Abstract
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 language | English (US) |
|---|---|
| Pages (from-to) | R3581-R3583 |
| Journal | Physical Review B - Condensed Matter and Materials Physics |
| Volume | 62 |
| Issue number | 6 |
| DOIs | |
| State | Published - 2000 |
| Externally published | Yes |
ASJC Scopus subject areas
- Electronic, Optical and Magnetic Materials
- Condensed Matter Physics