Characterization of neutron spectrum at the neutron radiography of RSG-GAS reactor using a passive single-cylindrical neutron spectrometer

Neutron spectrum characterization of RSG-GAS neutron radiography was carried out using a single-moderatorbased neutron spectrometer with a passive type Au and In activation foils neutron detector. The neutron spectrum was obtained using Unfolding Maxed-Gravel (UMG) technique based on the activity of 198Au and 116mIn after irradiation. The neutron spectrum obtained was then compared with the simulation results using the MCNPX 2.7 program. Neutron spectrum measurements using In foil provide flux values that are closer to the simulation results, there is a difference with the simulation of 25 %. The total neutron flux is (6.65 +/- 0.08) x 106 n/cm2 center dot s with thermal neutron of 83 %. The results of neutron spectrum characterization using measurements and simulations show that the RSG-GAS radiography neutron beam has a spectrum dominated by thermal neutrons with a flux of the order of 106 n/cm2 center dot s so it is very suitable as a thermal radiography neutron facility.