Aberration in the Attenuation of the Activity of Threshold Detectors Measured in the Pool of the Swimming-Pool Reactor SAPHIR

摘要

Fast neutron flux attenuation as function of the distance from the reactor core center was measured in the pool water of the SAPHIR swimming pool reactor by means of activated detectors. After about 80 cm, the curve of the Rhodium and Indium detectors based on the activation of the isomeric level, becomes flatter, while the Phosphorus detectors based on the (n,p) reaction behave as would be predicted. Comparative calculations demonstrated that Rhodium and Indium were activated by a nuclear fluorescence reaction (gamma,gamma), which predominates after an attenuation of the neutron flux of about 5 decades. (ERA citation 12:013510)