The TORCH time-of-flight detector

The TORCH detector is a time-of-flight system that is being developed for use in particle physics experiments with the aim of providing particle identification, over a wide area, in the momentum range 2 to 10 GeV/c. The detector exploits prompt Cherenkov light produced by charge particles traversing a 10 mm thick quartz plate. Photons propagate via total-internal reflection and are focussed onto a detector plane comprising position-sensitive micro-channel plate photomultiplier (MCP-PMT) detectors. The goal is to achieve a resolution of 15 ps per particle by combining information from around 30 detected photons, given a single-photon resolution of 70 ps. The MCP-PMT detectors have been developed with a commercial partner (Photek), leading to the delivery of a square tube with a 53-by-53 mm active area and 8-by-128 pixel equivalent. A small-scale TORCH demonstrator has been operated in beam tests and preliminary results indicate a single-photon resolution better than 100 ps. Progress towards a larger-scale system with 11 MCP-PMTs is presented.