Two-step sintering of Gd_03Lu_16Eu_01O_3 transparent ceramic scintillator

Transparent ceramic scintillators with the composition Gd0.3Lu1.6Eu0.1O3 (GLO:Eu) have been prepared by different sintering profiles: a traditional profile consisting of a slow ramp followed by a dwell, and a two-step profile consisting of a fast ramp and short dwell followed by a long dwell at a lower temperature. A subsequent Hot Isostatic Press (HIP) step was used to achieve full density and transparency. Two-step sintering allowed full transparency to be achieved after HIPing at 1525°C, while traditionally sintered samples required 1850°C in the HIP to achieve high transparency indicating that two-step sintering is successful in maintaining a small grain size and therefore allowing densification to be decoupled from grain growth during the low temperature HIP step. HIPing at elevated temperatures between 1525 and 1850°C resulted in rapid grain growth from sub-micron to ~300 µm grains. Radioluminescence spectra show negligible difference between samples with sub-micron grain size and those with 300 µm grains.