Performance of connected GSO bars

The performance of connected GSO (Gd2SiO5:Ce) bars was investigated using a proton beam of 0.6–1.0 GeV/c. Single crystals of 20 cm-long GSO with different Ce concentrations (1.5, 0.5 mol%) and cross-sections (1×1 cm2, 2×2 cm2) were prepared. Long GSO bars were constructed by connecting two crystals of the same type with or without a 10 cm-long plastic scintillator between the crystals.The position dependences of the pulse height, energy resolution and time resolution were investigated. At a typical proton momentum, 1.0 GeV/c, the best energy resolution was 4.8% for 2×2×20 cm3 GSO crystals doped with 0.5 mol% Ce due to the larger light yield, and the best position resolution was 0.55 cm for 1.5 mol% Ce due to the shorter attenuation length.