Spectral performance of a composite single-crystal filtered thermal neutron beam for BNCT research at University of Missouri

Parameter studies, design calculations and initial neutronic performance measurements have been completed for a new thermal neutron beamline to be used for neutron capture therapy cell and small-animal radiobiology studies at University of Missouri Research Reactor. The beamline features the use of single-crystal silicon and bismuth sections for neutron filtering and for reduction of incident gamma radiation. The calculated and measured thermal neutron fluxes produced at the irradiation location are 9.6x108 and 8.8x108 neutrons/cm2 s, respectively. Calculated and measured cadmium ratios (Au foils) are 217 and 132. These results indicate a well-thermalized neutron spectrum with sufficient thermal neutron flux for a variety of small animal BNCT studies.