The CBM Time-of-Flight system

Abstract

The Compressed Baryonic Matter spectrometer (CBM) is a future fixed-target heavy-ion experiment located at the Facility for Anti-proton and Ion Research (FAIR) in Darmstadt, Germany. The key element in CBM providing hadron identification at incident beam energies between 2 and 11 AGeV (for Au-nuclei) will be a 120 m$^2$ large Time-of-Flight (ToF) wall composed of Multi-gap Resistive Plate Chambers (MRPC) with a system time resolution better than 80 ps. Aiming for an interaction rate of 10 MHz for Au+Au collisions the MRPCs have to cope with an incident particle flux between 0.1~kHz/cm$^2$ and 100~kHz/cm$^2$ depending on their location. Characterized by granularity and rate capability the actual conceptual design of the ToF-wall foresees 6 different counter granularities and 4 different counter designs. In order to elaborate the final MRPC design of these counters several heavy-ion in-beam and cosmic tests were performed. In this contribution we present the conceptual design of the TOF wall and in particular discuss performance results of full-size MRPC prototypes.