The CBM Time-of-Flight system

TL;DR

The paper presents the conceptual design and performance evaluation of the Time-of-Flight system for the CBM experiment, utilizing MRPC technology to achieve high-resolution particle identification at high interaction rates.

Contribution

It introduces a detailed conceptual design of the CBM ToF wall and provides performance results from full-size MRPC prototypes tested under relevant conditions.

Findings

Achieved system time resolution better than 80 ps.

Demonstrated MRPC prototypes can handle high particle fluxes.

Validated design choices through beam and cosmic tests.

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.