Dependence of cross-relaxation on temperature and concentration from the 1D2 level of Pr3+ in YPO4

► We present data on the decay of the 1D2 level of Pr in YPO4 from 30-300 K. ► We determine the 1D2 cross-relaxation rate throughout that temperature range. ► Fits to the data indicate diffusion among the Pr ions is negligible. ► Radiative efficiencies of the 1D2 level are determined.