- Email: [email protected]
Laboratory vacuum furnace with exchange heating system
Classified
abstracts
293-308
secondary electron emission, the primary electron non-elastic reflection and the secondary electrons energy distribution, was studied. L A Ermolaev and B Kh Dvubua. Radiotekh Elektron. , 11 (91. ,,, Scot . 1966, 1724-1728
(in Russian>.
’
18 293. Positive column of helium discharge in a strong magnetic field. (USSR)
The transformation of a He discharge positive column from a laminar convection regime into a turbulent one and the turbulent regime structure were investigated. A V Nedospasov and S S Sobolev, Zh Tekh Fiz, 36 (IO), Ott 1966, 1758-l 767 (in Russian)
. 18
decay of discharge plasma with oscillating electrons in a strong magnetic field. (USSR) Presumably the causes of the anomalous quick decay of discharge plasma in a magnetic field with intensity higher than 10%Oe are the macroscopic turbulence and hf oscillation of plasma. The magnetic field critical values as a function of the pressure in the lOmato 10-l torr range are given. V G Grigorenko, Zh Tekh Fiz, 36 (lo), Ott 1966, 1800-1807 (in 294. Anomalous
Russian). 295. Ions mobility in own gas.
18 (USSR)
Equations for ion drift velocity in own gas are derived and calculated values are compared with those measured by other authors. B M Smimov, Zh Tekh Fiz, 36 (IO), Ott 1966,1864-1871 (in Russian). 18 : 31 2%. Influence of electrode material on the delay tbne of discharge at electrical breakdown in a vacuum gap. (USSR) An equation for the breakdown delay time is established. Satisfactory
calculations of these values are obtained for vacuum gaps wider than .02 inches, for narrower gaps the calculation may be used as a rough approximation. The influence of the residual gas pressure was not investigated. G M Kasslrov, Zh Tekh Fiz, 36 (IO), Ott 1966, 1883-1885 (in
301. Investigation of transmission secondary-electron emitters.
18 :30
(USSR) The preparation of transmission secondary-electron emitters is described. These consist of an A&O, grid or thin layer as a backing, Al intermediate layer and one or more secondary-emission layers of vacuum evaporated MgO or KCl. The best results were obtained with the porous KC1 layer of thickness 24 pm as an emitter (gain about 35 at 7 kV and at backing layer transparency 70 per cent). T Reichel and V Jares. Radiotekh Elektron. 11 (IO). Ott 1966. 18321836 (in Russian). 18 302. Charged particle flow to the cathode in a Penning type discharge. (USSR)
The direction and energy of the ions deposited on the centre of the cathode as a function of the magnetic field intensity, anode voltage and the pressure in the 1O-5 to 10d4 torr range were measured. GV Smirnitskaya and R. P Babertsyan, Radiotekh Elektron, 11 (IO), Ott 1966, 1897-1899
(in Russian).
18 volt-ampere characteristics of the leakage and emission current of sandwich cathodes. (Czechoslovakia) The influence of the thickness of the dielectric on the electrical properties of cathodes was investigated. Two different dielectrics (oxide and evaporated layers) were used, but no great difference was observed. V Balas, Czech J Phys, section B, 16 (7)) 1966, 569-577 (in English). 303. The
18
304. Ultrahigh vacuum apparatus for investigating film emission from a low-pressure mercury arc. (Germany)
The problems of pumping, wall materials and pressure measurement in ultrahigh vacuum apparatus (lo-’ to lo-@ torr) are discussed. The apparatus would be equally suitable for studying other problems of gas discharge physics. J Mitterauer, Elektrotech Maschinenbau, 83 (5), 1966, 308-311 (in German).
Russian). 18 297. Properties of a microwave discharge near plasma resonance. (USSR) The rapid increase of the 4713 A line intensity in a He discharge at
3 kMc was investigated. This effect is caused by changing the helium plasma resonance frequency at higher absorbed powers. A I Maksimov. Zh Tekh Fiz. 36 (IO). Ott 1966. 1894-1896 fin .., Russian).
