Low temperature scintillation properties of Ga2O3

Gallium oxide has recently been identified as a promising scintillator. To assess its potential as a detector material for ionizing radiation at low temperatures, we measured the luminescence and scintillation properties of an undoped Ga2O3 crystal over the 7-295K temperature range. The emission of the crystal is due to the radiative decay of self-trapped excitons and donor-acceptor pairs and peaks at a wavelength of 380nm. The scintillation light output of the undoped Ga2O3 increases with a decrease in temperature, reaching a maximum value of 19 300 +/- 2200ph/MeV at 50K. The measured luminescence kinetics has a recombination character with specific decay time (tau(0.1)) increasing from 1 to 1.8 mu s at cooling. Since radiative decay in the crystal competes with nonradiative processes, material optimization could lead to the scintillator achieving a yield of 40800ph/MeV, a figure considered to be an upper limit.