Development of a table-top NRTA system using a 252Cf neutron source (1)Project overview and initial results

To advance techniques for nuclear material measurements in the fields of nuclear nonproliferation and nuclear security, we have developed a table-top Neutron Resonance Transmission Analysis (NRTA) system utilizing a 252Cf neutron source. From the viewpoint of detection of nuclear materials, the system design, including the neutron source and collimators, was optimized through Monte Carlo simulations. Based on these simulations, the neutron source and collimators were designed and constructed, where the neutron source utilized a high-density polyethylene block and lead shielding, and the collimators were made of polyethylene containing B2O3. The core components of the developed table-top NRTA system were used to measure a simulated sample of an indium plate with a resonance energy similar to that of nuclear materials. Neutron Time-of-Flight (TOF) spectra were obtained by separating neutron signals from gamma- ray signal via pulse shape discrimination. The TOF spectra revealed resonance dips corresponding to indium nuclei. These results demonstrate that the table-top NRTA system is effective for detecting nuclear materials.