- Email: [email protected]
High-vacuum pump for gas evacuation
Classified abstracts 909-919 system are reviewed. The methods vary from direct measurements, by weight or volume, of backstreaming pump oil to the conversion of organic vapours into another form which is then measured. The writer changed the organic vapours into polymer films by the interaction of electrons with organic molecules while they are absorbed on a glass surface. The thickness of the resultant polymer films were measured by interferometry. The technique and the results obtained from three typical vacuum systems are discussed. (Great
Britain) L Laurensou, Le Vide, 20 (117), May-June 1965, 211-221. 22 : 27 909. Calibration of an ionization gauge using a variable conductance method. (France) The authors have presented a systematic usage of a fundamental method with regard to the metrology of low pressures. A method is described for the measurement of the pumping speed of diffusion pumps derived from Oatley's method and based on the use of a variable conductance in a continuous way. The effect of various parameters on the accuracy of such a system is discussed. This method was used to check the calibration of an Afnor gauge, as well as a Bayard-Alpert Ultravac gauge. P S Chonrmoff and B Aubry, Le Vide, 20 (117), May-June 1965,
177-185. 22 : 27 910. Interferometric differential manometer. Peube's system.
(France) An apparatus to be used for the absolute measurements of total pressure between 3 × 10 -1 and 10-5 torr is described. It Consists of two chambers containing a liquid at low vapour pressure: one of the chambers is at very low pressure, and one measures the difference in level of the liquid in the second (measuring) chamber by using an interferometric system of Perot-Fabry type. Using monochromatic light, the difference in pressure is given by ziP = oJA8 n- ~0" The linearity of response as well as the absence of hysteresis has been checked. Precisions of 1.965 × 10 -6 torr using an oil and 2.43 × 10-5 torr using a mercury-oil system are reported. B Auhry and R Delbart, Le Vide, 20 (117), May-June 1965, 194-199.
having rated speeds from 40 litres/sec up to 20,000 litres/sec. Removal of heat from the thermoelectric battery is effected by water from the pump cooling system. The traps are arranged to provide double reflection of vapour molecules from the condensation surfaces and consequently the number of oil vapour molecules that penetrate through the trap into the pumped volume is relatively very small. The requirement that the trap should not appreciably reduce the pumping speed is also taken into consideration. For all types of traps the condensation surface temperature of the second stage is --50 ° to --52°C with a water temperature of ÷ 18°C. The maximum drop in temperature provided by the thermoelectric battery is 70 °C. The trap assembly can readily be dismantled for cleaning purposes. E A Kolenko, Bull Tekh-Ekon RSFSR No 2, 43--44, (in Russian).
27. Leak detectors and leak detection 27 : 22 Calibration of an ionization gauge using a variable conductance method. See abstract number 909. 27 : 22 Interferometric differential manometer. Peube's system. See abstract number 910. 27 : 56 916. Simplifying leak detection. (USA) The author discusses some of the advantages and disadvantages of the electronic method of leak detection as compared with the use of the helium mass spectrometer. Whereas the detection of leaks in components is easily performed with a mass spectrometer, the detection of leaks in systems often presents several problems. For instance, pumping down to the appropriate pressure can be tedious, contamination of the spectrometer itself with impurities from the system or of the background due to protracted probing over large areas all upset the sensitivity of the method. In contrast, electronic amplification of gauge deflections caused by probe gas or liquid entering a small leak, provides a method which is effective at virtually any pressure and which gives a very rapid response under most conditions. Obviously it cannot be calibrated to show leak rate but it can cost only one tenth of the helium mass spectrometer.
( USA )
23. Plumbing
F Munro, Research~Development, 16 (7), July 1965, 50-52. 23
911. Linking units for pipe systems. (France) The authors describe a pipe junction system with collars and clips. Besides the normal advantages it has possibilities for coupling to standard flanges. J Amoignon and M L6v6que, Le Vide, 20 (117), May-June 1965,
222-225.
25. Baffles, traps and refrigeration equipment 25:2l High-vacuum pump for gas evacuation. See abstract number 892. 25 : 21 Method of producing a vacuum. See abstract number 893. 25 : 22 : 34 Measurements in situ of the baekstreaming of oil by the mierovolumetric determination of drops. See abstract number 907. 25 912. Experimental study of a cryogenic baffle for a large space simulation facility. (France) M H Hablaniah, CIVRES, (2), Paris, 1964, SF1TV. 25 913. A simple helium-3 cryostat for specific heat measurements between 0.4 and 4.2°K. (Great Britain) R G Scnrlock and E M Wray, J scient lnstrum, 42 (6), June 1965,
421-424. 25 914. Economical liquid helium cryostat and other cryogenic apparatus. (USA) J E Whitehouse et al, Rev scient lnstrum, 36 (6), June 1965,
768-771.
28. Heating equipment and thermometers 28 917. The dependance of sensitivity and signal efficiency on the size of reception surface of vacuum thermocouples. (DDR) Two types of reaction of thermocouples relating to photosensitivity are described, the first involving a single thermocouple and the second a thermopile with the single elements connected either in series or in parallel. H Kortum, Feingeriite-Tech, 14 (4), April 1965, 145-149.
29. Miscellaneous 29 : 39 Method and apparatus far producing vacuum packages for food. See abstract number 933.
III. Vacuum applications 30. Evaporation and sputtering 30:18 Sorption of argon ions by titanium films. See abstract number 882. 3O 918. Vaponr-deposited thin-film piezoelectric transducers. (USA) J DeKlerk and E F Kelly, Rev Scient Instrum, 36 (4), April 1965,
506-510.
25
30 : 41 919. Measurement of the thickness of epitaxial films on silicon.
