Beam tests of a large-scale TORCH time-of-flight demonstrator

• Published in: Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment Accelerators, spectrometers, detectors and associated equipment, 2020-04, Vol.958, p.162060, Article 162060
• Main Authors: Hancock, T.H., Bhasin, S., Blake, T., Brook, N., Conneely, T., Cussans, D., Frei, C., Forty, R., Gabriel, E.P.M., Gao, R., Gershon, T., Gys, T., Hadavizadeh, T., Harnew, N., Kreps, M., Milnes, J., Piedigrossi, D., Rademacker, J., van Dijk, M.
• Format: Article
• Language: English
• Subjects: Cherenkov radiation; LHCb upgrade; Micro-channel plate photo-multiplier tubes; Particle identification; Time-of-flight
• ISSN: 0168-9002; 1872-9576
• DOI: 10.1016/j.nima.2019.04.014

The TORCH time-of-flight detector is designed to provide particle identification in the momentum range 2−10GeV∕c over large areas. The detector exploits prompt Cherenkov light produced by charged particles traversing a 10mm thick quartz plate. The photons propagate via total internal reflection and are focused onto a detector plane comprising position-sensitive Micro-Channel Plate Photo-Multiplier Tubes (MCP-PMT) detectors. The goal is to achieve a single-photon timing resolution of 70ps, giving a timing precision of 15ps per charged particle by combining the information from around 30 detected photons. The MCP-PMT detectors have been developed with a commercial partner (Photek Ltd, UK), leading to the delivery of a square tube of active area 53×53mm2 with a granularity of 8×128pixels equivalent. A large-scale demonstrator of TORCH, having a quartz plate of dimensions 660×1250×10mm3 and read out by a pair of MCP-PMTs with custom readout electronics, has been verified in a test beam campaign at the CERN PS. Preliminary results indicate that the required performance is close to being achieved. The anticipated performance of a full-scale TORCH detector at the LHCb experiment is presented.