Development of anticoincidence detector specializing in small-angle Compton scattering gamma rays for boron neutron capture therapy.

A novel anticoincidence detector is proposed for the measurement of 478 keV gamma radiation for evaluation of boron neutron capture therapy. The Compton continuum around the target photopeak position is effectively suppressed by measuring only the Compton gamma rays scattered at small angles from the primary detector. A numerical evaluation using Monte Carlo simulations estimated an 80% reduction in counts, and the developed prototype detector showed 4% suppression of the Compton continuum of cobalt-60 gamma rays.

Development of compact sensor with CdS photoresistor for high gamma-ray field monitoring.

A compact gamma-ray sensor composed of a cadmium sulfide (CdS) photoresistor and a small-sized cesium iodine doped thallium scintillator is introduced for intense gamma-ray monitoring. The sensor exhibits radiation-resistant ability and a linear output response over a wide dose range. The dose rate at several conditions was measured for confirmation of feasibility.