Characterization of ultracold neutron production in thin solid deuterium films at the PSI Ultracold Neutron source
Journal
Physical Review C
Journal Volume
107
Journal Issue
3
Start Page
035501
ISSN
2469-9985
2469-9993
Date Issued
2023-03-07
Author(s)
Abstract
We determined the ultracold neutron (UCN) production rate by superthermal conversion in the solid deuterium (sD2) moderator of the UCN source at the Paul Scherrer Institute (PSI). In particular, we considered low amounts of less than 20 mol of D2, deposited on the cooled moderator vessel surfaces in thin films of a few mm in thickness. We measured the isotopic (cHD<0.2%) and isomeric (cpara≤2.7%) purity of the deuterium to conclude that absorption and up-scattering at 5 K have a negligible effect on the UCN yield from the thin films. We compared the calculated UCN yield based on the previously measured thermal neutron flux from the heavy water thermal moderator with measurements of the UCN count rates at the beamports. We confirmed our results and thus demonstrated an absolute characterization of the UCN production and transport in the source by simulations.
SDGs
Publisher
American Physical Society (APS)
Type
journal article