SPORT: A new sub-nanosecond time-resolved instrument to study swift heavy ion-beam induced luminescence - Application to luminescence degradation of a fast plastic scintillator

摘要

We developed a new sub-nanosecond time-resolved instrument to study thedynamics of UV-visible luminescence under high stopping power heavy ionirradiation. We applied our instrument, called SPORT, on a fast plasticscintillator (BC-400) irradiated with 27-MeV Ar ions having high meanelectronic stopping power of 2.6 MeV/\mu m. As a consequence of increasingpermanent radiation damages with increasing ion fluence, our investigationsreveal a degradation of scintillation intensity together with, thanks to thetime-resolved measurement, a decrease in the decay constant of thescintillator. This combination indicates that luminescence degradationprocesses by both dynamic and static quenching, the latter mechanism beingpredominant. Under such high density excitation, the scintillationdeterioration of BC-400 is significantly enhanced compared to that observed inprevious investigations, mainly performed using light ions. The observednon-linear behaviour implies that the dose at which luminescence startsdeteriorating is not independent on particles' stopping power, thusillustrating that the radiation hardness of plastic scintillators can bestrongly weakened under high excitation density in heavy ion environments.