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Manufacture of vacuum vessels for the Nina synchrotron
Classified
abstracts
1464-1472
primary electron beam pulse of 5 to 20 psec; repetition rate of 0.3 to 3 impulses/see; time for measurement of one value, IO set; and 0.6 per cent error. Measured values are not given. L F Afonina and G B Stuchinskiy, Pribor_r Tekh Eksper, 11 (2), March-April 1967, 231-232 (in Russian).
calculated for a given system of anode cells of equal length. With the calculated configuration the pumping speed should approach the maximum possible for the given anode system. H Roth and B Wenzel, Vakuum-Technik, 16 (6), June 1967, 131-133 (in German). LL
1469. Some characteristics
II. Vacuum 20. PUMPING
apparatus
and auxiliaries
SYSTEMS
20 : 30 1464. Evaporator for operation at high or ultrahigh vacuum with automatic pumping system. (France) A complete evaporator system is described which is suitable for production-scale, thin film deposition under high or ultrahigh vacuum. The system is oil diffusion pumped with a water-cooled baffle and a liquid nitrogen trap. With Viton seals and a by-pass, valve pressures of 1Om8torr may be maintained, by baking once every 24 hours (overnight) to 350°C. If baking to 350°C is carried out before each operating cycle, pressures down to lOmy torr may be obtained. Ultrahigh vacuum down to lo-r3 torr is achieved using gold sealing rings with baking to 450°C. Some comparative performance data are presented for the system operating with the by-pass valve and with or without a titanium sublimation pump. H Reisinger, Le Vide, 22 (128), March-April 1967, 95-97 (in French). 1465. Ultrahigh vacuum evaporators for the production of active (France) semiconductor elements using ion-pumped systems.
The development of an ultrahigh vacuum pumping system, combining an ion pump, a titanium sublimation pump and a liquid nitrogen cooled cryopanel, is described. The assembly has an overall pumping speed of over 3000 litres/sec. Using this system, the problems of maintaining ultrahigh vacuum during evaporation processes were investigated with partial pressure measurement by a quadrupole gas analyzer. Some novel techniques using the quadrupole analyzer are developed to determine ion spectra originating from the evaporated materials. A Varon and M Desforges, Le Vi&, 22 (128), March-April 1967, 105-109
(in French). 20
1466. Manufacture
of vacuum vessels for the Nina synchrotron. (USA) A manufacturing procedure is described for a vacuum chamber fabricated by using joints of a glass-impregnated, hot-setting epoxy resin. The vacuum chamber used for an electron synchrotron required bonding of the resin to both stainless steel and titanium for operation at 1Om8tort-. C J Hart, Nucl Eng, 12, 1967, 115-l 17. LU
1467. Coreless vacuum induction furnace. (Great Britain) Used for melting and/or holding large capacity charges, the furnace comprises a primary induction coil surrounding the furnace crucible, with a vacuum seal consisting of a sleeve of gas-impermeable material of low electrical and magnetic conductivity between the coil and crucible, and with gastight upper and lower closures arranged to close the upper and lower ends, respectively, of the vacuum seal to form a vacuum chamber housing the crucible. A coil for the passage of cooling liquid is disposed close to the inner surface of at least a portion of the sleeve, and the upper closure comprises at least one inner cover of refractory material positioned with the vacuum chamber to close the crucible and at least one outer gas-impermeable lid closing the vacuum chamber. Suitably, the sleeve of gas-impermeable material is composed of a synthetic plastics material or plasticsimpregnated paper. 0 Junker, Brit Patents 1,067,323-6, Patent Abstr, 7 (21) part 7, 26th Ma)’ 1967, 2 and 3. 21. PUMPS
AND PUMP
1468. Dimensioning Part 2. (Germany)
of
FLUIDS
getter-ion
pumps
of
rotational
21 symmetry.
On a basis of the equations derived in the first part of this paper, the optimum shape of the anode housing in a diode ion pump is 534
of a cryopump.
