Near-infrared luminescence of red Bi4Ge3O12 down to a temperature of 8 K

Red Bi4Ge3O12 (BGO) crystals were obtained by the vertical Bridgman method. The absorption/transmittance spectra of red BGO in the visible and near-infrared (NIR) regions were measured at room temperature. The luminescence and decay time in the NIR region were then measured down to a temperature of 8 K. A broad emission band was found at approximately 1150 nm at T<200 K, and the luminescence lifetime was measured at several hundred microseconds. Decreased temperature led to increased luminescence intensity. We report that red BGO is a promising cryogenic scintillator for experimental rare-event research.