Abstract A new neutron imaging (NI) facility based on a 30-MeV cyclotron is currently being developed at the National Research and Innovation Agency (BRIN) of Indonesia. This study aims to simulate an optimal neutron delivery system for NI using Monte Carlo method by Particle and Heavy Ion Transport Code System (PHITS) software. The cyclotron accelerates 30 μA protons up to 30 MeV which are directed onto a beryllium target to produce neutrons. After being moderated, neutrons are ejected using a one-meter-long radial beam tube. Our investigation centred on the influence of different reflector and filter materials on the neutron flux. At the start of the beam tube, the overall neutron flux is 3.74 × 10 6 neutrons.cm −2 .s −1 , of which 42.7% are thermal. Our findings suggest that an aluminium reflector coupled with a 5-cm thick graphite filter is the most effective configuration for minimizing neutron flux loss. This configuration delivers 2.17×10 4 neutrons.cm −2 .s −1 , of which 69.02% are thermal neutrons. This number is comparable to other thermal neutron imaging facilities worldwide.
Prastowo et al. (Tue,) studied this question.