Neutron intensity monitor with activation foil for p-Li neutron source for BNCT - Feasibility test of the concept

Proton-lithium (p-Li) reaction is being examined worldwide as a candidate nuclear production reaction for accelerator based neutron source (ABNS) for BNCT. In this reaction, the emitted neutron energy is not so high, below 1 MeV, and especially in backward angles the energy is as low as about 100 key. The intensity measurement was thus known to be difficult so far. In the present study, a simple method was investigated to monitor the absolute neutron intensity of the p-Li neutron source by employing the foil activation method based on isomer production reactions in order to cover around several hundreds keV. As a result of numerical examination, it was found that Ag-107, In-115 and Os-189 would be feasible. Their features found out are summarized as follows: Ag-107: The most convenient foil, since the half life is short. In-115: The accuracy is the best at 0 degrees, though it cannot be used for backward angles. And Os-189: Suitable nuclide which can be used in backward angles, though the gamma-ray energy is a little too low. These would be used for p-Li source monitoring depending on measuring purposes in real BNCT scenes. (C) 2015 Elsevier Ltd. All rights reserved.