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Sensitive Helium Leak Detection in Cryogenic Vacuum Systems

  • M. G. Rao
Part of the A Cryogenic Engineering Conference Publication book series (ACRE, volume 41)

Abstract

Conventional leak detectors are not useful for cold leak detection of LHe cooled cryogenic vacuum systems since He is adsorbed onto the cold walls. Even though the He desorption leak detection system1 developed at the Continuous Electron Beam Accelerator Facility (CEBAF) is very sensitive, the cryogenic system needs to be warmed up to at least 10.5 K for leak detection purposes, and it still would be impossible to identify the location of the leak. Recently hot cathode extractor gauges have been found to be reliable, very useful and convenient for very low pressure measurement (10-14 torr) at LHe temperatures. This paper discusses the operation of extractor gauges at LHe temperatures and their in situ use for fast and convenient cold leak detection of cryogenic vacuum systems. Further, the location and identification of the leaks based on the principle of the pressure wave travel of He and time-of-flight measurements of the He signal are also discussed.

Keywords

Cold Wall Leak Detection Niobium Oxide Cold Extractor Technical Surface 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.

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References

  1. 1.
    M.G. Rao, Helium Desorption Leak Detection Method, J. Vac. Sci. Technol. A 11, 1598 (1993).CrossRefGoogle Scholar
  2. 2.
    M.G. Rao and P. Kneisel, The Use of Extractor Gauge at LHe Temperatures, CEB AF Tech Note #93-057, available from the Librarian, CEBAF, 12000 Jefferson Avenue, Newport News, VA 23606 USA.Google Scholar
  3. 3.
    M.G. Rao, Recent Advances in UHV Techniques for Particle Accelerators, CEBAF Tech Note #95-011, available from the Librarian, CEBAF, 12000 Jefferson Avenue, Newport News, VA 23606 USA.Google Scholar
  4. 4.
    J.G. Hengevoss, Gas Sorption by Surfaces Cooled to Low Temperatures, Trans. 3rd Int. Vac. Cong., Vol. 1, 51 (1965).Google Scholar
  5. 5.
    T.J. Lee, The condensation of H2 and D2: Astrophysics and Vacuum Technology, J. Vac. Sci. Technol. 9, 257 (1971).CrossRefGoogle Scholar
  6. 6.
    J.P. Hobson and K. M. Welch, Time-Dependent Helium and Hydrogen Pressure Profiles in a Long, Cryogenically Cooled Tube, Pumped at Periodic Intervals, J. Vac. Sci.Technol. A 11, 1566 (1993).CrossRefGoogle Scholar
  7. 7.
    M.G. Rao, P. Kneisel, and J. Susta, Cryosorption Pumping of H2 and He With Metals and Metal Oxides at 4.3 K, Cryogenics ICEC Supplement 34, 377 (1994).Google Scholar
  8. 8.
    M.G. Rao and W.C. Turner, to be published in J. Vac. Sci. Technol. Google Scholar
  9. 9.
    M.G. Kaganer, Proc. Acad. Sci. USSR Phys. Chem. Sect. 116, 603 (1957).Google Scholar

Copyright information

© Plenum Press, New York 1996

Authors and Affiliations

  • M. G. Rao
    • 1
  1. 1.Continuous Electron Beam Accelerator FacilityNewport NewsUSA

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