Monte Carlo simulation of BES III end-cap TOF

The End-Cap TOF (ETOF) of Beijing Spectrometer (BES III) consists of 2 x 48 pieces of trapezoidal scintillator (BC408). Its main physics goal is to realize the 2σ π/k separation at momentum up to 1 GeV/c, and to obtain TOF intrinsic time resolution of 80 ps. In order to study the effects of several factors on the intrinsic time resolution of ETOF, the Monte Carlo simulation of the detector is carried out by using Geant4 software package. The performance of ETOF at different conditions, such as scintillator covered materials, shapes, and particle hit positions, is simulated and discussed in detail. The result can provide a reference for the design of ETOF detector in BES III. (authors)