The TORCH time-of-flight detector

Abstract

TORCH is a large-area time-of-flight (ToF) detector, proposed for the Upgrade-II of the LHCb experiment. It will provide charged hadron identification over a 2–20 GeV/c momentum range, given a 9.5 m flight distance from the LHC interaction point. To achieve this level of performance, a 15 ps timing resolution per track is required. A TORCH prototype module having a 1250×660×10 mm3 fused-silica radiator plate and equipped with two MCP-PMTs has been tested in a 8 GeV/c CERN test-beam. Single-photon time resolutions of between 70–100 ps have been achieved, dependent on the beam position in the radiator. The measured photon yields agree with expectations.