915. High vacuum traps with thermoelectric cooling. (USSR) Particulars are given of a range of thermoelectrically-operated cold traps suitable for use with all USSR types of vapour-jet pumps
A method is described which enables the thickness to be determined of an epitaxial film on silicon deposited from the vapour
(USSR)
563
Britain) L Laurensou, Le Vide, 20 (117), May-June 1965, 211-221. 22 : 27 909. Calibration of an ionization gauge using a variable conductance method. (France) The authors have presented a systematic usage of a fundamental method with regard to the metrology of low pressures. A method is described for the measurement of the pumping speed of diffusion pumps derived from Oatley's method and based on the use of a variable conductance in a continuous way. The effect of various parameters on the accuracy of such a system is discussed. This method was used to check the calibration of an Afnor gauge, as well as a Bayard-Alpert Ultravac gauge. P S Chonrmoff and B Aubry, Le Vide, 20 (117), May-June 1965,
177-185. 22 : 27 910. Interferometric differential manometer. Peube's system.
(France) An apparatus to be used for the absolute measurements of total pressure between 3 × 10 -1 and 10-5 torr is described. It Consists of two chambers containing a liquid at low vapour pressure: one of the chambers is at very low pressure, and one measures the difference in level of the liquid in the second (measuring) chamber by using an interferometric system of Perot-Fabry type. Using monochromatic light, the difference in pressure is given by ziP = oJA8 n- ~0" The linearity of response as well as the absence of hysteresis has been checked. Precisions of 1.965 × 10 -6 torr using an oil and 2.43 × 10-5 torr using a mercury-oil system are reported. B Auhry and R Delbart, Le Vide, 20 (117), May-June 1965, 194-199.
having rated speeds from 40 litres/sec up to 20,000 litres/sec. Removal of heat from the thermoelectric battery is effected by water from the pump cooling system. The traps are arranged to provide double reflection of vapour molecules from the condensation surfaces and consequently the number of oil vapour molecules that penetrate through the trap into the pumped volume is relatively very small. The requirement that the trap should not appreciably reduce the pumping speed is also taken into consideration. For all types of traps the condensation surface temperature of the second stage is --50 ° to --52°C with a water temperature of ÷ 18°C. The maximum drop in temperature provided by the thermoelectric battery is 70 °C. The trap assembly can readily be dismantled for cleaning purposes. E A Kolenko, Bull Tekh-Ekon RSFSR No 2, 43--44, (in Russian).
27. Leak detectors and leak detection 27 : 22 Calibration of an ionization gauge using a variable conductance method. See abstract number 909. 27 : 22 Interferometric differential manometer. Peube's system. See abstract number 910. 27 : 56 916. Simplifying leak detection. (USA) The author discusses some of the advantages and disadvantages of the electronic method of leak detection as compared with the use of the helium mass spectrometer. Whereas the detection of leaks in components is easily performed with a mass spectrometer, the detection of leaks in systems often presents several problems. For instance, pumping down to the appropriate pressure can be tedious, contamination of the spectrometer itself with impurities from the system or of the background due to protracted probing over large areas all upset the sensitivity of the method. In contrast, electronic amplification of gauge deflections caused by probe gas or liquid entering a small leak, provides a method which is effective at virtually any pressure and which gives a very rapid response under most conditions. Obviously it cannot be calibrated to show leak rate but it can cost only one tenth of the helium mass spectrometer.
( USA )
23. Plumbing
F Munro, Research~Development, 16 (7), July 1965, 50-52. 23
911. Linking units for pipe systems. (France) The authors describe a pipe junction system with collars and clips. Besides the normal advantages it has possibilities for coupling to standard flanges. J Amoignon and M L6v6que, Le Vide, 20 (117), May-June 1965,
222-225.
25. Baffles, traps and refrigeration equipment 25:2l High-vacuum pump for gas evacuation. See abstract number 892. 25 : 21 Method of producing a vacuum. See abstract number 893. 25 : 22 : 34 Measurements in situ of the baekstreaming of oil by the mierovolumetric determination of drops. See abstract number 907. 25 912. Experimental study of a cryogenic baffle for a large space simulation facility. (France) M H Hablaniah, CIVRES, (2), Paris, 1964, SF1TV. 25 913. A simple helium-3 cryostat for specific heat measurements between 0.4 and 4.2°K. (Great Britain) R G Scnrlock and E M Wray, J scient lnstrum, 42 (6), June 1965,
421-424. 25 914. Economical liquid helium cryostat and other cryogenic apparatus. (USA) J E Whitehouse et al, Rev scient lnstrum, 36 (6), June 1965,
768-771.
28. Heating equipment and thermometers 28 917. The dependance of sensitivity and signal efficiency on the size of reception surface of vacuum thermocouples. (DDR) Two types of reaction of thermocouples relating to photosensitivity are described, the first involving a single thermocouple and the second a thermopile with the single elements connected either in series or in parallel. H Kortum, Feingeriite-Tech, 14 (4), April 1965, 145-149.
29. Miscellaneous 29 : 39 Method and apparatus far producing vacuum packages for food. See abstract number 933.
III. Vacuum applications 30. Evaporation and sputtering 30:18 Sorption of argon ions by titanium films. See abstract number 882. 3O 918. Vaponr-deposited thin-film piezoelectric transducers. (USA) J DeKlerk and E F Kelly, Rev Scient Instrum, 36 (4), April 1965,
506-510.
25
30 : 41 919. Measurement of the thickness of epitaxial films on silicon.
915. High vacuum traps with thermoelectric cooling. (USSR) Particulars are given of a range of thermoelectrically-operated cold traps suitable for use with all USSR types of vapour-jet pumps
A method is described which enables the thickness to be determined of an epitaxial film on silicon deposited from the vapour
(USSR)
563