakeable UHV valve, 200 mm diameter with the stainless steel seat, knife edge and copper disc. After one working cycle the system is baked at 200°C to reach the previous value of vacuum, ie containing only H,O, CO and CO,. The system was designed at FTI AN USSR Kharkov. E D Volkov et al, Zh Tekh Fiz, 38 (6), June 1968,979-985 (in Russian). 20 : 41 1371. Device for investigation of the external friction and wear of materials under extreme conditions. (USSR) A system is described for investigating friction in high-melting point materials in the temperature range of 20 to 2,OOO”Cunder vacuum of 1O-5 torr at loadings up to 40 kg/cm2 and speeds of 0.6 to 5.4 m/min. A Ya Artamonov and Yu G Tkachenko, Zavodsk Lab, 34 (5), 1968, 609-611 (in Russian). 21. PUMPS
AND PUMP
FLUIDS
21 : 18 Power distribution between electrodes in a Penning discharge. See abstract number 1339. 21 :44 1372. Secondary electron emission from diffusion pump oils. (Japan) Secondary electron emission properties of DC-705 oil have been studied. The values found are much smaller than those for other molecular substances. The possible causes are discussed. K Goto and K Ishikawa, Japan J Appl Phys, 7 (3), 1968, 227-23 1. 22. GAUGES
22 : 32 1373. Measurements of neutral gas density in the working range of the PR-5 system. (USSR) The design of the PR-5, a new gauge for plasma magnetic traps with 576
Two types of systems for forming quasiparallel ion beams are theoretically discussed and experimentally verified: systems using homogeneous fields and lens systems. Beams produced by these systems are formed by a quadrupole doublet and beams with horizontal divergence below 1.5” and vertical divergence below 10” are obtained at a cross section of 5 by 0.2 mm. L N Gall’ et al, Zh Tekh Fiz, 38 (6), June 1968, 1043-1051 (in Russian). 1375. Improvement (USSR)
in the sensitivity
of mass spectrometer
22 MKh-1303.
A simple improvement in output stage of the ion current amplifier is described which results in higher sensitivity in the commerciallyavailable mass spectrometer MKh-1303. A A Kravchenko, Zavodsk
Lab, 34 (5), 1968, 622-624
(in Russian).
1376. Simple liquid helium pressure transducer. (USA) A totally immersed capsule type pressure transducer has been developed for the study of critical velocities in liquid helium below the lambda point. The transducer consists of a small, cylindrical capsule made of Monel of approximately 3 cm diam. A 304 stainless steel stretched membrane 25 microns thick forms one face of the capsule, and is gilver soldered to the capsule. The capsule forms a completely closed vacuum tight chamber with essentially zero inside reference pressure under normal low temperature operation. The membrane face of the capsule constitutes one plate of a capacitor; the other plate being stationary. Changes in pressure in the medium outside the capsule tend to bow the membrane hence changing the capacitance. M Chester et al, Rev Sci Znstrum, 39 (5), 1968, 719-722. 23. PLUMBING 1377. High voltage coaxial connector for helium cryostats.
(us;
A coaxial connector (not constant impedance) which avoids breakdown in the helium vapour for rf voltages up to 2.5 kV is described. It is based on a simple modification of a standard hermetic seal BNC connector. The breakdown is prevented by covering the central conductor, which carries the large rf voltage, with a high dielectric strength material. W G Clark, Rev Sci Znstrum, 39 (4), 1968, 601-602. 23 1378. Electrical feedthroughs
for use at low temperatures.
(USA)
A vacuum feedthrough for use at liquid helium temperatures is described. The feedthrough is based on elastic couper sealed __ cylinders _ with Stycast epoxy resins. A C Anderson, Rev Sci Instrum, 1379. High vacuum motion. (USA)
feedthrough
39 (4), 1968, 605-606. for
rotational
and
23 translational
A feedthrough is described which uses a Teflon plug threaded into a precision bore glass shell. The feedthroughs were successfully used for external adjustment of mirrors located within a vacuum chamber maintained in the pressure range 1O-6 to 10es torr. C S Pannenter and M W Schuyler, Rev Sci Instrum, 39 (4), 1968,611. 23 1380. High vacuum motor. (USA) An arrangement is described in which a motor is installed in the vacuum chamber enclosed in a vacuum sealed housing and having a magnetically coupled rotary feedthrough. Provision is made for