Development of a Table-Top NRTA System: Monte Carlo Study of Collimator/Shielding for Pu Pellet Sample Measurement

The present Monte Carlo study was conducted to evaluate the efficacy of a table-top Neutron Resonance Transmission Analysis (NRTA) system for measuring small Nuclear Material (NM) samples, such as plutonium (Pu) pellets, using a compact 252 Cf spontaneous fission neutron source.Time-of-flight spectra obtained from a 2 cm cylindrical Pu pellet sample exhibited resonance dips when subjected to collimator/shielding made of polyethylene (PE) that contained 20 % of BO (BO-PE) and 50 % of LiF (LiF-PE).In contrast, the TOF spectra obtained using plain PE and air exhibited no discernible resonance dips.These results demonstrate the capability of the designed table-top NRTA system to measure small NM samples efficiently when employing suitable collimator/shielding materials.Given the results associated with BO-PE, it is planned to be used in implementing the physical table-top NRTA system.