一种基于Micromegas探测器的高计数率精确定时技术

下一代强子对撞机实验面临的一项严峻挑战是如何应对高亮度带来的强烈堆积效应。通过精确测量末态带电粒子到达时间从而重建对撞时间可以有效解决这一问题。因此，在高计数率环境下对带电粒子进行精确定时是下一代强子对撞机实验对探测器的一项关键需求。本项目针对这一需求研究基于MicroMegas(MM)探测器的高计数率精确定时技术。在探测器方面，将研制MM结构结合契伦科夫技术构成的高时间分辨探测器，同时研究针对大面积应用的各种关键技术，实现探测器的可扩展性和稳定可靠性。在电子学方面，将研究高带宽、高增益前置放大结合高速波形采样的高精度时间测量技术，实现15 ps的测量精度。最终研制一台有效面积达20cm*20cm、颗粒度达1cm*1cm的精确定时MM探测器及配套读出电子学，系统时间分辨达到30ps。本项目研究将为下一代对撞机实验发展关键探测器和相关电子学技术，此技术在医学成像等其他领域也有极大的应用潜力。

One big challenge faced by next-generation hadron collider experiments is how to handle immense pile-up effects under high luminosity conditions and minimize the impact of pile-up effects on detection of interesting physics processes. Performance of the experiments at next-generation hadron colliders would be severely compromised without mitigation of pile-up effects, making the colliders incapable of reaching their full potential. Simulation studies have found precise timing information of final-state particles can be exploited to significantly enhance vertex separation power by timing vertices. The pile-up effects can then be effectively addressed. So it is one of the important demands on detectors from next-generation hadron collider experiments to precisely time charged particles in high-rate environments present at hadron colliders. Targeting this demand, this project proposes R&D on a fast timing technology based on a MicroMegas detector. The proposed R&D program covers both the detector and electronics aspects of the technology. In the detector aspect, a fast timing detector combining a MicroMegas structure with components for a Cherenkov detector will be developed. Various critical technologies concerning large-area application of this detector in high-rate experiments will be studied and developed to ensure the scalability and reliability of the detector for actual application. In the electronics aspect, a readout electronics technology for high-precision time measurement using high-bandwidth and high-gain pre-amplification followed by high-speed waveform digitization will be studied and developed for the MicroMegas-based fast timing detector. The readout electronics aims at a precision of 15ps for time measurement. Based on both the detector and electronics technologies to be developed in this project, a large-size prototype of the MicroMegas-based fast timing detector ( effective area: 20cm*20cm, spatial granularity: 1cm*1cm ) equipped with up to 100 channels of readout electronics will be built to achieve a time resolution of 30 ps at the system level. This would demonstrate the suitability of the fast-timing technology for large-area application. The R&D program proposed for this project will develop key detector and related electronics technologies for next-generation hadron collider experiments. The fast-timing technology to be developed will also have great potential applications in other fields such as medical imaging.