Development of a pico-second start counter

The goal is to develop a hodoscope with a time resolution of less than 50 ps. To achieve this level of precision, the obvious choice is to use the Cherenkov effect because of the prompt photon-production. The detector itself consists of 64 fused-silica radiator bars (5 x 5 x 140 mm³) in an 8 x 8 matrix attached to an microchannel plate photomultiplier tube with 64 pixels (one bar per pixel). The segmented radiator design allows improving the time resolution depending on the number of traversed radiator bars. Also the number of detected photons per pixel is important as it improves the time resolution. Signal discrimination will be done using custom-made front-end electronics and a TRB3 system will be used for data acquisition. The performance of the detector is determined using a low intensity electron beam at the MAMI accelerator in Mainz with a momentum of 855 MeV/c. The obtained data are compared to detailed Monte Carlo simulations. In this contribution the experimental setup is described in more detail. Also first preliminary results from the test experiment are shown.