The scintillation properties of organic-inorganic layered perovskite-type compounds were analyzed using pulsed beams having different linear energy transfers (LETs). Initially the decay was slower and then became faster at higher LETs. A possible cause of the slower decay at higher LETs is the competition between the radiative process and trapping at nonradiative sites, resulting in some excitons not being trapped at nonradiative sites at which other excitons have already been trapped at higher LETs. The faster decay at higher LETs is attributed to the interaction of excited states, such as biexciton formation or a nonradiative Auger process. In addition, the LET dependence was most pronounced for (C 6 H 5 C 2 H 4 NH 3 ) 2 PbBr 4 , whose radiative rate and luminescence quantum efficiency were the highest among the investigated compounds. This result is because the radiative process in this compound, as a major decay process, is more significantly influenced by excited state interactions at higher LETs.

Abstract:The ion beam facility at the Takasaki Advanced Radiation Research Institute, the National Institutes for Quantum and Radiological Science and Technology, consists of a cyclotron and three electrostatic accelerators, and they are dedicated to studies of materials science and bio-technology. The paper reviews this unique accelerator complex in detail from the viewpoint of its configuration, accelerator specification, typical accelerator, or irradiation technologies and ion beam applications. The institute has also irradiation facilities for electron beams and 60 Co gamma-rays and has been leading research and development of radiation chemistry for industrial applications in Japan with the facilities since its establishment. The configuration and utilization of those facilities are outlined as well.

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