Coated Micro-Particle Simulations with ⁶LiF/ZnS(Ag) and ¹⁰B/ZnS(Ag) for Improved Neutron Detection Efficiency

Coated micro-particle scintillation detectors are a promising technology to improve the neutron detection by enhancing both the charged particle energy deposition in the scintillator and the optical photon propagation inside the active detection medium. The incentive is to maximize the energy deposition in the scintillator by coating the neutron converter (such as⁶LiF or ¹⁰B) and to maximize the light transport efficiency by making the relatively opaque scintillator (ZnS(Ag)) as thin as possible. In this work, coated micro-particles were modeled as concentric spheres. Single-particle simulations were performed to find the optimal radius of the neutron converters and optimal thickness of the scintillator. Multi-particle simulations were also performed to determine the optimal pitch (particle-to-particle distance) and the optimal detector thickness (the number of particle layers). ⁶LiF/ZnS(Ag) detectors are shown to perform better than ¹⁰B/ZnS(Ag) detectors in terms of neutron detection by allowing more mass of neutron converters in the active volume. However, it is also shown in the results that the ¹⁰B-based coated micro-particle detectors would be more efficient per unit mass of the neutron converter. The results obtained in this work are being used in the manufacturing processes aimed at producing initial samples of coated micro-particle detectors.