18
298. Investigation of the speed of plasma extension at current break in
vacuum. (USSR) The speed of the plasma extension in a vacuum switch after breaking the dc current (30 to 1,000 A) was investigated. The speed of the plasma front is about 5 times higher than the speed of plasma during subsequent plasma arcing. MA Tyulina,Zh Tekh Fiz, 36 (IO), Ott 1966,1095-1908 (in Russian). 18 299. Excitation by Znd-ordercollisions in the radiation of N, and CO molecular hands from N,+ Ar, CO+ Ar mixtures in a glow discharge. (USSR) Mixtures argon and N, or CO with total pressures of 2 torr and N, or CO partial pressures of 0.02 to 1.98 torr, were prepared and subjected to a glow discharge. The influence of molecular bands corresponding to Znd-order collision excitation for the given partial pressures of N, and CO were determined and compared to calculated values. L A Chemenko, Zzv VUZ Fit, 9 (5)) 1966, 67-70 (in Russian). 18 300. Effect of crystal lattice thermal vibrations on ion-electron emission coe5cient. (USSR) The influence of temperature of Cu backing and of the angle of inci-
dence of bombarding ions on the ion-electron emission coefficient was investigated. Backings of Cu polycrystal and (110) and (111) faces of Cu single crystal were employed at temperatures 200 and 900°C bombarded by Ne, Ar and Kr ions with energies 30 keV. The effect of temperature was observed only on single crystal backings. I N Evdokimov et al, Fir Tverd Tela, 8 (ZO), Ott 1966, 2939-2944 (in Russian).
II. Vacuum apparatus and auxiliaries 20. Pumping
systems
20 305. The vacuum system of the MM II experiment. The MM II experimental assembly at Fontenay-aux-Roses was pumped down by a combination of oil diffusion pumps and titanium evaporation pumps on cold surfaces. New and larger equipment is being installed, aimed at providing a total pumping speed in excess of 106 litres/second. This vacuum system, the previous one, associated technical problems and some results of measurements are described. 2 Sledziewski and F Prevot, Euratom Information, 4 (IO), 1966, 1107, Rept (MF)
EUR 31OOe.
20 306. Vacuum furnace for high temperature fractural studies. (USA) An inexpensive vacuum furnace was constructed to study the high
temperature fracture of ceramic materials and was designed for use with an Instron testing machine. The vacuum chamber used is described and diagrams given. P L Gutshall and G D Swanson, Rev Sci Znstrum, 37,1966,1413-I414. 307. High vacuum aggregate HVAO-6/30/11.
20 (Germany)
The unit assembly described consists of a high vacuum oil diffusion pump with oil-vapour trap, programme valve, backing vacuum container and a magnetic backing pump valve. The pumping capacity is better than 30 litres/sec at lo-* torr. The pump is of the all-metal, three-stage fractionating type using oils with vapour pressure less than lo-’ torr at 25°C. Construction and operation of the various components are summarized. E Wagner and G Osterland, Jena Review, No 3, 1966, 185-186 (in English). 308. Laboratory vacuum furnace with exchange heating system. (Czechoslovakia)
20
Design details of a simple furnace, for vacuum annealing of Fe and other applications at lo-” torr in a chamber of volume 15 litres, are 111
Classified abstracts 309-317 presented. The system is pumped by a Hg diffusion pump with gettering H,O and O2 by PO and Ti. Samples can be heated up to 1,800”C by heat exchangers. V Kufudakis, Czech J Phys, section A, 16 (5), 1966,449-454 (in Czech). 309. Investigation of vacuum pumping on beds of soil material.
20 (USA)
The purpose of the investigation was to determine the pumping load and time required if beds of soil materials are placed in a vacuum chamber. The vacuum chamber had a volume of approximately four cubic feet and could be pumped down to lo-* torr when empty. Various sizes of soil beds were placed in the chamber. The beds were composed of either 500 micron or 5 micron particles of aluminium oxide. No particular difficulty was encountered in pumping beds of dry material (less than 0.1 percent moisture). A bed of fine material with 0.5 percent moisture erupted violently, due to sudden release of moisture from the bed. Anon, Aero Vat Corp Final Rept NASA-CR-66079, Feb 1966 (Troy New York). 20 310. An unconventional ultrahigh vacuum facility.
