A Solid Ortho-deuterium Superthermal Ultra-cold Neutron Source
Abstract
Although solid ortho-deuterium is well known as one of the best materials from which to construct a superthermal UCN source, there are a number of important technical issues which arise from attempting to utilize this material. Perhaps the most important is the existence of para-D2 contaminants to the crystal. UCN scatter off those meta-stable para molecules and inherit the excessive energy from the nontrivial rotational configuration. This upscattering mechanism greatly shorten the UCN resident time in the solid source. In addition, other contaminants can exist(such as HD, H_2...), and transport properties through the D2 ice can be complicated as well. We attempt to deal with these problems by first converting as much of the para-D2 to ortho-D2 as possible, and then performing precise measurements of the para-D2 concentrations using rotational Raman spectrometry on D2 gas extracted from the source, and using the same spectra to monitor the concentration of HD, H_2. Details of the physics of the UCN production in solid D2 and our experimental approach to the technical difficulties noted above will be presented.
- Publication:
-
APS April Meeting Abstracts
- Pub Date:
- April 2001
- Bibcode:
- 2001APS..APRQ13009L