A TOF counter of σ ∼ 10ps with Cherenkov photons and a MCP-PMT

Abstract

We measured timing properties of 4 different types of micro-channel-plate photo-multiplier tubes (MCP-PMT) by irradiating with single photons with/without a magnetic field (B); resulted time resolutions are σ= 30 -35 ps for single photons under B = 1.5 T. A small Time-Of-Flight (TOF) counter comprised a thin quartz Cherenkov-radiator and a MCP-PMT has been tested using π-beam. The time resolution of σ= 10.6 ps has been attained. Index Terms-TOF, Cherenkov light, MCP-PMT.A Time-Of-Flight (TOF) counter, which consists of a photon radiator and a photo-detector, is one of the popular devices in high energy physics experiment for identification of particle species. Its time resolution is basically limited by fluctuations of timing and numbers of emitted photons and of propagation length, and the timing property of photo-detector.In our study, the photons by Cherenkov radiation instead of scintillation radiation are employed using a quartz instead of a scintillator to reduce the time fluctuation of photon emission. Also, photon propagation length is managed to have its smallest fluctuation by arranging the relationship between the TOF counter and the incident particles, as described later. In order to realize these features into the TOF time resolution, we use a MCP-PMT as the photo-detector. The measured timing performances of MCP-PMT's are first discussed.