246 Classified Abstracts 593-607

iridium and are :

is coated with yttrium oxide. Operational ratings

Anode/collector voltage + 216V Cathode/collector voltage + 68 V Cathode emission current lOOmA Filament current 3A

The ionization current is measured with the help of a specially developed electronic circuit fitted with miniature valves and semiconductors. The gauge was calibrated with the help of a precision mercury manometer. Individual instrument calibra- tions were in satisfactory agreement over the pressure range 1-1O-6 torr. (U.S.S.R.)

E. A. Penchko et al., Pribory i Tekh. Eksper, (I), 1964, 146-151.

22 593. The geometry of viscosity, thermal conductivity and acoustic manometers. (Great Britain) A few years ago, viscosity manometers were improved by the introduction of negative feed-back, in analogy with the previous development of thermal conductivity manometers. The ampli- tude of oscillations of the sensing element or the temperature of, e.g., a hot wire, became thus independent of pressure. This new feature resulted in a very substantial increase in range and speed of response. However, the underlying physical phenomena are now more complex than in the older gauges. The present article aims at giving a unified description of both types of manometers. It deals principally with the geometrical aspects which have become the chief range-determining factor. The treatment has, however, been confined to pressures below those where a con- sideration of turbulence and convection becomes essential. (Sweden) (Author)

H. von Ubisch, Vaccum, 14 (3), March 1964,89-96.

594. A multipurpose mass spectrometer. (Germany) N. Warmoltz et al., Elecktronic, 13 (l), Jan 1964,5-10.

23. Plumbing

23 : 17 595. High vacuum insulated electrical feedthrough for use in cryostats. (U.S.A.) N. C. Einspruch and W. R. Wisseman, Rev. Sci. Znstr., 34 (8), Aug. 1963,929.

23 : 56 596. High vacuum thermocouples (molybdenum and kovar). (U.S.A.) J. E. Cox. Rev. Sci. Znstr., 34 (8), 1963, 931.

23 597. A cold high vacuum seal without gaskets. (U.S.A.) L. Mancebo, Proc. Z.E.E.E., 51 (9), Sept. 1963, 1250.

23 598. Vacuum proof joints are solderless. (Great Britain) Anon., Engng. News., 26 Sept. 1963,2.

24. Valves

599. Fast vacuum shutter (slide valve). (U.S.S.R.) 24

Description of two variants (one with vacuum rubber seal, the other with a fluorplastic seal) of a fast vacuum shutter for a pulsed ion source with small gas emission (- 1O-3 cm-3 per pulse). Time from start of opening to complete closing is approximately 5 msec., the exposed aperture being 16 mm in diameter. The shutter is operated by two electromagnets and uses a special synchronizing device. (U.S.S.R.)

0. V. Larov et al., Pribory i Tekh. Eksper., (3), May/June 1963, 131-133.

24 600. Protective self-sealing valve for vacuum systems. (U.S.S.R.) In order to ensure elimination of degassing products without a marked rise in pressure of the vacuum system, a special valve has been developed which opens when the pressure in the container reaches a definite value. A number of such valves with apertures ranging from 60 to 150 mm were tested. A special narrow seat construction ensures satisfactory tightness at lo-* torr. (U.S.S.R.)

A. V. Belonogov, Pribory i Tekh. Eksper., (l), 1964, 217-218.

26. Automatic Protective and Control Equipment 26

601. Automatic detection of low gas pressure in exchange cables. (U.S.A.) F. P. Plecolo, Bell Labs. Rec., 42 (l), Jan. 1964, 15-18.

26 602. Evaporated metal contacts on N-type epitaxial Si doped, designed for high speed use. (U.S.A.) L. H. Tolopko, Electronic News, 9 (415), Feb. 1964,4.

27. Leak Detectors and Leak Detection 27

603. High vacuum leak detector. (Great Britain) Anon., Engineering, 216 (5618), 27 Sept. 1963, 529.

27 604. Leak detector for vacuum equipment. (Great Britian) Anon., Engineer, 196 (5097), 27 Dec. 1963, 831.

28. Heating Equipment and Thermometers 28 : 30

605. Magnetic focus prevents thin film contamination. J. Rose, Electron Des. News, 9 (l), Jan. 1964, 39.

28 : 37 606. Continuous zone-refining apparatus. (U.S. A.) J. K. Kennedy, Rev. Sci. Znstrum., 35 (l), Jan. 1964,25-28.

28 : 48 607. Ceramic insulated vacuum tubes for very high frequency industrial heating. (U.S.A.) J. J. Behenna, Elect. Comm., 38 (3), 1963, 396.