Tests of a High Resolution Time of Flight System Based on Long and   Narrow Scintillator
  We have tested a prototype time-of-flight system based on bulk scintillator block of dimensions $2.5 \times 2.5 \times 200$ cm. Using a calibration scheme similar to the one used in actual collider experiments, we have achieved a resolution of 71 ps using Amperex XP2020/UR photomultipliers and 81 ps using proximity-focusing fine-mesh photomultipliers (Hamamatsu R2021). Results are also obtained for scintillating fiber blocks of the same dimensions. Good internal reflectivity of the bulk scintillator block resulted in resolutions superior to the fibre blocks. A single-photon pulsed laser system was used to study photomultipliers and the results were used in a Monte Carlo simulation of the system to study the critical elements that determine the resolution. 
E. Chen, M. Saulnier, W. Sun and H. Yamamoto