La₂Hf₂O₇: Ti⁴⁺ ceramic scintillator for x-ray imaging

Transparent ceramic scintillators of La₂Hf₂O₇: Ti⁴⁺ were developed by a novel combustion synthesis method. The optical transmittance for a 1.0-mm-thick specimen is about 60% of the incident light, and the x-ray stopping power is also quiet high. The broad emission band centered at 475 nm originates from the oxide-Ti⁴⁺ charge-transfer transitions, which renders fast decay time on the order of 10 μs. The highest relative light output has reached about 1.5 times that of Bi₄Ge₃O₁₂ (BGO) single crystal when excited by 120 kV x-rays.