(Japan) Some characteristics of a recently developed cryopump were studied as part of a series of investigations on the application of cryogenics to high-vacuum, eg as a pumping method for an ultrahigh vacuum thin film evaporator. The cryogenerator is composed of six heat exchangers, an expansion engine (reciprocating type), and two JouleThomson valves. Cold generated by this apparatus was measured as 10 watts at 4.2”K. The generator can also be used as a helium liquefier. The cryopanel, of diameter 200 mm, cooled by the cryogenerator, can be refrigerated down to 8-12”K, within two hours after starting, and the ultimate pressure was measured as 9.8 x 10mB torr by Bayard-Alpert gauge, and 1.13 x 1Oms torr by Redhead magnetron gauge. The relation between pressure and cryopanel temperature was determined, and composition of the residual gas was analysed. The ultimate pressure was found to be principally dependent on the hydrogen concentration in the ultrahigh vacuum region. The pumping speed was measured as 3.0 litre/sec cm2 for nitrogen gas in pressure range of lo-’ to 10m4 torr, and was not affected by the deposited solid nitrogen film even at a thickness of 1.7 mm. K Nishida et al, J Vat Sot Japan, 10 (2), 63-68, (in Japanese). 21 1470. Ultimate vacuum characteristics of a Hickman pump. (Japan) Ultimate pressure vs input characteristics of a Hickman pump (fractionating oil diffusion) containing Octoil S and DC-705 as working fluids, were observed as a function of operating time and backing pressure. It is shown that in both cases the characteristics vary markedly, depending on the oil, as the pump is operated for several hundred hours. It is confirmed that the important pressurelimiting factors are back-diffusion of gases from fore-vacuum and thermal decomposition of impurity of unstable components in the oil as well as outgassing of the system. With DC-705, the lowest pressures were obtained with an input for which pumping of the oil occurs continuously. Pressure burst due to pumping was not observed for any boiler (except for a non-volatile-reserving boiler) over the entire range of input tested. The lowest utlimate pressure is not affected by changing a backing pressure from 1O-3 to 1Om8torr, so long as input is optimum. The lowest pressure obtained was 4x 10-l” torr without cooling a trap. The good heat-resistance of DC-705 was confirmed by these experiments. K Ishikawa and T Yamaguchi, J Vat Sot Japan, 10 (4), 1967, 1388145 (in Japanese). LI
1471. Ultimate pressures in the adsorption nitrogen cooled, active charcoal. (USSR)
pumping
of air by liquid
A 0.5 litre volume glass cylinder with two hot cathode ionization gauges, containing 30g of type BAU charcoal was mechanically pumped to lO-a torr, followed by total immersion in liquid nitrogen. A pressure of 5 x 10-O torr was obtained. After baking at 300°C and 1O-4 torr, to minimize degassing or the glass walls, immersion in liquid nitrogen resulted in pressures of 8 x 1Om1otorr. The pumping effect of the gauges, which has an important influence on the ultimate pressures, were not taken into account. B G Lazarev et al, Pribory Tekh Eksper, 11(2), March-April 1967,220221 (in Russian). 21 1472. Investigations on ion-getter pumps for magnetic electric discharge with titanium cathode. (Hungary)
The cold-cathode magnetic electric ion pump is preferred to oil and mercury diffusion pumps in systems requiring ultrahigh purity, such as particle accelerators, metal film evaporators, atom and ion collision measurements, semi-conductor detector manufacture and mass spectroscopy. The pump consists of a titanium cathode, a 1200 gauss magnetic field obtained with anisotropic barrium ferrite permanent magnet and an activated carbon-filled adsorption-type backing vacuum pump. Pumping velocity depends on the field strength at constant magnetic field, and is constant at 1O-5 to lo-’ tort-. The ion pump has lower energy consumption than conventional diffusion pumps of equal capacity. L Valyi, Kozlem, 14, 1966, 401408 (in Hungarian).
