Preparation and luminescence properties of ZnO:Ga - polystyrene composite scintillator.

ABSTRACT

Highly luminescent ZnOGa-polystyrene composite (ZnOGa-PS) with ultrafast subnanosecond decay was prepared by homogeneous embedding the ZnOGa scintillating powder into the scintillating organic matrix. The powder was prepared by photo-induced precipitation with subsequent calcination in air and Ar/H2 atmospheres. The composite was subsequently prepared by mixing the ZnOGa powder into the polystyrene (10 wt% fraction of ZnOGa) and press compacted to the 1 mm thick pellet. Luminescent spectral and kinetic characteristics of ZnOGa were preserved. Radioluminescence spectra corresponded purely to the ZnOGa scintillating phase and emission of polystyrene at 300-350 nm was absent. These features suggest the presence of non-radiative energy transfer from polystyrene host towards the ZnOGa scintillating phase which is confirmed by the measurement of X-ray excited scintillation decay with picosecond time resolution. It shows an ultrafast rise time below the time resolution of the experiment (18 ps) and a single-exponential decay with the decay time around 500 ps.