Search for the Radiative Decay Mode of the Neutron

B. M. Fisher, F. E. Wietfeldt, Tulane University

  1. S. Dewey, T. R. Gentile, J. S. Nico, A. K. Thompson, NIST Physics Laboratory— Neutron Interactions and Dosimetry Group (846.03)
E. J. Beise, K. Kiriluk, University of Maryland

J. Byrne, University of Sussex


Beta-decay of the neutron into a proton, electron, and antineutrino is occasionally accompanied by the emission of a photon. Despite decades of detailed experimental studies of neutron beta-decay, this rare branch of a fundamental weak decay has never been measured, while it has been extensively investigated in more exotic systems. An experiment to study the radiative beta-decay of the neutron is currently being developed for the NG6 fundamental physics beam line at the NIST Center for Neutron Research. The experiment will make use of the existing apparatus for the NIST Penning-trap lifetime experiment, which can provide substantial background reduction by providing an electron-proton coincidence trigger. Tests and design of a detector for gamma rays in the 100 keV range are under development. The need for a large solid-angle gamma ray detector that can operate in a strong magnetic field and at low temperature has led us to consider scintillating crystals in conjunction with avalanche photodiodes. The apparatus has been installed at the the NG6 beam line, and tests have begun. We hope to have the final photon detector array installed and the entire apparatus taking data by Spring, 2004.

Presenting Author's information

Name : Brian M. Fisher
Division : 846.03
Laboratory : Physics
Room and Building address : 235 B181
Mail Stop : 8461
Telephone : (301) 975-5573
FAX : (301) 926-1604
email :
Sigma Xi member? : No.
Choose a category that best describes your poster: Physics