Neutron and gamma measurement with water phantom for boron neutron capture therapy (BNCT) reactor TRIGA PUSPATI

Abstract

ABSTRACT

Thermal neutron beam from thermal column was selected for a Boron Neutron Capture Therapy (BNCT) system utilising the Malaysian TRIGA MARK II reactor. Determination of shielding materials for fast and epithermal neutron was conducted. The materials selected were polyethylene, paraffin and water. For gamma-ray shielding, lead was used. The objective of this paper is to present the simulation and verification of an optimal design of BNCT collimation at a beam line viewing the thermal column. A collimator was made from polyethylene pipe with 8 cm of diameter filled with paraffin. An experiment with water phantom was conducted to simulate the human biological conditions. Gamma dose rate was 30.92 mSvhr^-1 at 0.0 cm depth and increasing up to 174.56 mSvhr^-1 at 16.5 cm depth. Neutron flux was 5.00E+06 ncm^-2s at 0.0 cm depth and 3.00E+07 ncm^-2s at the depth of 0.8 cm and then decreased to 1.00E+06 ncm^-2s at the depth of 8.1 cm.

Abstrak

Alur neutron terma dari turus terma telah dipilih untuk sistem Boron Neutron Capture Therapy (BNCT) menggunakan Malaysia TRIGA MARK II reaktor. Penentuan bahan perisaian untuk neutron epiterma dan cepat telah dibuat. Bahan yang dipilih adalah polietilena, parafin dan air. Untuk perisaian sinar gama, bahan plumbum telah digunakan. Objektif kertas ini adalah untuk bentang simulasi dan pengesahan satu reka bentuk optimum pengkolimatan BNCT di alur laluan turus terma. Satu pengkolimat telah dibuat dari paip polietilena dengan garis pusat 8 cm diisi dengan parafin. Satu ujian dengan fantom air dijalankan untuk mensimulasikan keadaan biologi manusia. Kadar dos gama ialah 30.92 mSvhr-1 di 0.0 cm kedalaman dan menambahkan sehingga 174.56 mSvhr-1 di 16.5 cm kedalaman. Fluks neutron ialah 5.00E+06 ncm-2s di 0.0 cm kedalaman dan 3.00E+07 ncm-2s di kedalaman 0.8 cm dan kemudian mengurangkan kepada 1.00E+06 ncm-2s pada kedalaman 8.1 cm.