abstracts
1464-1472
primary electron beam pulse of 5 to 20 psec; repetition rate of 0.3 to 3 impulses/see; time for measurement of one value, IO set; and 0.6 per cent error. Measured values are not given. L F Afonina and G B Stuchinskiy, Pribor_r Tekh Eksper, 11 (2), March-April 1967, 231-232 (in Russian).
calculated for a given system of anode cells of equal length. With the calculated configuration the pumping speed should approach the maximum possible for the given anode system. H Roth and B Wenzel, Vakuum-Technik, 16 (6), June 1967, 131-133 (in German). LL
1469. Some characteristics
II. Vacuum 20. PUMPING
apparatus
and auxiliaries
SYSTEMS
20 : 30 1464. Evaporator for operation at high or ultrahigh vacuum with automatic pumping system. (France) A complete evaporator system is described which is suitable for production-scale, thin film deposition under high or ultrahigh vacuum. The system is oil diffusion pumped with a water-cooled baffle and a liquid nitrogen trap. With Viton seals and a by-pass, valve pressures of 1Om8torr may be maintained, by baking once every 24 hours (overnight) to 350°C. If baking to 350°C is carried out before each operating cycle, pressures down to lOmy torr may be obtained. Ultrahigh vacuum down to lo-r3 torr is achieved using gold sealing rings with baking to 450°C. Some comparative performance data are presented for the system operating with the by-pass valve and with or without a titanium sublimation pump. H Reisinger, Le Vide, 22 (128), March-April 1967, 95-97 (in French). 1465. Ultrahigh vacuum evaporators for the production of active (France) semiconductor elements using ion-pumped systems.
The development of an ultrahigh vacuum pumping system, combining an ion pump, a titanium sublimation pump and a liquid nitrogen cooled cryopanel, is described. The assembly has an overall pumping speed of over 3000 litres/sec. Using this system, the problems of maintaining ultrahigh vacuum during evaporation processes were investigated with partial pressure measurement by a quadrupole gas analyzer. Some novel techniques using the quadrupole analyzer are developed to determine ion spectra originating from the evaporated materials. A Varon and M Desforges, Le Vi&, 22 (128), March-April 1967, 105-109
(in French). 20
1466. Manufacture
of vacuum vessels for the Nina synchrotron. (USA) A manufacturing procedure is described for a vacuum chamber fabricated by using joints of a glass-impregnated, hot-setting epoxy resin. The vacuum chamber used for an electron synchrotron required bonding of the resin to both stainless steel and titanium for operation at 1Om8tort-. C J Hart, Nucl Eng, 12, 1967, 115-l 17. LU
1467. Coreless vacuum induction furnace. (Great Britain) Used for melting and/or holding large capacity charges, the furnace comprises a primary induction coil surrounding the furnace crucible, with a vacuum seal consisting of a sleeve of gas-impermeable material of low electrical and magnetic conductivity between the coil and crucible, and with gastight upper and lower closures arranged to close the upper and lower ends, respectively, of the vacuum seal to form a vacuum chamber housing the crucible. A coil for the passage of cooling liquid is disposed close to the inner surface of at least a portion of the sleeve, and the upper closure comprises at least one inner cover of refractory material positioned with the vacuum chamber to close the crucible and at least one outer gas-impermeable lid closing the vacuum chamber. Suitably, the sleeve of gas-impermeable material is composed of a synthetic plastics material or plasticsimpregnated paper. 0 Junker, Brit Patents 1,067,323-6, Patent Abstr, 7 (21) part 7, 26th Ma)’ 1967, 2 and 3. 21. PUMPS
AND PUMP
1468. Dimensioning Part 2. (Germany)
of
FLUIDS
getter-ion
pumps
of
rotational
21 symmetry.
On a basis of the equations derived in the first part of this paper, the optimum shape of the anode housing in a diode ion pump is 534
of a cryopump.
