Design and Test of the BESIII ETOF with MRPC Technology

The Time-of-Flight (TOF) detector is the key detector in the Beijing Spectrometer (BESIII) for charged hadron identification [1], [2]. It is composed of the barrel TOF (BTOF) and the end-cap TOF (ETOF). The BTOF consists of two-layer plastic scintillators and fine-mesh Photo-Multiplier Tubes (PMT) as readout. Its time resolution achieves 80ps for muon samples at 1GeV/c [3]. On the other hand, the previous ETOF is single-layer scintillator detector. There is a significant multiply scattering effect leading to relatively poor time resolution of ~ 140ps, limiting the K/π separation (3σ) momentum range below 1GeV/c [4]. In order to improve its performance, the BESIII-TOF group has upgraded the ETOF based on high time resolution Multi-gap Resistive plate Chamber (MRPC) technology. Experiment and simulation results show that the MRPC-based ETOF can effectively suppress the multiple scattering effect on the intrinsic time resolution and uncertainty of particle hit positions. For the upgraded ETOF system with a proposed time resolution of 80ps, K/π separation can achieve 1.4GeV/c at 95% confidence level.