The CBM time-of-flight wall

The Compressed Baryonic Matter spectrometer (CBM) is a future heavy ion experiment located at the Facility for Anti-proton and Ion Research (FAIR) in Darmstadt, Germany. The main interest of CBM is the investigation of the phase diagram of strongly interacting matter in the region of the highest baryon densities. In order to measure the necessary observables with unprecedented precision an excellent particle identification is required. The key element in CBM providing hadron identification at incident energies between 2 and 35 AGeV will be a 120 m² large Time-of-Flight (ToF) wall composed of Multi-gap Resistive Plate Chambers (MRPC) with a system time resolution better than 80 ps. The most demanding challenge, however, is the enormous incident particle fluxes between 100 Hz/cm² and 25 kHz/cm² generated at the highest interaction rates (10 MHz) that CBM is designed for. The current conceptual design of the ToF-wall will be presented. We will show various MRPC prototypes developed by the CBM-Tof group. In order to elaborate the final MRPC design of these counters heavy ion test beam times were performed at SPS/CERN. In this contribution we present performance test results regarding time resolution, efficiency, cluster size and rate capability for several counter types.