Search for luminescent materials under 14 MeV neutron irradiation

A radiation detection system utilizing radiation-resistant optical fibers and luminescent materials will have several advantages, such as compactness and robustness, and can be a strong candidate for diagnostics of fusion neutrons. Luminescent materials - important components of an optical system - that exhibit luminescence under fast neutron irradiation were studied. Commercially available luminescent materials, such as ZnS:Ag, ZnS:Cu, SrAl₂O₄:Eu²⁺, Dy³⁺, and Sr₄Al₁₄O₂₅:Eu²⁺, Dy³⁺ exhibit luminescence under 14 MeV neutron irradiation. The materials excluding ZnS:Ag showed radiation resistance for a fast neutron fluence of up to 10¹⁴ n/cm². The luminescence characteristics of Sr₄Al₁₄O₂₅:Eu²⁺, Dy³⁺ that have three apparent peaks were also examined under proton irradiation. The compounds exhibited the same luminescence peaks under fast neutron irradiation, which can be attributed to their dopants, namely, Dy³⁺ and Eu²⁺, and the intensity ratio of Eu²⁺ to Dy³⁺ showed dependence on incident energy and radiation.