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Nov 1965

Volume 2, Issue 6, pp. 293-310


Residual‐Gas Analysis of a DC-705 Oil‐Diffusion‐Pumped uhv System

Charles M. Gosselin and Paul J. Bryant

J. Vac. Sci. Technol. 2, 293 (1965); http://dx.doi.org/10.1116/1.1492439 (5 pages) | Cited 1 time

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The residual gases present in a DC-705 oil‐diffusion‐pump uhv system have been determined as a function of various trapping conditions. The system was equipped with a metal 2-in. oil‐diffusion pump in series with a specially designed trap in which zeolite was used. The configuration of the trap permitted the trapping zone to be immersed in cryogenic liquids, e.g., LN2. The effectiveness of the trap was determined as a function of temperature. A comparison of the residual gases is made for six conditions, including three trapping temperatures, while operating with zeolite and without zeolite.
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07.30.Bx Degasification, residual gas

Desorption–Adsorption of Residual Gases in Operating Electron‐Tube Components as Affected by Processing Techniques

M. Friedman Axler

J. Vac. Sci. Technol. 2, 298 (1965); http://dx.doi.org/10.1116/1.1492440 (4 pages)

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In a phenomenological investigation to determine the contribution to the gas ambient of traveling‐wave‐tube components operating in an environment simulating that of the actual tube, it was found that components comprising the gun assembly are the chief gas sources. Production‐type processing procedures for reducing the gas evolution from these operating components (vacuum firing and hydrogen firing before insertion into the final subassembly) were investigated, and correlation between the sorbed gas species and these processing techniques was obtained. It is shown that gas sorption characteristics of “the reversible methane cycle” during temperature cycling (reported in the literature) are due to the presence of nickel surfaces, but that this residual gas can be essentially eliminated by the prescribed processing procedure. All experiments were performed in an ultrahigh‐vacuum system with an omegatron mass spectrometer to measure partial pressures.
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84.47.+w Vacuum tubes
68.03.Fg Evaporation and condensation of liquids
68.43.Mn Adsorption kinetics

Relationships between Pumping Speed, Capture Probability, and Chamber Geometry in a Spherical Cryopumped Vacuum Chamber

Charles B. Hood and Carlisle B. Barnes

J. Vac. Sci. Technol. 2, 302 (1965); http://dx.doi.org/10.1116/1.1492441 (5 pages)

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A spherical cryopumped chamber with a test object is analyzed to determine the pumping speeds that will be observed with gauges located in various positions. Equations are developed to relate these speeds to chamber geometry and cryopump efficiency. It is shown that with a certain geometry and gauge location, speeds as high as four times the orifice speed, V̄∕4, per unit area can be observed with omni‐directional gauges, and even higher speeds can be observed with directional gauges.
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07.30.Kf Vacuum chambers, auxiliary apparatus, and materials

Diffusion–Sorption Pumping

P. L. Read and H. H. Glascock

J. Vac. Sci. Technol. 2, 307 (1965); http://dx.doi.org/10.1116/1.1492442 (2 pages)

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Abstract Unavailable
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07.30.Cy Vacuum pumps

A New Extreme High‐Vacuum Bakeable Valve

Peter J. Clarke

J. Vac. Sci. Technol. 2, 308 (1965); http://dx.doi.org/10.1116/1.1492443 (3 pages)

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Abstract Unavailable
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07.30.Kf Vacuum chambers, auxiliary apparatus, and materials
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