Pulse height analysis and pulse shape discrimination of pure LaCl3 scintillation crystal across a broad neutron energy range

초록

A pure LaCl3 crystal scintillation detector has been developed and shows strong potential for fast neutron detection, particularly via the Cl-35(n,p)S-35 and Cl-35(n,alpha)P-32 reactions. These reaction channels make it a promising candidate for neutron spectroscopy applications in nuclear fusion research. In this study, a comprehensive characterization of the pure LaCl3 scintillation detector was performed in a mixed neutron and gamma-ray radiation field. Pulse height analysis and neutron-gamma pulse shape discrimination were systematically evaluated over a wide neutron energy range, from approximately 2.46 MeV to 16.89 MeV, using both a 252Cf spontaneous fission source and a mono-energetic neutron beam at the Fast Neutron Laboratory, Tohoku University. The results reveal a clear separation between neutron-and gamma-induced signals, with figure-of-merit values exceeding 1.18 at specific energies, demonstrating the detector's excellent pulse shape discrimination performance. The pulse height response associated with charge generation in the pure LaCl3 scintillation crystal was systematically characterized. Energy calibration and linearity for neutron energies up to 5.61 MeV were verified through the peak corresponding to the Cl-35(n,p)S-35 ground-state reaction. These findings confirm that pure LaCl3 scintillators exhibit excellent neutron-y discrimination, enabled by differences in the pulse height and decay time characteristics of the induced signals, making them well-suited for high-resolution neutron spectroscopy in mixed radiation fields typical of magnetic confinement fusion environments.

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