The angular and spatial distributions of the thermal neutron source description of the THOR BNCT beam

This paper presents a way to determine the angular and spatial distributions of the thermal neutron source strength of a boron neutron capture therapy (BNCT) beam. The experiments applied 1) the indirect neutron radiography, 2) the cadmium difference method, and 3) the instrumental neutron activation analysis. The measured data were processed by the spectrum deconvolution technique to resolve into a proper set of angular and spatial distributions. This paper took the epithermal neutron beam of the BNCT facility at the Tsing Hua Open-pool Reactor as an example.