(USA)
To provide pressures of lO-‘O torr in a CTR subsidiary experiment, a vacuum vessel 2 ft in diameter and 8 ft long was fabricated and tested. Pumping was provided by conventional 6-in NRC diffusion pumps. Conventional water-cooled chevron-type baffles provided the only oil trapping between system and pumps. All valves were eliminated and seals were compression-type aluminium wire gaskets. Inside the stainless vessel was a copper liner heated during pumpdown to 100°C. Observations over several months of continuous pumping at static pressures of 5 x 10-Otorr revealed no visible traces of oil backstreaming from the pumps. Batch evaporation of Ti onto the liquid-nitrogencooled walls of the inner liner decreased the pressure approximately two orders of magnitude. Thermal cycling of the wall tempetatures produced no measurable pressure change. A residual gas analyzer was placed on the system to indicate pressures below 3 x 1O-lo torr and to measure the relative magnitude of the various mass peaks. Only small traces of the usual hydrocarbons were found: the predominant mass peak was 28. Increasing the pump heater power by 50 per cent produced no increase in the mass 28 peak, indicating a low level of silicon contamination in the system. E R Wells, Cahf Univ Proc 1965 Symp Eng Problems o.f Controlled Thermonuclear Res (Oak Ridge Lab Term); Rep CONF-650512. 20 : 47 311. Bakeout procedures for small glass ultrahigh vacuum systems. (USA) The performance of l-3 litre Pyrex glass ultrahigh vacuum systems was examined. A magnetic deflection type mass spectrometer was included for partial pressure measurements and Bayard-Alpert gauges and Schuemann photo-current suppressor gauges were used for total pressure measurements. The bakeout procedures for obtaining pressures below IO-” torr two to three days after exposing the system to atmospheric pressure are outlined. The main residual gas during bakeout and outgassing was CO; H1 became the major residual gas when the system was close to room temperature. The dominant partial pressure observed under aifferent conditions are presented for helium, hydrogen and carbon monoxide. The influence of processing upon CO production under 0, admission was also investigated. It was found that keeping the valve and the glass tubing between valve and trap at room temperature during bakeout results in oil condensation taking place. On the other hand if these are kept at about 150°C no oil condensation was noticed, and the CO pressure was only around 2 per cent of the 0, pressure under identical conditions. D Alpert, Rep NASA-CR-75681; R-286; AD-632596, April 1966 (Illinois
Univ Urbana, Coordinated
Science Lab).
21 :32 Determination of the vacuum system in a large accelerator. See abstract number 395. 21 312. New getter-ion pump of the orbitron type. (France) The construction and performance of the Orb-ion pump are described. Based on the orbitron principle, this non-magnetic ion pump affords high pumping speeds in the ultrahigh vacuum range with advantageous outgassing characteristics and stable inert gas pumping capacity. The pumping mechanism and technique of operation are discussed. The performance of the Orb-ion pump is shown to compare favourably with sputter-ion systems and combined mechanical and cryosorption pumped systems. The new pump is recommended for application in thin film deposition processes. C B Sibley and C Plaziat, Le Vide, 21 (124), Julv-Alrg 1966, 287-290 (in French). 313. Application of a turbomolecular pump in an electrostatic ator. (France)
Experience with a 140 litrelsecond turbomolecular pump applied to a 3MeV Van de Graaf electron accelerator is described. Advantages of this pumping method are claimed to be: low running costs; no pollution; simplicity of safety devices and automatic control; easy recovery of vacuum in extension pipes after air admittance: and the facility of pressure control in the accelerator tube (about 3 x 1O-e torr) by means of hydrogen admittance in the fore vacuum. Application of the turbomolecular pump to ion particle accelerators is possible but would require exceptionally good fore vacuum. R Gerbier and J Muel, Le Vide, 21 (I24/, July-Aug 1966, 283-286 (in French). 21 314. Water-jet pumps for chemical industry.
(Germany)
The extension of the application of water jet pumps to industrial scale operations is not merely a matter of sealing up the laboratory model. The industrial model described is independent of water pressure using a rotary jet system driven mechanically by direct connection to an electric motor. Both air and condensible gases may be pumped with condensation occurring inside the pump through the operation of suitable condenser incorporated in the unit. Generally 5 to 10 torr may be attained but combinations with jet-exhausters can provide 0.5 to 1 torr without the use of cooling brine. The possibility of using liquids with lower vapour pressure than water as pumping media is briefly considered. K Herbert, Vakuum-Technik, 15 (8), Ott 1966,192-196 (in German). 21 315. A radial flow turbomolecular vacuum pump.
