新型 TORCH探测技术研究

TORCH(Time Of internally Reflected CHerenkov light detector) is an innovative DIRC-like Time-Of-Flight detector for high energy charged particle identification. It achieves a high level of performance at the extreme data taking conditions under high luminosity and high backgrounds. It is composed of a Fused Silica radiator connected to fast Photomultiplier(MCP-PMT or SiPM) array, readout by a dedicated front-end electronics. The challenge comes from the fact that the limited flight length for charged particles in detectors requires its timing measurement better than 20 ps, summing up all uncertainties. Having no equivalent in the history of HEP experiments, TORCH technology (including its Cherenkov scintillator manufacture, high-resolution fast PMT, high-speed USB Wave-digitizing electronics and pico-second timing method) should undergo an important validation phase. This research will greatly contribute to the development of our high energy particle detection technology.

TORCH(Time Of internally Reflected CHerenkov light detector)是一种新型DIRC-Like 飞行时间探测器，其最大特点是在极高亮度和本底噪声环境下的高性能带电粒子鉴别能力。TORCH由轻薄的硅（石英）闪烁体连接多通道光电倍增管（MCP-PMT)和复杂的前端电子学构成，其技术的挑战性在于: 它要求极高的时间分辨能力(<20ps), 以保证在很短的飞行距离范围内鉴别带电粒子。TORCH涉及一系列新技术和新方法，在目前的高能物理实验中还没有大规模运用的先例。本项目以TORCH探测技术研究突破口，通过对契仑柯夫光辐射体特性，新型SiPM性能，高速读出电子学以及皮秒定时方法的深入研究，以实现大面积高时间分辨DIRC-Like TOF探测技术的创新，为我国实验粒子物理和相关探测技术发展提供技术支持。

为了满足新一代大型加速器物理实验中高亮度，高动量带电粒子鉴别的需求，采用切伦科夫探测技术来进行粒子鉴别，可以大幅拓展其动量覆盖范围（几个GeV/c～几百GeV/c），并适用于高计数率实验场合。本项目借鉴切伦科夫光探测器对高动量带电粒子的快速响应特性，结合新型飞行时间测量技术，研制一种基于内反射切伦科夫光探测的超高时间分辨TOF探测器原型：TORCH (Time Of internally Reflected CHerenkov light detector)。TORCH由结构紧凑的石英辐射体，高速光电探测阵列（MCP-PMT或SiPM），以及皮秒定时电子学构成。模拟和测试结果显示其本征时间分辨可达~30ps，实现2GeV/c动量下的3 /分辨。为预研中的新一代大型加速器实验：超级陶粲装置（Super Tau-Charm Facility，STCF）等提供重要技术支持。