Shallow traps and radiative recombination processes inLu3Al5O12:Cesingle crystal scintillator

Abstract

Thermally stimulated luminescence (TSL) glow curves and emission spectra were studied in undoped and Ce-doped ${\mathrm{Lu}}_{3}{\mathrm{Al}}_{5}{\mathrm{O}}_{12}$ single crystals by wavelength resolved TSL measurements in the $10\char21{}310\phantom{\rule{0.3em}{0ex}}\mathrm{K}$ temperature range. Isothermal phosphorescence measurements in the $10\char21{}100\phantom{\rule{0.3em}{0ex}}\mathrm{K}$ range were also performed, which point to the existence of a tunneling-driven radiative recombination process. These processes can explain the presence and time-dependence of the submicrosecond slow decay component in the scintillation decay. Electron paramagnetic resonance experiments suggest the presence of ${\mathrm{Lu}}_{\mathrm{Al}}$ defects in the vicinity of ${\mathrm{Ce}}^{3+}$ ions, which are the most probable electron and hole traps participating in the tunneling-driven radiative recombination process.