(USA)
Designs, details, performance predictions, and performance measurements are summarized for a two-stage radial-flow turbopump used on the low pressure side of a diffusion pump, With the rotor turning at only 3400 rpm the radial flow turbopump described has a peak measured pumping speed of I. 1 x 10” litres/sec. at room temperature. E L Knuth and S F Iacobellis, Proc Intern Symp Rarefied Gas Dyn, 2, 1965. 225-238. LI
316. The basis of high vacuum pumps. I USA) Review of the fundamental principles of the 3 types of high vacuum pumps-diffusion, getter-ion and cryogenic. Relationships of the 3 pump types concerning pressure versus gas load, efficient operating range, and pumping system cost as a function of system size are graphed. Each type of pump is described and various configurations are indicated. It is shown that the selection of a pumping system should be based on an optimum compromise of chamber size, required evacuation time and process-gas loads. D B Arlidge, Machine Design, 38, 1966, 154-161. 317. Pumping speeds of getter-ion pumps at low pressures.
21. Pumps and pump fluids 21 : 32 Observations on the pumping system of the Saturn accelerator. See abstract number 392. 21 :32 Pumping problems and some solutions adopted in recent linear acceleration for particle beams. Sec. abstract number 393. 21 : 32 Construction of the vacuum chamber for a synchrotron. See abstract number 394. 112
21 :32 accelar-
21 122 (USA)
The pumping speed and discharge intensity measurements for a small getter-ion pump and the saturation effects for a diode and a triode type pump are discussed. Details of the apparatus are given. Pumping speeds at constant pressure were recorded over a period of one day through the pressure range IO-” to 10” torr. Field emission currents were found to reach a few hundred microamperes in the triode pump, and a few microamperes in the diode when pumping nitrogen. The gases used were hydrogen, helium and nitrogen. Graphs are presented for each gas for (1) the intensity vs pressure in the diode pump; (2) pumping speed and discharge intensity vs
abstracts
293-308
secondary electron emission, the primary electron non-elastic reflection and the secondary electrons energy distribution, was studied. L A Ermolaev and B Kh Dvubua. Radiotekh Elektron. , 11 (91. ,,, Scot . 1966, 1724-1728
(in Russian>.
’
18 293. Positive column of helium discharge in a strong magnetic field. (USSR)
The transformation of a He discharge positive column from a laminar convection regime into a turbulent one and the turbulent regime structure were investigated. A V Nedospasov and S S Sobolev, Zh Tekh Fiz, 36 (IO), Ott 1966, 1758-l 767 (in Russian)
. 18
decay of discharge plasma with oscillating electrons in a strong magnetic field. (USSR) Presumably the causes of the anomalous quick decay of discharge plasma in a magnetic field with intensity higher than 10%Oe are the macroscopic turbulence and hf oscillation of plasma. The magnetic field critical values as a function of the pressure in the lOmato 10-l torr range are given. V G Grigorenko, Zh Tekh Fiz, 36 (lo), Ott 1966, 1800-1807 (in 294. Anomalous
Russian). 295. Ions mobility in own gas.
18 (USSR)
Equations for ion drift velocity in own gas are derived and calculated values are compared with those measured by other authors. B M Smimov, Zh Tekh Fiz, 36 (IO), Ott 1966,1864-1871 (in Russian). 18 : 31 2%. Influence of electrode material on the delay tbne of discharge at electrical breakdown in a vacuum gap. (USSR) An equation for the breakdown delay time is established. Satisfactory
calculations of these values are obtained for vacuum gaps wider than .02 inches, for narrower gaps the calculation may be used as a rough approximation. The influence of the residual gas pressure was not investigated. G M Kasslrov, Zh Tekh Fiz, 36 (IO), Ott 1966, 1883-1885 (in
