Test-beam studies of a small-scale TORCH time-of-flight demonstrator

S. Bhasin, T. Blake, N. Brook, T. Conneely, D. Cussans, R. Forty, C. Frei, E. P.M. Gabriel, R. Gao, T. Gershon, T. Gys, T. Hadavizadeh, T. H. Hancock, N. Harnew, M. Kreps, J. Milnes, D. Piedigrossi, J. Rademacker, M. van Dijk

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TORCH is a time-of-flight detector designed to perform particle identification over the momentum range 2–10 GeV/c for a 10 m flight path. The detector exploits prompt Cherenkov light produced by charged particles traversing a quartz plate of 10mm thickness. Photons are then trapped by total internal reflection and directed onto a detector plane instrumented with customised position-sensitive Micro-Channel Plate Photo-Multiplier Tube (MCP-PMT) detectors. A single-photon timing resolution of 70ps is targeted to achieve the desired separation of pions and kaons, with an expectation of around 30 detected photons per track. Studies of the performance of a small-scale TORCH demonstrator with a radiator of dimensions 120×350×10mm3 have been performed in two test-beam campaigns during November 2017 and June 2018. Single-photon time resolutions ranging from 104.3ps to 114.8ps and 83.8ps to 112.7ps have been achieved for MCP-PMTs with granularity 4 × 64 and 8 × 64 pixels, respectively. Photon yields are measured to be within ∼10% and ∼30% of simulation, respectively. Finally, the outlook for future work with planned improvements is presented.

Original languageEnglish
Article number163671
Number of pages7
JournalNuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors, and Associated Equipment
Publication statusPublished - 1 May 2020
Externally publishedYes


  • Cherenkov radiation
  • LHCb upgrade
  • Micro-channel plate photo-multiplier tubes
  • Particle identification
  • Time-of-flight

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