Development features of radiation-resistant materials for composite scintillators and wavelength shifting light guides

The paper discusses the possible processes of radiation-induced changes that occur during irradiation of composite scintillators containing grains of inorganic crystals, and investigates the effect of these processes on radiation resistance of composite systems. All crystalline inorganic scintillation materials contain defects, which can play the role of quenching centres. An irradiation destroys and changes not only the main material of a scintillator but such the centres as well. As a result, the luminescence intensity can grow for a while due to weakening the effect of quenching. In this case, the luminescence spectrum of a scintillator does not change its shape under various accumulated doses D because no new luminescence centres appear. A modification of the properties of the luminescence centres arising under the action of irradiation has to lead to a change in the spectral characteristics of the luminescence. Therefore, the appearance or absence of such the changes is evidence of which centres are predominantly damaged because of irradiation with given dose D. The paper as well discusses the possibilities of obtaining radiation-resistant materials for the development of wavelength shifting light guides for composite scintillators. We investigated samples based on non-luminescent transparent silicone elastomer containing p-terphenyl or 1,4-di[2-(5-phenyloxazolyl)]benzene (POPOP) molecules.