Scintillation Properties of Red-emitting Li₂Hf(I, Br)₆ Scintillators for Remote Real-time Neutron and Gamma-ray Monitors to Apply into Decommissioning of Nuclear Power Plants

Abstract

  A radiation detector consisting of a scintillator and optical fiber has been proposed for the decommissioning of nuclear power plants to determine the dose rate in real-time. Inside the plant, gamma-ray and neutron emitting debris can remain, and the scintillator is required to have gamma-ray and neutron sensitivity. Moreover, red or near-infrared emission scintillators have the advantage to obtain higher sensitivity. In such demand, we have developed Li₂Hf(Br, I)₆ scintillator with an emission wavelength of around 650 nm under visible light excitation and X-ray excitation. The light outputs of this material excited by thermal neutron and 662-keV gamma-ray excitation were evaluated to be 18,000 photons/(thermal neutron) and 16,000 photons/MeV, respectively. Therefore, we found this material has a potential to apply such a real-time monitor.