Masanori Koshimizu

Abstract Recent development of organic scintillators is reviewed from the viewpoint of materials science. Design and crystal growth of organic crystalline scintillators, use of novel solvents and solutes in liquid scintillators, and development of plastic scintillators based on novel polymer hosts or novel fluorescent molecules are introduced. Additionally, development of loaded liquid or plastic scintillators is reviewed on the basis of two approaches of loading: molecules or nanoparticles. A d

Development of organic–inorganic nanocomposite scintillators as a new class of scintillators is reviewed. Advantages and shortcomings of polymer-based organic scintillators, i.e. plastic scintillators, are described among the desired properties of scintillators. Development of scintillators by addition of organometallic compounds in the plastic scintillators as an approach to overcome the shortcomings is introduced. In comparison to this approach, nanocomposite scintillators comprising plastic s

The origin of the fast scintillation component of Ce-doped LiCaAlF6 crystal excited by gamma ray irradiation was studied with X-ray and vacuum ultraviolet (VUV) irradiation. A fast luminescence component was observed under VUV irradiation and was ascribed to luminescence at defects in the host matrix on the basis of VUV spectroscopy. No fast scintillation component was observed in the scintillation time profile under X-ray irradiation. The fast scintillation component under gamma ray irradiation

The x-ray detection capability of a scintillation detector equipped with a BaCl2 single crystal was evaluated. The scintillation decay kinetics can be expressed by a sum of two exponential decay components. The fast and slow components have lifetimes of 1.5 and 85 ns, respectively. The total light output is 5% that of YAP:Ce. A subnanosecond timing resolution was obtained. The detection efficiency of a 67.41 keV x-ray is 87% for a detector equipped with a BaCl2 crystal 6-mm thick. Thus, excellen

Scintillation characteristics of undoped BaCl2, a novel fast scintillation material, were investigated. Scintillation photons with wavelength ranging from 250–600 nm were observed with two luminescence bands at 300 and 400 nm. The scintillation time profiles consisted of two lifetime components. The shorter component had a lifetime of 1.6 ns, while the longer one had a lifetime of several tens of nanoseconds. The origin of the fast component has been attributed to self-trapped excitons, whereas

To clarify the correlation between the positron lifetime and the pore size in mesoporous materials, the positron lifetime profiles of SBA-3 were measured. SBA-3 has ordered cylindrical pores, and the pore size can be controlled using surfactant molecules of different length as templates. Thus, SBA-3 is appropriate as a model material in order to establish the correlation. The lifetime of the longest component was attributed to annihilations in the intergrain space. The lifetime of the second lon