Neutron-Induced Dose Enhancement in Tantalum

Local dose enhancement caused by neutron capture in tantalum devices has been predicted but not previously measured. An experiment is reported in which the dose due to conversion electrons and sub-MeV photons resulting from neutron capture in Ta is compared to the dose from high-energy photons. For measurements on a thin Ta foil using a silicon surface barrier detector and incident neutrons in the resonance region (thermal to 500 eV), the dose enhancement ratio (dose due to all secondary radiations/dose due to super-MeV photons) was found to be 4.7 ± 0.3.