Photoluminescence, and scintillation/thermoluminescence yields of several Ce3+ and Eu2+ activated borates

Powder samples of the borates YBO3 : Ce3+, GdBO3 : Ce3+, Li6Y(BO3)3 : Ce3+, LaB3O6 : Ce3+, GdB3O6 : Ce3+, LaMgB5O10 : Ce3+, YMgB5O10 : Ce3+, CaLaB7O13 : Ce3+, CaLaB7O13 : Eu2+, Ca4YO(BO3)3 : Ce3+ and CaYOBO3 : Eu2+ were studied. The photoluminescence properties of Ce3+ in these compounds are discussed and some of them are reported for the first time. The scintillation light yield of the orthoborates YBO3 : Ce3+, GdBO3 : Ce3+, ScBO3 : Ce3+ and YAl3B4O12 : Ce3+ is of the order of 10,000 pho/MeV. The light yield due to Ce3+ in the other borates is an order of magnitude lower. In LaB3O6 : Ce3+ and LaMgB5O10 : Ce3+ a broad emission band, attributed to self-trapped exciton (STE) emission, is observed under X-ray excitation. The STE light yield of LaB3O6 : Ce3+ (0.05%) is 8000 pho/MeV and it is quenched at higher Ce concentrations. Thermoluminescence measurements show that none of these materials has a potential to be utilized as a thermal neutron storage phosphor.