Conceptual design of prompt gamma neutron activation analysis facility at Tehran Research Reactor for BNCT application

摘要

Since Tehran Research Reactor (TRR) is the only available neutron source, which can be used for Boron Neutron Capture Therapy (BNCT) in Iran, it is essential to provide an appropriate analysis system at TRR in order to determine B-10 concentration in sample tissue or blood. Based on the advantages, Prompt Gamma Neutron Activation Analysis (PGNAA) facility has been selected. Irradiation channels in TRR have been studied using Monte Carlo MCNPX2.6 code and evaluated to provide the appropriate neutron beam for PGNAA. Based on the results of neutron intensity and spectrum, F-beam tube is considered to be the most favorable for PGNAA, and has therefore been selected for further investigation and MCNP simulation. Bismuth blocks for decreasing gamma radiation, and Fluental (TM) as a filter for fast neutron have been used in F-beam tube. The convergent collimator with iron and polyethylene has been considered to shape the neutron beam and to reduce the neutron and gamma-ray fluxes at the position of the HPGe gamma-ray detector. The sensitivity of the designed system is determined, from MCNP simulation, to be 7.35 cps/mu g.