Demonstration of Shape Analysis of Neutron Resonance Transmission Spectrum Measured with a Laser-driven Neutron Source

Laser-driven neutron sources (LDNSs) can generate strong short-pulse neutron beams, which are valuable for scientific studies and engineering applications. Neutron resonance transmission analysis (NRTA) is a nondestructive assay method for determining the areal density of each nuclide in a material sample using pulsed thermal and epithermal neutrons. An experiment demonstrating resonance-transition-spectrum measurement was conducted using an LDNS driven by the Laser for Fast Ignition Experiment at the Institute of Laser Engineering, Osaka University. A 6Li glass scintillation neutron detector with a gating circuit was placed 3.6 m from the LDNS. The output waveforms from the neutron detector were recorded and analyzed offline using the counting method. A resonance spectrum was extracted from only the data of three laser shots using a 115In and 109Ag plate sample. A simulated spectrum reproduced the experimental spectrum shapes. Shape analysis of the obtained spectrum was performed, and the fitting results reproduced the experimental parameters. These results indicate the applicability of an LDNS to NRTA for nondestructive material analysis.