Ultracold Neutron Production by the Phonon Excitation in Superfluid ⁴He at Temperatures below 1 K

Article type: Research Article

Authors: Morishima, Nobuhiro | Sakakibara, Masahiko

Affiliations: Department of Nuclear Engineering, Kyoto University, Yoshida, Sakyo-ku, Kyoto 606-8501, Japan

Note: [] Corresponding author. Tel./Fax: + + 81 75-753-5836, e-mail: [email protected]

Abstract: Production of ultracold neutrons in superfluid 4He is discussed in terms of downscattering of an 1 meV neutron through phonon creation at temperatures below 1 K. By the use of a cross-section model developed for neutron scattering in liquid 4He, a set of scattering cross sections such as double-differential, angular-distributional and total ones is calculated. It is shown that the phonon–roton(quasipartic1e) excitation plays an essential role in marked production and storage of ultracold neutrons, especially for temperatures down to 0.1 K.

Keywords: Ultracold neutron, Cold neutron, Liquid helium, Superfluid, Neutron source

DOI: 10.1080/10238160008206328

Journal: Journal of Neutron Research, vol. 8, no. 4, pp. 233-243, 2000