301. Investigation of transmission secondary-electron emitters.
18 :30
(USSR) The preparation of transmission secondary-electron emitters is described. These consist of an A&O, grid or thin layer as a backing, Al intermediate layer and one or more secondary-emission layers of vacuum evaporated MgO or KCl. The best results were obtained with the porous KC1 layer of thickness 24 pm as an emitter (gain about 35 at 7 kV and at backing layer transparency 70 per cent). T Reichel and V Jares. Radiotekh Elektron. 11 (IO). Ott 1966. 18321836 (in Russian). 18 302. Charged particle flow to the cathode in a Penning type discharge. (USSR)
The direction and energy of the ions deposited on the centre of the cathode as a function of the magnetic field intensity, anode voltage and the pressure in the 1O-5 to 10d4 torr range were measured. GV Smirnitskaya and R. P Babertsyan, Radiotekh Elektron, 11 (IO), Ott 1966, 1897-1899
(in Russian).
18 volt-ampere characteristics of the leakage and emission current of sandwich cathodes. (Czechoslovakia) The influence of the thickness of the dielectric on the electrical properties of cathodes was investigated. Two different dielectrics (oxide and evaporated layers) were used, but no great difference was observed. V Balas, Czech J Phys, section B, 16 (7)) 1966, 569-577 (in English). 303. The
18
304. Ultrahigh vacuum apparatus for investigating film emission from a low-pressure mercury arc. (Germany)
The problems of pumping, wall materials and pressure measurement in ultrahigh vacuum apparatus (lo-’ to lo-@ torr) are discussed. The apparatus would be equally suitable for studying other problems of gas discharge physics. J Mitterauer, Elektrotech Maschinenbau, 83 (5), 1966, 308-311 (in German).
Russian). 18 297. Properties of a microwave discharge near plasma resonance. (USSR) The rapid increase of the 4713 A line intensity in a He discharge at
3 kMc was investigated. This effect is caused by changing the helium plasma resonance frequency at higher absorbed powers. A I Maksimov. Zh Tekh Fiz. 36 (IO). Ott 1966. 1894-1896 fin .., Russian).
18
298. Investigation of the speed of plasma extension at current break in
vacuum. (USSR) The speed of the plasma extension in a vacuum switch after breaking the dc current (30 to 1,000 A) was investigated. The speed of the plasma front is about 5 times higher than the speed of plasma during subsequent plasma arcing. MA Tyulina,Zh Tekh Fiz, 36 (IO), Ott 1966,1095-1908 (in Russian). 18 299. Excitation by Znd-ordercollisions in the radiation of N, and CO molecular hands from N,+ Ar, CO+ Ar mixtures in a glow discharge. (USSR) Mixtures argon and N, or CO with total pressures of 2 torr and N, or CO partial pressures of 0.02 to 1.98 torr, were prepared and subjected to a glow discharge. The influence of molecular bands corresponding to Znd-order collision excitation for the given partial pressures of N, and CO were determined and compared to calculated values. L A Chemenko, Zzv VUZ Fit, 9 (5)) 1966, 67-70 (in Russian). 18 300. Effect of crystal lattice thermal vibrations on ion-electron emission coe5cient. (USSR) The influence of temperature of Cu backing and of the angle of inci-
dence of bombarding ions on the ion-electron emission coefficient was investigated. Backings of Cu polycrystal and (110) and (111) faces of Cu single crystal were employed at temperatures 200 and 900°C bombarded by Ne, Ar and Kr ions with energies 30 keV. The effect of temperature was observed only on single crystal backings. I N Evdokimov et al, Fir Tverd Tela, 8 (ZO), Ott 1966, 2939-2944 (in Russian).
II. Vacuum apparatus and auxiliaries 20. Pumping
systems
20 305. The vacuum system of the MM II experiment. The MM II experimental assembly at Fontenay-aux-Roses was pumped down by a combination of oil diffusion pumps and titanium evaporation pumps on cold surfaces. New and larger equipment is being installed, aimed at providing a total pumping speed in excess of 106 litres/second. This vacuum system, the previous one, associated technical problems and some results of measurements are described. 2 Sledziewski and F Prevot, Euratom Information, 4 (IO), 1966, 1107, Rept (MF)
EUR 31OOe.
20 306. Vacuum furnace for high temperature fractural studies. (USA) An inexpensive vacuum furnace was constructed to study the high
temperature fracture of ceramic materials and was designed for use with an Instron testing machine. The vacuum chamber used is described and diagrams given. P L Gutshall and G D Swanson, Rev Sci Znstrum, 37,1966,1413-I414. 307. High vacuum aggregate HVAO-6/30/11.
