High rate MRPC technology for TOF systems and beyond

Multi-gap resistive plate chamber (MRPC) technology has become one of the most important detector solutions for time-of-flight (TOF) systems because of their good time resolution, high efficiency, suitability for constructing large-area TOF walls by tiling many modules, and relatively low cost. However, with the increase in accelerator luminosity and event rate, traditional float-glass MRPCs face challenges under high particle flux, including rate-induced voltage drop on resistive plate electrodes, gas contamination and aging, and local instability around spacer regions. These effects directly limit the rate capability, long-term stability, and time resolution of MRPC detectors in TOF system. We summarize recent progress in high rate MRPC technology on three main optimization directions. The first is resistive plate electrode optimization using low resistive glass. This reduces the average voltage drop under irradiation, allowing the detector to maintain an efficiency above 90 % and a time resolution better than 80 p s at particle fluxes up to 60 k H z / c m 2 . The second is gas flow and exchange optimization using sealed MRPC structures. This design reduces the internal gas volume by a factor of about 50 and enables stable operation at a low gas flow rate of 1 m l / m i n , effectively mitigating gas-related aging effects. The third is spacer-related optimization using improved spacer designs like pad spacers and thermal-bonding spacers. These designs decrease the local electric-field distortion by more than a factor of three and reduce the noise rate by two orders of magnitude, significantly improving long-term stability. Experimental results from beam tests and X-ray tests show that these optimization directions are effective and complementary. These developments provide a practical technological route for MRPC detectors operating in high particle flux experiments such as CBM-TOF.