The design and performance of a prototype water Cherenkov optical time-projection chamber

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• 作者：Eric Oberla ; ^{ejo@uchicago.edu" class="auth_mail" title="E-mail the corresponding author} ; Henry J. Frisch
• 关键词：Time-of-flight ; Cherenkov light ; Optical time projection chamber ; Microchannel plate photomultiplier ; Track reconstruction ; Particle detector
• 刊名：Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment
• 出版年：2016
• 出版时间：1 April 2016
• 年：2016
• 卷：814
• 期：Complete
• 页码：19-32
• 全文大小：4100 K

文摘

A first experimental test of tracking relativistic charged particles by ‘drifting’ Cherenkov photons in a water-based optical time-projection chamber (OTPC) has been performed at the Fermilab Test Beam Facility. The prototype OTPC detector consists of a 77 cm long, 28 cm diameter, 40 kg cylindrical water mass instrumented with a combination of commercial $5.1\&<font\; color="red">time</font>s;5.1{\mathrm{cm}}^2$ micro-channel plate photo-multipliers (MCP-PMT) and $6.7\&<font\; color="red">time</font>s;6.7{\mathrm{cm}}^2$ mirrors. Five MCP-PMTs are installed in two columns along the OTPC cylinder in a small-angle stereo configuration. A mirror is mounted opposite each MCP-PMT on the inner surface of the detector cylinder, effectively increasing the photo-detection efficiency and providing a time-resolved image of the Cherenkov light on the opposing wall. Each MCP-PMT is coupled to an anode readout consisting of thirty 50 Ω microstrips. A 180-channel data acquisition system digitizes the MCP-PMT signals on one end of the microstrips using the PSEC4 waveform sampling-and-digitizing chip operating at a sampling rate of 10.24 Gigasamples-per-second. The single-ended microstrip readout determines the time and position of a photon arrival at the face of the MCP-PMT by recording both the direct signal and the pulse reflected from the unterminated far end of the strip. The detector was installed on the Fermilab MCenter secondary beam-line behind a steel absorber where the primary flux is multi-GeV muons. Approximately 80 Cherenkov photons are detected for a through-going muon track in a total event duration of ~2 ns. By measuring the time-of-arrival and the position of individual photons at the surface of the detector to $\le 100\mathrm{ps}$ and a few mm, respectively, we have measured a spatial resolution of ~15 mm for each MCP-PMT track segment, and, from linear fits over the entire track length of ~40 cm, an angular resolution on the track direction of ~60 mrad.