THE TESTING OF EPITHERMAL NEUTRON BEAMS PRODUCED BY THE DOUBLE LAYER BEAM SHAPING ASSEMBLY (DLSBA) ON A WATER PHANTOM USING PARTICLE HEAVY ION TRANSPORT SYSTEM (PHITS)

Abstract

Design of double layer Beam Shaping Assembly (DLBSA) has been conducted. A Double Layer Beam Shaping Assembly (DLBSA) is designed to produce epithermal neutrons for BNCT purposes. The model of DLBSA was designed using the Particle and Heavy Ion Transport System (PHITS) in form of a double layer. The each component of the DLBSA, consisting of moderator, reflector, collimator, and filter were made of two materials. The DLBSA design produced the neutron beam with epithermal neutron flux values of 1.29 ´  10⁹ n / (cm².s), the ratio of epithermal neutron flux to thermal neutron flux and fast neutron flux 705 and 56, and the dose rate ratio fast neutron absorption and gamma dose ( of epithermal neutron flux are 1.51 ´  10^-13 Gy.cm² and 0.25 ´  10^-13 Gy.cm², respectively. The testing of epithermal neutron beams produced by the DLBSA and irradiated on a water phantom shows that epithermal neutron beams transform into thermal neutron upon entering the phantom. The thermal neutron can penetrate the phantom up to 2-8 cm deep. Therefore, the epithermal neutron beams produced by the DLSBA can be utilized for Boron Neutron Capture Therapy (BNCT) therapies of deeper located cancers.