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

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

37 Scopus citations


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 for t<100 h and is up to two orders of magnitude smaller than the one for H2.

Original languageEnglish (US)
Pages (from-to)685-694
Number of pages10
JournalJournal of Low Temperature Physics
Issue number5-6
StatePublished - Dec 1983

ASJC Scopus subject areas

  • Atomic and Molecular Physics, and Optics
  • General Materials Science
  • Condensed Matter Physics


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