Novel scintillator using ZnO-family phosphor for neutron detection

Abstract

  A neutron detection sheet composed of ZnS:Ag as scintilator and ⁶LiF as neutron converter has been conventionally used for neutron detection including imaging detector using photon counting method, because of its high luminescent rate for α ray. However, the week point of ZnS;Ag scintilator is to have the slow component of the lifetime. Thus we began to investigate other II-VI compound phosphors without the slow component of lifetime for neutron detectors using the photon counting method. In this study, Cu, In, Al and Ga impurity doped ZnO family phosphor samples without the slow component of lifetime for neutron detectors under high counting rate has been tried to fabricate using a Spark Plasma Sintering method. It was found that Ga₂O₃(30mol%)-doped ZnO (ZnO:Ga₂O₃) exhibited the highest intensity of luminescence at the wavelength of 383 nm. The intensity of the 383 nm luminescence with the lifetime of about 4 ns was comparable to that of ZnS:Ag phosphor with lifetime of about 220 ns, indicating that ZnO: Ga₂O₃ phosphor can be used as a promising phosphor material for the neutron image sensor. It was also found that the PL intensity of ZnO:Ga₂O₃ phosphor samples was not decreased by adding of B₂O₅ as (n, α) converter. It was confirmed that ZnO:Ga₂O₃/B₂O3 scintillator prepared responds to the neutron beam which is emitted by the Japan Research Reactor (JRR-3) reactor.