Design, construction and characterization of a new neutron beam for neutron radiography at the Tehran Research Reactor

To obtain a thermal neutron beam for neutron radiography applications, a neutron collimator has been designed and implemented at the Tehran Research Reactor (TRR). TRR is a 5 MW open pool light water moderated reactor with seven beam tubes. The neutron collimator is implemented in the E beam tube of the TRR. The design of the neutron collimator was performed using MCNPX Monte Carlo code. In this work, polycrystalline bismuth and graphite have been used as a gamma filter and an illuminator, respectively. The L/D parameter of the facility was chosen in the range of 150-250. The thermal neutron flux at the image plane can be varied from 2.26 x 10(6) to 6.5 x 10(6) n cm(-2) s(-1). Characterization of the beam was performed by ASTM standard IQI and foil activation technique to determine the quality of neutron beam. The results show that the obtained neutron beam has a good quality for neutron radiography applications. (C) 2016 Elsevier B.V. All rights reserved.