Conceptual Design of Collimator at Boron Neutron Capture Therapy Facility with 30 MeV Cyclotron and Target 9Be as Neutron Generator Using Monte Carlo N-Particle Extended Simulator

Abstract

The optimization of collimator has been studied which resulted epithermal neutron beam for Boron Neutron Capture Therapy (BNCT) using Monte Carlo N Particle Extended (MCNPX). Cyclotron 30 MeV and 9 Be target is used as a neutron generator. The design criteria were based on recommendation from IAEA. Mcnpx calculations indicated by using 25 cm and 40 cm thickness of PbF2 as reflector and back reflector, 15 cm thickness of TiF3 as first moderator, 35 cm thickness of AlF3 as second moderator, 25 cm thickness of 60 Ni as neutron filter, 2 cm thickness of Bi as gamma filter, and aperture with 20 cm of diameter size, an epithermal ne utron beam with an intensity 1.21 × 10 9 n.cm -2 .s -1 , fast neutron and gamma doses per epithermal neutron of 7.04 × 10 -13 Gy.cm 2 .n -1 and 1.61 × 10 -13 Gy.cm 2 .n -1 , minimum thermal neutron per epithermal neutron ratio of 0.043, and maximum directionality of 0.58, respectively could be produced. The results have not passed all the IAEA's criteria in fast neutron component and directionality.

Beam Shaping Assembly Optimization for Boron Neutron Capture Therapy Facility Based on Cyclotron 30 MeV as Neutron Source

“…The previous BSA design of Isyan et al (2017) is shown in Figure 1. In this research we focus on optimizing the BSA design especially in two parameters; those are the ratio of gamma dose rate and epithermal neutron flux, and the ratio of particle current and total flux.…”

“…PbF2 is chosen as a reflector based on Isyan's design (Isyan et al 2017). It performs well in reflecting the neutron beam.…”

“…Accordingly, to reach all of the parameters written above, it needs a BSA as the collimator to filter and moderate fast neutron produced by the reaction of beryllium and high energy proton. A BSA collimator has been designed by Isyan et al (2017) to produce epithermal neutron for BNCT based on cyclotron 30 MeV using a beryllium target. The value of IAEA's parameters and the value of Isyan's BSA design is shown in Table 1 (Isyan et al 2017) The two shaded columns show the parameters which have not already met the requirements of IAEA.…”

“…A BSA collimator has been designed by Isyan et al (2017) to produce epithermal neutron for BNCT based on cyclotron 30 MeV using a beryllium target. The value of IAEA's parameters and the value of Isyan's BSA design is shown in Table 1 (Isyan et al 2017) The two shaded columns show the parameters which have not already met the requirements of IAEA. Therefore, Isyan et al (2017).…”

“…The value of IAEA's parameters and the value of Isyan's BSA design is shown in Table 1 (Isyan et al 2017) The two shaded columns show the parameters which have not already met the requirements of IAEA. Therefore, Isyan et al (2017).…”