Photophysical Properties of Scintillation Systems.

Available from UMI in association with The British Library. The photophysical behaviour of a number of liquid and copolymeric systems of potential importance in the field of scintillator technology have been studied. In addition, certain technical performance parameters have been determined in the case of the plastic scintillators. Unambiguous evidence, based on transient decay studies and time-resolved spectroscopic techniques, for excimer formation in oxazole and oxadiazole species is presented. Similar photophysical investigations of a novel pyrazoline derivative scintillator reveals that, like the oxazole and oxadiazole scintillators, description of its photophysical behaviour in terms of conventional kinetic schemes is not possible. Schemes to account for these deviations are proposed. The concept of weakly boundluminescent excimeric species has been proposed, with the concomitant large spectral overlap of monomer and excimer emission, to account for the kinetic behaviour exhibited by the oxazole and oxadiazole species. In contrast, the pyrazoline derivative (PMP) does not appear to form a luminescent excimer and the existence of a 'dark complex' has been invoked to explain the observed photophysics. Scintillator series based on styrene-methylmethacrylate copolymeric host matrices of varying composition containing several scintillator solutes have been characterised in terms of their photophysical behaviour and performance as scintillators. The solutes used were the subject of photophysical studies undertaken in the liquid systems. The principal photophysical processes contributing to the overall scintillator decay profile have been identified. Their performance, both in relation to one another and to commercially available scintillators, has been assessed. An azeotropic copolymeric scintillator of vinyltoluene and methylmethacrylate doped with naphthalene has been synthesised and studied. With some synthetic modifications, the plastic scintillators synthesised could form the basis of novel commercial scintillation products.