(Japan) Some characteristics of a recently developed cryopump were studied as part of a series of investigations on the application of cryogenics to high-vacuum, eg as a pumping method for an ultrahigh vacuum thin film evaporator. The cryogenerator is composed of six heat exchangers, an expansion engine (reciprocating type), and two JouleThomson valves. Cold generated by this apparatus was measured as 10 watts at 4.2”K. The generator can also be used as a helium liquefier. The cryopanel, of diameter 200 mm, cooled by the cryogenerator, can be refrigerated down to 8-12”K, within two hours after starting, and the ultimate pressure was measured as 9.8 x 10mB torr by Bayard-Alpert gauge, and 1.13 x 1Oms torr by Redhead magnetron gauge. The relation between pressure and cryopanel temperature was determined, and composition of the residual gas was analysed. The ultimate pressure was found to be principally dependent on the hydrogen concentration in the ultrahigh vacuum region. The pumping speed was measured as 3.0 litre/sec cm2 for nitrogen gas in pressure range of lo-’ to 10m4 torr, and was not affected by the deposited solid nitrogen film even at a thickness of 1.7 mm. K Nishida et al, J Vat Sot Japan, 10 (2), 63-68, (in Japanese). 21 1470. Ultimate vacuum characteristics of a Hickman pump. (Japan) Ultimate pressure vs input characteristics of a Hickman pump (fractionating oil diffusion) containing Octoil S and DC-705 as working fluids, were observed as a function of operating time and backing pressure. It is shown that in both cases the characteristics vary markedly, depending on the oil, as the pump is operated for several hundred hours. It is confirmed that the important pressurelimiting factors are back-diffusion of gases from fore-vacuum and thermal decomposition of impurity of unstable components in the oil as well as outgassing of the system. With DC-705, the lowest pressures were obtained with an input for which pumping of the oil occurs continuously. Pressure burst due to pumping was not observed for any boiler (except for a non-volatile-reserving boiler) over the entire range of input tested. The lowest utlimate pressure is not affected by changing a backing pressure from 1O-3 to 1Om8torr, so long as input is optimum. The lowest pressure obtained was 4x 10-l” torr without cooling a trap. The good heat-resistance of DC-705 was confirmed by these experiments. K Ishikawa and T Yamaguchi, J Vat Sot Japan, 10 (4), 1967, 1388145 (in Japanese). LI
1471. Ultimate pressures in the adsorption nitrogen cooled, active charcoal. (USSR)
pumping
of air by liquid
A 0.5 litre volume glass cylinder with two hot cathode ionization gauges, containing 30g of type BAU charcoal was mechanically pumped to lO-a torr, followed by total immersion in liquid nitrogen. A pressure of 5 x 10-O torr was obtained. After baking at 300°C and 1O-4 torr, to minimize degassing or the glass walls, immersion in liquid nitrogen resulted in pressures of 8 x 1Om1otorr. The pumping effect of the gauges, which has an important influence on the ultimate pressures, were not taken into account. B G Lazarev et al, Pribory Tekh Eksper, 11(2), March-April 1967,220221 (in Russian). 21 1472. Investigations on ion-getter pumps for magnetic electric discharge with titanium cathode. (Hungary)
The cold-cathode magnetic electric ion pump is preferred to oil and mercury diffusion pumps in systems requiring ultrahigh purity, such as particle accelerators, metal film evaporators, atom and ion collision measurements, semi-conductor detector manufacture and mass spectroscopy. The pump consists of a titanium cathode, a 1200 gauss magnetic field obtained with anisotropic barrium ferrite permanent magnet and an activated carbon-filled adsorption-type backing vacuum pump. Pumping velocity depends on the field strength at constant magnetic field, and is constant at 1O-5 to lo-’ tort-. The ion pump has lower energy consumption than conventional diffusion pumps of equal capacity. L Valyi, Kozlem, 14, 1966, 401408 (in Hungarian).