Journal of Low Temperature Physics

, Volume 53, Issue 5–6, pp 685–694 | Cite as

Ortho-para conversion of hydrogen in copper as origin of time-dependent heat leaks

  • M. Schwark
  • F. Pobell
  • W. P. Halperin
  • Ch. Buchal
  • J. Hanssen
  • M. Kubota
  • R. M. Mueller


It is shown that H2 precipitated into bubbles in copper undergoes ortho-para conversion. This conversion, at a rate of about 2%/h, and the hydrogen content are detected quantitatively by the time-dependent heat release associated with them. The heating is comparable to the time-dependent heat leak observed in copper nuclear refrigerators. The amount of H2 necessary to explain the data lies between 10 and 100 ppm. Due to its much smaller conversion rate and the smaller energy conversion, the heat released from D2 in copper is essentially time independent fort<100 h and is up to two orders of magnitude smaller than the one for H2.


Hydrogen Copper Magnetic Material Heat Release Conversion Rate 
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Copyright information

© Plenum Publishing Corporation 1983

Authors and Affiliations

  • M. Schwark
    • 1
  • F. Pobell
    • 1
  • W. P. Halperin
    • 1
    • 2
  • Ch. Buchal
    • 1
  • J. Hanssen
    • 1
  • M. Kubota
    • 1
  • R. M. Mueller
    • 1
  1. 1.Institut für FestkörperforschungKernforschungsanlage JülichJülichWest Germany
  2. 2.Department of Physics and Astronomy and Materials Research CenterNorthwestern UniversityEvanston

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