Design of a LYSO Crystal Electromagnetic Calorimeter for Dark Photon Detection in the DarkSHINE Experiment

This paper presents the design and optimization of a LYSO crystal electromagnetic calorimeter (ECAL) for the DarkSHINE experiment, which aims to search for dark photons as potential mediators of dark forces. The ECAL design was evaluated through comprehensive simulations, focusing on optimizing dimensions, material selection, energy distribution, and energy resolution. The ECAL configuration consists of 21$\times$21$\times$11 LYSO crystals, each measuring 2.5$\times$2.5$\times$4 cm$^3$, arranged in a staggered layout to improve signal detection efficiency. A 4 GeV energy dynamic range was established to ensure accurate energy measurements without saturation, which is essential for background rejection and signal identification. A detailed digitization model was developed to simulate the scintillation, SiPM, and ADC behaviors, providing a more realistic representation of detector’s performance. Additionally, the study assessed radiation damage in the ECAL region, highlighting the necessity of radiation-resistant scintillators and silicon sensors.

本论文针对DarkSHINE实验设计并优化了硅酸钇镥（LYSO）晶体电磁量能器（electromagnetic calorimeter, ECAL），该实验旨在搜寻作为暗力潜在媒介子的暗光子。该ECAL的设计通过全面的模拟仿真进行评估，重点围绕尺寸优化、材料选型、能量分布与能量分辨率展开。该ECAL的构型由21×21×11块LYSO晶体组成，单块晶体尺寸为2.5×2.5×4 cm³，采用交错排布以提升信号探测效率。设置了4 GeV的能量动态范围，以确保能量测量的准确性且不会出现饱和，这对于本底抑制与信号识别至关重要。研发了一套精细化的数字化模型，用于模拟闪烁体、硅光电倍增管（silicon photomultiplier, SiPM）与模数转换器（analog-to-digital converter, ADC）的工作特性，从而更真实地还原探测器的性能表现。此外，本研究还评估了ECAL区域的辐射损伤情况，强调了抗辐射闪烁体与硅基传感器的必要性。