Beam optimization for boron neutron capture theraphy at thermal column of TRIGA Mark-II research reactor

Abstract

The thermal column at TRIGA PUSPATI research reactor has an ability to produce thermal neutron. However, the optimization on the thermal neutron flux produced should be performed in order to gain a sufficient thermal neutron for boron neutron capture therapy purpose. Thus, the objective of this study is to optimize the thermal neutron flux by designing the collimator with different materials at the thermal column. In order to fulfil the requirement, set by the IAEA standard, the collimator was designed using Monte Carlo N-Particle simulation. Initially, the measurement of the thermal neutron flux was conducted along the thermal column at 250 kW. The thermal column was divided into 3 phases (Phase 1, Phase 2 and Phase 3) so that an accurate measurement can be obtained by using gold foil activation method and thermoluminescent dosimeter detector. This value was used as a benchmark for the neutron flux produced from the thermal column. The collimator was designed using different types of materials and their characteristic towards gamma and neutron flux was investigated. The results demonstrated that the final thermal neutron flux produced was significantly depends on the shielding thickness, aperture size and collimator conditions (uncovered or fully covered). The collimator design using thickness shielding of 5+10 cm of lead, aperture size of 3 cm and operated using uncovered condition has produced the optimum thermal neutron flux. The sufficient amount of thermal neutron flux of 3.28 x 108 neutron.cm-2s-1 at 250 kW of TRIGA PUSPATI research reactor power produced from the designated collimator was achieved.