The Dose Comparison between the Thor and the HFR Epithermal Neutron Beams

This study is a part of the beam comparison campaign, inter-center dose comparison, between boron neutron capture therapy facilities at the Tsing Hua Open-pool Reactor and the High Flux Reactor. The clinical information exchange can improve the dosimetry uncertainty for medical physics in a mixed field. The method of paired Mg(Ar) and TE(TE) ionization chambers was used to determine the gamma ray and neutron dose rates. Furthermore, activation foils, including gold, copper, and manganese, were employed to estimate the thermal and epithermal neutron fluxes. Measurements were performed free in air and also in a PMMA phantom. All the chambers were calibrated using a 60Co primary standard source at the Institute of Nuclear Energy Research, Taiwan. Spectrum dependent neutron sensitivity of TE(TE) chamber is one of the important parameters to evaluate dose components. The requested neutron spectra were calculated by the Monte Carlo code MCNP. The measured thermal neutron fluxes, gamma ray and neutron dose rates of the THOR beam in the phantom were 2.6, 2.2, and 2.1 times of the HFR beam at 2.5-cm depth, respectively. The higher thermal neutron flux and neutron and gamma-ray dose rates are due to the higher epithermal neutron beam intensity of the THOR.

LIN Yi-Chun;  ROCA Antoaneta;  LIU Yuan-Hao;  TSAI Pi-En;  NIEVAART Victor Alexander;  LIU Hong-Ming;  MOSS Raymond;  WEN-TSAE Chou;  JIANG Shiang-Huei; 

2010-12-13

PERGAMON-ELSEVIER SCIENCE LTD

JRC52766

1350-4487,   

www.elsevier.com/locate/radmeas,    https://publications.jrc.ec.europa.eu/repository/handle/JRC52766,   

10.1016/j.radmeas.2010.06.061,