Luminescent properties of Cr-doped (Gd , Y1−)3Al5O12 infra-red scintillator crystals

Abstract Cr-doped (Gd X Y 1 − X ) 3 Al 5 O 12 ( X = 0, 0.25, 0.50) crystals prepared by the micro-pulling down method were investigated to develop a infra-red scintillator for implantable patient dosimeter in radiation therapy. In order to evaluate their optical and scintillation performance, the following properties were measured: (i) transmittance between ultra-violet and near-infra red region, (ii) photoluminescence spectra under Xe-lamp excitation, and (iii) X-ray excited radio-luminescence spectra. Cr:Y 3 Al 5 O 12 and Cr:(Gd 0.25 Y 0.75 ) 3 Al 5 O 12 crystals showed increased transmittance of 80%, while Cr:(Gd 0.50 Y 0.50 ) 3 Al 5 O 12 had a lower transmittance of 40% due to its polycrystalline structure. In addition, all the Cr:(Gd X Y 1− X ) 3 Al 5 O 12 crystals showed sharp scintillation luminescence peaks ascribed to Cr 3+ d–d transitions. Therefore, these results suggested that Cr:Y 3 Al 5 O 12 and Cr:(Gd 0.25 Y 0.75 ) 3 Al 5 O 12 crystals can be candidate materials for the dosimeter use.