20 (Germany)
The unit assembly described consists of a high vacuum oil diffusion pump with oil-vapour trap, programme valve, backing vacuum container and a magnetic backing pump valve. The pumping capacity is better than 30 litres/sec at lo-* torr. The pump is of the all-metal, three-stage fractionating type using oils with vapour pressure less than lo-’ torr at 25°C. Construction and operation of the various components are summarized. E Wagner and G Osterland, Jena Review, No 3, 1966, 185-186 (in English). 308. Laboratory vacuum furnace with exchange heating system. (Czechoslovakia)
20
Design details of a simple furnace, for vacuum annealing of Fe and other applications at lo-” torr in a chamber of volume 15 litres, are 111
Classified abstracts 309-317 presented. The system is pumped by a Hg diffusion pump with gettering H,O and O2 by PO and Ti. Samples can be heated up to 1,800”C by heat exchangers. V Kufudakis, Czech J Phys, section A, 16 (5), 1966,449-454 (in Czech). 309. Investigation of vacuum pumping on beds of soil material.
20 (USA)
The purpose of the investigation was to determine the pumping load and time required if beds of soil materials are placed in a vacuum chamber. The vacuum chamber had a volume of approximately four cubic feet and could be pumped down to lo-* torr when empty. Various sizes of soil beds were placed in the chamber. The beds were composed of either 500 micron or 5 micron particles of aluminium oxide. No particular difficulty was encountered in pumping beds of dry material (less than 0.1 percent moisture). A bed of fine material with 0.5 percent moisture erupted violently, due to sudden release of moisture from the bed. Anon, Aero Vat Corp Final Rept NASA-CR-66079, Feb 1966 (Troy New York). 20 310. An unconventional ultrahigh vacuum facility.
(USA)
To provide pressures of lO-‘O torr in a CTR subsidiary experiment, a vacuum vessel 2 ft in diameter and 8 ft long was fabricated and tested. Pumping was provided by conventional 6-in NRC diffusion pumps. Conventional water-cooled chevron-type baffles provided the only oil trapping between system and pumps. All valves were eliminated and seals were compression-type aluminium wire gaskets. Inside the stainless vessel was a copper liner heated during pumpdown to 100°C. Observations over several months of continuous pumping at static pressures of 5 x 10-Otorr revealed no visible traces of oil backstreaming from the pumps. Batch evaporation of Ti onto the liquid-nitrogencooled walls of the inner liner decreased the pressure approximately two orders of magnitude. Thermal cycling of the wall tempetatures produced no measurable pressure change. A residual gas analyzer was placed on the system to indicate pressures below 3 x 1O-lo torr and to measure the relative magnitude of the various mass peaks. Only small traces of the usual hydrocarbons were found: the predominant mass peak was 28. Increasing the pump heater power by 50 per cent produced no increase in the mass 28 peak, indicating a low level of silicon contamination in the system. E R Wells, Cahf Univ Proc 1965 Symp Eng Problems o.f Controlled Thermonuclear Res (Oak Ridge Lab Term); Rep CONF-650512. 20 : 47 311. Bakeout procedures for small glass ultrahigh vacuum systems. (USA) The performance of l-3 litre Pyrex glass ultrahigh vacuum systems was examined. A magnetic deflection type mass spectrometer was included for partial pressure measurements and Bayard-Alpert gauges and Schuemann photo-current suppressor gauges were used for total pressure measurements. The bakeout procedures for obtaining pressures below IO-” torr two to three days after exposing the system to atmospheric pressure are outlined. The main residual gas during bakeout and outgassing was CO; H1 became the major residual gas when the system was close to room temperature. The dominant partial pressure observed under aifferent conditions are presented for helium, hydrogen and carbon monoxide. The influence of processing upon CO production under 0, admission was also investigated. It was found that keeping the valve and the glass tubing between valve and trap at room temperature during bakeout results in oil condensation taking place. On the other hand if these are kept at about 150°C no oil condensation was noticed, and the CO pressure was only around 2 per cent of the 0, pressure under identical conditions. D Alpert, Rep NASA-CR-75681; R-286; AD-632596, April 1966 (Illinois
Univ Urbana, Coordinated
Science Lab).
