Synthesis of bulk-size transparent gadolinium oxide-polymer nanocomposites for gamma ray spectroscopy.

Heavy element loaded polymer composites have long been proposed to detect high energy X- and γ-rays upon scintillation. The previously reported bulk composite scintillators have achieved limited success because of the diminished light output resulting from fluorescence quenching and opacity. We demonstrate the synthesis of a transparent nanocomposite comprising gadolinium oxide nanocrystals uniformly dispersed in bulk-size samples at a high loading content. The strategy to avoid luminescence quenching and opacity in the nanocomposite was successfully deployed, which led to the radioluminescence light yield of up to 27 000/MeV, about twice as much as standard commercial plastic scintillators. Nanocomposites monoliths (14 mm diameter by 3 mm thickness) with 31 wt% loading of nanocrystals generated a photoelectric peak for Cs-137 gamma (662 keV) with 11.4% energy resolution.