Use of Threshold Activation Detectors to Obtain Neutron Kerma for Biological Irradiations

Fission and non-fission activation foils have been irradiated in the experimental room at the Armed Forces Radiobiology Research Institute (AFRRI) in Bethesda, Maryland, in order to characterize the neutron field there. The field, which is generated by neutrons from a TRIGA MARK-F reactor adjacent to the room, is used for radiobiological experiments. The neutron exposure parameter, neutron tissue kerma rate per unit reactor power, is derived from individual detector measurements and an a priori spectrum obtained from neutron transport calculations. Beginning with conventional averaging of single-detector results, the analysis proceeds to a least-squares adjustment which avoids spectrum interpolation.