Recent Progress of Large Size BaF2:Y Crystals for Future HEP Experiments

Because of its ultrafast light with sub-ns decay time and the suppressed slow scintillation light yttrium doped barium fluoride (BaF
2
:Y) crystals attract a broad interest in the community pursuing ultrafast detector technology. BaF
2
:Y crystals of large size were grown for the proposed Mu2e-II calorimeter. Their scintillation performance, such as transmittance, light output, and fast/slow ratio, was characterized. Gamma-ray induced readout noise was found to be dominated by the slow scintillation component in BaF
2
crystals.