Photoluminescence and scintillation of LGS (La_3Ga_5SiO_(14)), LNGA (La_3Nb_(0.5)Ga_(5.3)Al_(0.2)O_(14)) and LTGA (La3Ta_(0.5)Ga_(5.3)Al_(0.2)O_(14)) single crystals

摘要

To examine scintillation response of piezoelectric crystals the ~(241)Am 5.5 MeV a-ray excited emission spectra of langasite family crystals, LGS (La_3Ga_5SiO_(14)). LNGA (La_3Nb_(0.5)Ga_(5.3)Al_(0.2)O_(14)) and LTGA (La_3Ta_(0.5)-Ga_(5.3)Al_(0.2)O_(14) were measured. Dominating emission bands were observed at 378 nm for LGS, 556 nm for LNGA and 425 nm for LTGA. X-ray excited radioluminescence intensity of these crystals was quantitatively compared with BGO standard scintillator. Photoluminescence 2D-spectra were measured as well and compared with radioluminescence ones. In LTGA also photoluminescence decays were measured for two dominant contributing emission centers. Observed emission bands within 300-360 nm and beyond 400 nm most probably belong to self-trapped or trapped excitons and lattice defects, respectively.