Quality of a 28 cm long LYSO crystal and progress on optical and scintillation properties

摘要

Because of their high stopping power and fast and bright scintillation, cerium doped LSO and LYSO crystals have attracted a broad interest in the physics community pursuing precision electromagnetic calorimeter for future high energy physics experiments. Their excellent radiation hardness against γ-rays, neutrons and charged hadrons also makes them a preferred material for calorimeters to be operated in a severe radiation environment, such as the SLHC. An effort was made at SIPAT to grow 25 X0 (28 cm) long LYSO crystals for high energy physics applications. In this paper, the optical and scintillation properties and its radiation harness against γ-ray irradiations up to 1 Mrad are presented for the first 2.5 × 2.5 × 28 cm LYSO sample. An absorption band was found at the seed end of this sample and three other long samples, which was traced back to a bad seed crystal used in the corresponding crystal growth process. Significant progresses in optical and scintillation properties were achieved for large size LYSO crystals after eliminating this absorption band.