Fabrication and testing of Novel 20 gas gaps double-stack Multi-gap Resistive Plate Chamber (MRPC) with multi-layer Copper converters and reduced HV for high energy gamma detection

Abstract

Resistive Plate Chambers (RPCs) are cost-effective detectors with fast signal, excellent time and spatial resolution for charged particle detection. These detectors can be also good candidates for medical imaging purposes like PET. Although, low efficiency of gaseous detectors limits their usage for high energy gamma detection, but it is possible to improve the detection efficiency by proper gamma to electron converter material and multi-layers of RPCs (MRPCs). In common RPCs, increasing the number of layers is limited by the large amount of applied High Voltage (HV). To overcome this problem, which is important for secure medical imaging system, the double-stack mode configuration is used in such a way that the RPCs are physically serial, but electrically parallel. In this work, A 20 gap MRPC with 160μ m of Copper converters and 150μ m gas gaps is fabricated. For this purpose, each metal sheet sandwiched between two thin resistive glasses. The metal electrodes are also used to apply separate HV to each gas gap. By using the proposed configuration, the applied HV can be reduced to 1.2kV for whole system. The simulation results show that the detection efficiency for 661keV Cs-137 gammas with 160μ m of Copper converter is around %5, which is in good agreement with experimental results.