Ultracold neutron upscattering rates in a molecular deuterium crystal
نویسندگان
چکیده
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-D2 ~with even rotational quantum number J! and para-D2 ~with odd J! exhibit significantly different UCN-phonon annihilation cross sections. Parato ortho-D2 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-D2 solid with 33% para content.
منابع مشابه
An apparatus to control and monitor the para-D2 concentration in a solid deuterium, superthermal source of ultra-cold neutrons
In a recent investigation of solid D2 as a UCN source[1], it was surmised that the yield of UCN is correlated with the spin states of the deuterium molecules. Subsequently, detailed neutron scattering calculations and measurements of the UCN lifetime in mixtures of paraand ortho-deuterium quantitatively verified this conjecture.[2,3,4,5,6] The work we report here was motivated by our attempt to...
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