TORCH - A Cherenkov based time-of-flight detector

M. W U Van Dijk*, N. H. Brook, L. Castillo García, E. N. Cowie, D. Cussans, C. D'Ambrosio, J. Fopma, R. Forty, C. Frei, R. Gao, T. Gys, N. Harnew, T. Keri, D. Piedigrossi

*Corresponding author for this work

Research output: Contribution to journalArticle (Academic Journal)peer-review

16 Citations (Scopus)


TORCH is an innovative high-precision time-of-flight system to provide particle identification in the difficult intermediate momentum region up to 10 GeV/c. It is also suitable for large-area applications. The detector provides a time-of-flight measurement from the imaging of Cherenkov photons emitted in a 1 cm thick quartz radiator. The photons propagate by total internal reflection to the edge of the quartz plate and are then focused onto an array of photon detectors at the periphery. A time-of-flight resolution of about 10-15 ps per incident charged particle needs to be achieved to allow a three sigma kaon-pion separation up to 10 GeV/c momentum for the TORCH located 9.5 m from the interaction point. Given ~30 detected photons per incident charged particle, this requires measuring the time-of-arrival of individual photons to about 70 ps. This paper will describe the design of a TORCH prototype involving a number of ground-breaking and challenging techniques.

Original languageEnglish
Pages (from-to)118-122
Number of pages5
JournalNuclear Instruments and Methods in Physics Research, Section A: Accelerators, Spectrometers, Detectors and Associated Equipment
Publication statusPublished - 1 Dec 2014


  • Cherenkov radiation
  • Particle identification


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