Mixed-field dosimetry measurement of a target assembly for an accelerator-based neutron source for boron neutron capture therapy

The objective of this work was to measure the neutron and gamma-ray absorbed dose components for a target assembly for an Accelerator-Based Neutron Source (ABNS) for Boron Neutron Capture Therapy (BNCT), and to compare these measurements with MCNP calculations in order to verify the calculations of the in-air neutron and gamma-ray absorbed dose components. The measurements were made using the paired ionization chamber technique. The measured neutron and gamma-ray specific absorbed dose components agreed with calculations within experimental errors, which were approximately 10%. The measured gamma-ray specific absorbed dose rate of 140 cGy s ^-1 A ^-1 ±12% is consistent with reported yields of 478 keV gamma rays due to the ⁷Li(p, p') ⁷Li ^* reaction. This specific gamma absorbed dose rate is significant and should not be neglected in moderator assembly design.