Time resolution and high-counting rate performance of plastic scintillation counter with multiple MPPC readout

We have been developing a plastic scintillation counter for the WASA detector. The performance of a plastic scintillation counter with Multi-Pixel Photon Counter (MPPC) readout has been systematically investigated for minimum ionizing particles in terms of the time resolution and the signal amplitude stability. The performance was evaluated under various incident conditions of 2.5 GeV/c proton beams and with different MPPC settings. A plastic scintillator with a size of 550×38×8mm3 was optically coupled with multiple MPPCs at each plane with a size of 38×8mm2 for detecting the scintillation photons. The observed time resolution ranges in 37–80 ps (σ) depending on the incident positions and angles for the case of three MPPCs attached to each end. We found the time resolution and the signal amplitude fairly consistent up to the counting rate of 0.2 MHz.