Ultracold neutron upscattering rates in a molecular deuterium crystal

C. Liu, A. Young, S. Lamoreaux

Research output: Contribution to journalArticlepeer-review


A calculation of ultracold neutron (UCN) upscattering rates in molecular deuterium solids has been carried out, taking into account intramolecular excitations and phonons. The different molecular species ortho-(Formula presented) (with even rotational quantum number J) and para-(Formula presented) (with odd J) exhibit significantly different UCN-phonon annihilation cross sections. Para- to ortho-(Formula presented) conversion, furthermore, couples UCN to an energy bath of excited rotational states without mediating phonons. This anomalous upscattering mechanism restricts the UCN lifetime to 4.6 msec in a normal-(Formula presented) solid with 33% para content.

Original languageEnglish (US)
Pages (from-to)R3581-R3583
JournalPhysical Review B - Condensed Matter and Materials Physics
Issue number6
StatePublished - 2000
Externally publishedYes

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Condensed Matter Physics


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