Speaker
Description
A DIRC-like TOF (DTOF) detector is chosen for particle identification (PID) at the super tau-charm facility (STCF) in the endcap region. A total timing precision of 50 ps (DTOF intrinsic ~30 ps) is required to achieve 4σ separation of π/K up to 2 GeV/c momentum, by combining both the TOF measurement and the multi-dimensional (timing-positional) information of Cherenkov photons. In this presentation the overall progress of DTOF study will be introduced.
A full-size endcap DTOF prototype has been developed and tested using cosmic ray. The prototype utilizes a large-size (0.56 m2) high-quality fused silica plate (surface roughness below 1 nm) as the Cherenkov radiator and 42 MCP-PMTs (Hamamatsu R10754) as photon sensor. A raw light yield of about 38 photons per cosmic-ray track was observed, and a single-track intrinsic time resolution of ~21 ps was achieved, both agreed well with the Monte Carlo simulation.
In the view of cost and difficulty in transportation, a smaller endcap DTOF prototype (1/3 of the full-size one) underwent beam tests for PID capability validation at CERN's PS T9 line, in mid-2024. This prototype achieves a 50 ps time resolution (including T0 ~44 ps) for hadron beams and a separation performance of 4.4σ for π/p at 4 GeV/c (equivalent to π/K separation at 2 GeV/c) , which is consistent with the cosmic ray results and fulfills the requirements of STCF
Given the excellent performance of the endcap DTOF, we plan to apply this scheme to the barrel region as back up of the barrel PID detector for STCF. The difficulty of this scheme lie in the higher ambiguity in reconstruction due to multiple lateral reflections, which is also the main difference compared to the endcap DTOF. Preliminary simulations indicate that this scheme is feasible. Therefore, a full-size barrel DTOF prototype is developed to validate its feasibility. Its construction and cosmic-ray test are planned in the near future (~May to July) and most-recent results will be presented.