21 :32 Determination of the vacuum system in a large accelerator. See abstract number 395. 21 312. New getter-ion pump of the orbitron type. (France) The construction and performance of the Orb-ion pump are described. Based on the orbitron principle, this non-magnetic ion pump affords high pumping speeds in the ultrahigh vacuum range with advantageous outgassing characteristics and stable inert gas pumping capacity. The pumping mechanism and technique of operation are discussed. The performance of the Orb-ion pump is shown to compare favourably with sputter-ion systems and combined mechanical and cryosorption pumped systems. The new pump is recommended for application in thin film deposition processes. C B Sibley and C Plaziat, Le Vide, 21 (124), Julv-Alrg 1966, 287-290 (in French). 313. Application of a turbomolecular pump in an electrostatic ator. (France)
Experience with a 140 litrelsecond turbomolecular pump applied to a 3MeV Van de Graaf electron accelerator is described. Advantages of this pumping method are claimed to be: low running costs; no pollution; simplicity of safety devices and automatic control; easy recovery of vacuum in extension pipes after air admittance: and the facility of pressure control in the accelerator tube (about 3 x 1O-e torr) by means of hydrogen admittance in the fore vacuum. Application of the turbomolecular pump to ion particle accelerators is possible but would require exceptionally good fore vacuum. R Gerbier and J Muel, Le Vide, 21 (I24/, July-Aug 1966, 283-286 (in French). 21 314. Water-jet pumps for chemical industry.
(Germany)
The extension of the application of water jet pumps to industrial scale operations is not merely a matter of sealing up the laboratory model. The industrial model described is independent of water pressure using a rotary jet system driven mechanically by direct connection to an electric motor. Both air and condensible gases may be pumped with condensation occurring inside the pump through the operation of suitable condenser incorporated in the unit. Generally 5 to 10 torr may be attained but combinations with jet-exhausters can provide 0.5 to 1 torr without the use of cooling brine. The possibility of using liquids with lower vapour pressure than water as pumping media is briefly considered. K Herbert, Vakuum-Technik, 15 (8), Ott 1966,192-196 (in German). 21 315. A radial flow turbomolecular vacuum pump.
(USA)
Designs, details, performance predictions, and performance measurements are summarized for a two-stage radial-flow turbopump used on the low pressure side of a diffusion pump, With the rotor turning at only 3400 rpm the radial flow turbopump described has a peak measured pumping speed of I. 1 x 10” litres/sec. at room temperature. E L Knuth and S F Iacobellis, Proc Intern Symp Rarefied Gas Dyn, 2, 1965. 225-238. LI
316. The basis of high vacuum pumps. I USA) Review of the fundamental principles of the 3 types of high vacuum pumps-diffusion, getter-ion and cryogenic. Relationships of the 3 pump types concerning pressure versus gas load, efficient operating range, and pumping system cost as a function of system size are graphed. Each type of pump is described and various configurations are indicated. It is shown that the selection of a pumping system should be based on an optimum compromise of chamber size, required evacuation time and process-gas loads. D B Arlidge, Machine Design, 38, 1966, 154-161. 317. Pumping speeds of getter-ion pumps at low pressures.
21. Pumps and pump fluids 21 : 32 Observations on the pumping system of the Saturn accelerator. See abstract number 392. 21 :32 Pumping problems and some solutions adopted in recent linear acceleration for particle beams. Sec. abstract number 393. 21 : 32 Construction of the vacuum chamber for a synchrotron. See abstract number 394. 112
21 :32 accelar-
21 122 (USA)
The pumping speed and discharge intensity measurements for a small getter-ion pump and the saturation effects for a diode and a triode type pump are discussed. Details of the apparatus are given. Pumping speeds at constant pressure were recorded over a period of one day through the pressure range IO-” to 10” torr. Field emission currents were found to reach a few hundred microamperes in the triode pump, and a few microamperes in the diode when pumping nitrogen. The gases used were hydrogen, helium and nitrogen. Graphs are presented for each gas for (1) the intensity vs pressure in the diode pump; (2) pumping speed and discharge intensity vs