高计数率环境下超高时间分辨飞行时间谱仪关键技术研究

Time of flight system (TOF) based on MRPC technology is widely used and played an important role in modern high energy nuclear physics experiments. With the increase of accelerator energy and luminosity, many experiments have increasingly demand on the TOF for particle identification to have high resolution TOF under high data rate environment, which undoubtedly presents a big challenge to the TOF technology. For example, the JLab-SoLID spectrometer requires a TOF for Kaon/pion separation up to momentum of 7 GeV/c under high particle rate of 20 KHz/cm^2. It is imperative to develop ultrahigh resolution TOF system which can handle high rate. We propose, based on the most advanced state-of-art world technology, to develop high-rate narrow-gap MRPC detector with corresponding readout electronics system. The readout electronics system is based on high-speed wave-form digitization system with fast amplifier. Alternative option using FPGA based TDC system with fast discriminator will also be studied. The goal is to develop a new prototype TOF system with time resolution reach around 20 ps and can handle rate up to 20 KHz/cm^2. This system will meet the urgent experimental needs, greatly enhance our technical capability in particle detection and push the development in high precision detection technology and high-speed high precision electronics system in China.

基于多气隙电阻板室（MRPC）技术的飞行时间谱仪在现代物理实验的粒子鉴别中得到了广泛应用，发挥了重要作用。随着加速器能量和对撞机亮度的提高，一些物理实验要求在高计数率环境下达到对特定粒子的精确鉴别，这无疑是飞行时间谱仪技术的挑战。如JLab-SoLID谱仪要求其飞行时间探测器在20 kHz/cm^2的计数率环境下对K/PI分辨动量上限达到7GeV/c。因此研制高计数率，超高时间分辨的飞行时间谱仪势在必行。本项目在跟踪国际前沿技术基础上，自主研制高计数率窄气隙MRPC，并基于高速波形数字化和快甄别结合可编程器件FPGA TDC两种方案进行高精度时间测量电子学技术研究，研制出时间分辨达20ps，计数率能力达20 kHz/cm^2的新型飞行时间探测器系统，满足物理实验的迫切需求，全面提升我国在粒子探测领域的研究实力，推动我国在高精度粒子探测技术、高速高精度电子学等相关领域的发展。

本课题聚焦于未来高亮度高精度物理实验中粒子鉴别的迫切需求，围绕研制高计数率超高时间分辨飞行时间谱仪的核心内容，开发出一套完整的MRPC探测器信号形成及定时性能模拟程序，研制出时间抖动小于10ps的前端信号放大器和相应的高速波形采用电路，同时研制出基于TOT技术的前端放大器+高精度TDC的信号读出技术，研制出多个窄气隙的MRPC探测器，创新性提出了应用机器学习技术重建MRPC时间性能的技术并研究出了独特的集成神经网络。测试结果表明在计数率高达15kHz/cm2时，系统时间分辨优于20ps，MRPC 时间分辨率达到16ps，达到国际领先水平。该技术将在大型物理实验及TOF-PET系统中得到广泛应用。