Lead based halide crystals for the HHCAL detector concept

Good UV transmittance and some scintillation light are two requirements for materials to be used to construct a homogeneous hadron calorimeter (HHCAL) capable to measure both Cherenkov and Scintillation light. In this paper we report an investigation on lead based halide crystals for the HHCAL detector concept, including lead fluoride chloride (PbFCl) and gadolinium doped lead fluoride (PbF2:Gd) crystals grown at Shanghai Institute of Ceramics. The optical and scintillation properties of PbFCl and PbF2:Gd crystal samples, such as transmittance and photo-/x- luminescence spectra, light output and corresponding decay time, were measured at room temperature. Excellent UV cutoff edge and short decay time were found in PbFCl crystals. Further development work to improve PbFCl quality for the HHCAL project is discussed.