Speaker
Description
High-granularity electromagnetic calorimeters employing long scintillator bars have attracted increasing interest for future collider experiments. Compared with conventional BGO crystals, BSO provides a promising alternative due to its faster scintillation decay time and cost advantage, making it a potential candidate for future ECAL applications.
In this work, we present a systematic performance study of BSO crystal bars with dimensions of $2 \times 2 \times 12\ \mathrm{cm}^3$ for a high-granularity calorimeter prototype. Beam tests at the CERN PS-T9 beamline and complementary laboratory measurements with a collimated $^{137}\mathrm{Cs}$ source were performed to characterize the scintillation response and spatial uniformity of the crystals. The beam test demonstrates an average MIP response of $282\ \mathrm{p.e.}/\mathrm{MIP}$ with intra-crystal non-uniformity below $1\%$, while the observed inter-crystal response variation can be correctedthrough calibration. Laboratory measurements further investigate the intrinsic response uniformity of individual crystals. In addition, simulations at different levels, including optical, prototype-level, and detector-level simulations, were performed to evaluate the impact of crystal response variations on calorimeter performance.
The results indicate that BSO provides sufficient light output to achieve the required calorimeter performance, supporting its feasibility as a cost-effective scintillator option for future high-granularity ECAL systems.
