Global optimization for light concentrators of a Geiger-mode cosmic-ray Cherenkov calorimeter

Light concentrators are crucial devices for photon-counting instruments, the optical characteristics of which affect the photoelectric response for the sensors. The designs that only aim to the light transmission have been proved far from optimum for the Geiger-mode calorimeters due to the significant influence from the angle-dependent reflectance, versatile light trajectories, and saturation of fired avalanche photodiodes (APDs). In this paper, we took into account these coupling effects, presented a novel approach to solve the problems in global optimization for light concentrators in combination with silicon photomultiplier (SiPM). In addition, a new probability method is studied and used to restore the photon counting for precise reconstruction of cosmic-ray air showers. The Monte-Carlo experiment verified that the new system design features a high accurate energy scaling for cosmic-ray measurement. The results also indicate that the precision is able to be improved by at least one order in magnitude.