J. Phys. III France
Volume 7, Numéro 10, October 1997
Page(s) 1941 - 1954
DOI: 10.1051/jp3:1997233
J. Phys. III France 7 (1997) 1941-1954

Spectral Evolution During Ultracold Neutron Storage

A. Steyerl1, S.S. Malik1, P. Geltenbort2, S. Neumaier2, V.V. Nesvizhevskii2, M. Utsuro3 and Y. Kawabata3

1  Department of Physics, University of Rhode Island, Kingston, R.I. 02881, U.S.A.
2  Institut Laue-Langevin, F38042 Grenoble, France
3  Research Reactor Institute, Kyoto University, Osaka 590-04, Japan

(Received 9 December 1996, revised 8 July 1997, accepted 9 July 1997)

In a precision measurement of the spectrum of ultracold neutrons as it evolves during storage in a "neutron bottle" we have observed an indication of a surprising heating by $\approx$ 10 -10 eV, occurring during the initial several 100 s of storage. We have not found any simple explanation. The data are, however, consistent with unconventional ideas proposed previously by two of us.

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