Speaker
Description
The proximity-focused Ring Imaging Cherenkov (pfRICH) detector plays a critical role in particle identification for the ePIC experiment. A laser-based monitoring system is being developed to ensure precise and reliable calibration throughout its operation. This system serves two key functions: measuring single-photon timing resolution (targeting <100 picoseconds) for precise time-of-flight calculation/calibration, and monitoring signal amplitude over time to detect potential degradation in photocathode efficiency and mirror reflectivity. The monitoring system uses a pulsed 405 nm picosecond laser, fiber-optic splitter, and a custom-designed 50-degree diffuser to achieve uniform light distribution across the detector.
TracePro software was used to simulate and optimize the propagation of laser pulses from fiber sources through the diffuser, including both direct and mirror-reflected paths to the sensors. Multiple configurations for diffuser geometry, fiber placement, and alignment with detector components were evaluated to maximize uniformity and closely replicate the expected Cherenkov photon light patterns. Initial results indicate that the optimized system achieves the necessary coverage and timing verification for effective in-situ calibration. This laser monitoring approach and R&D experience will be adapted to support the construction and operation of other Cherenkov detector systems in the field of nuclear physics.
