Micro-Pattern Gas Detectors for Charged-Particle Tracking and Muon Detection

In the context of the 2013 APS-DPF Snowmass summer study conducted by the U.S. HEP community, this white paper outlines a roadmap for further development of Micro-pattern Gas Detectors for tracking and muon detection in HEP experiments. We briefly discuss technical requirements and summarize current capabilities of these detectors with a focus of operation in experiments at the energy frontier in the mediumterm to long-term future. Some key directions for future R&D on Micro-pattern Gas Detectors in the U.S. are suggested. I. Physics drivers and justification Exploration of virtually all physics at the energy frontier needs high-performing particle tracking  even jet physics since jet reconstruction in calorimeters with particle flow algorithms has now become standard. Study of any physics process with at least one high-pT muon in the final state requires robust muon identification and triggering. These capabilities are core requirements for all physics at the current and future energy frontiers, such as searches for new physics and standard model precision measurements, in particular in the newly opened Higgs sector. The high-rate environments at the current energy frontier, i.e. LHC phases 1 and 2, and at future high-energy colliders (high-energy LHC, ILC, CLIC, muon collider) drive much of the development of advanced Micro-pattern Gas Detectors (MPGD’s) to provide robust particle tracking, muon identification and muon triggering in increasingly harsh radiation environments. We note that applications of MPGD’s also extend into radiation detection and particle tracking in areas outside of HEP and NP, e.g. medical imaging [1] and homeland security [2]. II. Technical requirements on advanced MPGD’s for tracking and muon detection Muon detectors in HEP experiments typically cover areas of many square meters. Consequently, economic construction of large-area MPGD’s is mandatory for muon detector systems. The anode structures for signal pickup in MPGDs should be optimized to save cost by minimizing the required number of electronics channels while maintaining or improving performance. Using MPGD’s as tracking detectors requires highest tolerance against radiation damage and high-rate capability. We suggest a rate capability of O(100 MHz/cm) at minimal discharge rates as a benchmark R&D goal. Lowest detector mass is desired to minimize multiple scattering and bremsstrahlung in trackers. Very high spatial resolution of O(10 μm) for normal incidence could make MPGD trackers competitive with silicon-based trackers in terms of performance, but at potentially considerably lower cost. High detection efficiencies for charged particles very near to 100% and good time resolution of O(1 ns) will enable fully efficient track and muon triggering.