Characteristics of BGO scintillator for use in neutron capture cross section measurements

A detector assembly of BGO scintillators has been set up for use in neutron capture cross section measurements as a total absorption detector of prompt capture gamma rays. This report describes a few experimental studies of the essential characteristics of the BGO detector assembly. The assembly has a scintillator volume of 1.5 l, and the response to the gamma-ray cascade of neutron capture by Au has been found to be nearly equivalent to that of a typical organic-liquid scintillator tank. The efficiency for the 478 keV gamma ray of the 10B(n, αγ) reaction has been determined for the purpose of using the reaction as a neutron flux monitor impinging on a capture sample. The sensitivity to neutrons scattered with a capture sample has been measured between the thermal region and 60 keV. The sensitivity is comparatively high and the employment of a 6LiF shield has been shown to be effective for the reduction of the sensitivity in the eV region. (orig.)