R&D of the endcap TOF detector for BESIII

The Endcap TOF (ETOF) of Beijing Spectrometer(BESIII) is consisted of 2x48 pieces of trapezoidal scintillator. Its main physics goal is to realize 2 sigma pi/k separation at momentum up to 0.8GeV/c, and to reach the intrinsic time resolution of 80ps. In this paper, the properties of photomultiplier tube(R5924) and plastic scintillators (BC404, BC408, EJ204) are studied, a ETOF module with different wrappings is tested with the beam of 800MeV electron at IHEP. The results show that the time resolution of an ETOF module using scintillator BC404 or EJ204 is below 80ps which includes the electronic fluctuation. The ESR wrapping can efficiently enhance the amplitude of the output pulse and improve the performance of the TOF detector.