Preparation and luminescence properties of ZnO:Ga – polystyrene composite scintillator

Abstract

Highly luminescent ZnO:Ga-polystyrene composite (ZnO:Ga-PS) with ultrafast subnanosecond decay was prepared by homogeneous embedding the ZnO:Ga 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 ZnO:Ga powder into the polystyrene (10 wt% fraction of ZnO:Ga) and press compacted to the 1 mm thick pellet. Luminescent spectral and kinetic characteristics of ZnO:Ga were preserved. Radioluminescence spectra corresponded purely to the ZnO:Ga 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 ZnO:Ga 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.

Garnet Scintillators of Superior Timing Characteristics: Material, Engineering by Liquid Phase Epitaxy

“…In the detection part a quartz collection lens, Thorlabs FB550–40 (550 nm/40 nm FWHM) dielectric bandpass filter, and a Hamamatsu R7056 fast PMT operated in the direct current mode were used to detect scintillation light. The instrumental response function was obtained by measurement of spectrally unresolved scintillation decay of superfast Ga‐doped ZnO powder (scintillation response below 1 ns) under the same experimental conditions.…”

Needs, Trends, and Advances in Inorganic Scintillators

“…purity and doping, such as ZnO:Ga, where defect emission is absent after an appropriate reduction annealing [124]. Exciton confinement effects may also benefit the fast timing issues.…”

“…Stabilization of the surface of core should bring substantial limitation of trapping states with huge benefit for scintillation efficiency and speed of the response. Furthermore, embedding of Q-dots of direct gap semiconductors into a suitable transparent host can give rise to bulk scintillators with limited reabsorption and superfast scintillation response [124]. Note that radiation hardness has been improved using core-shell architectures [128].…”

Transparent glass ceramics containing Lu6O5F8:Tb3+ nano‐crystals: Enhanced photoluminescence and X‐ray excited luminescence

“…On account of the much demand for novel scintillating materials with large‐volume, low‐cost and easy‐fabrication, great attention recently has been attracted by alternative scintillating materials, such as transparent glasses, ceramics and nanocomposite materials …”