Measurement of New Type Multi-strip Multi-gap Resistive Plate Chambers

The production of the multi-strip multi-gap resistive plate chambers for FOPI’s Timeof Flight (TOF) upgrade was accomplished. In order to assure the timing performance and quality of all detectors in the mass production, a quality assurance chain for the counters was implemented. First, the high voltage (HV) test was performed to assure its HVstability up to 11 kV (125 kV/cm) and to determine the dark rates of the detectors. Then, the performance of all counters with calibrated electronics was tested using a gamma source and proton beam. For proton beam, the timing resolution of MMRPC can reach to 75 ps, and the efficiency can be better than 98%.