Time of Flight Detector (TOF)
High-resolution TOF provides a very attractive solution for PID covering the lower momenta range at the EIC, below the turn on threshold for gas RICH detectors. The R&D pursued here intends to push the state of the art of two technologies, MCP-PMT and mRPC, with an ultimate goal of 5 and 10 ps, respectively. Assuming a total resolution of 10 ps and a distance of 1 m, TOF could achieve 3σ separation for π/K and K/p of 3.5 and 6 GeV, respectively, which would be adequate for mid-rapidity PID. In the hadron going direction, where the TOF wall could be placed 3 m from the interaction point, the 3σ separation for π/K and K/p would be 6.5 and 11 GeV. Coupled with a dE/dx measurement from a TPC, TOF would also provide electron identification up to several GeV. Besides PID, TOF enables bunch association, which is required since each bunch may have a different polarization.
TOF walls are also very compact. The TOF detectors proposed here are only about 2 cm thick and would fit in the available space of 10 cm in the ePHENIX barrel, even after a tilt to make them projective toward the IP. The cost of a mRPC-based TOF also makes them a very attractive option. Based on estimates from existing systems, a cost of about $200K/m2 is estimated for mRPC TOF. eRD14 is also pursuing TOF using LAPPD MCP-PMTs, which should be over an order of magnitude cheaper than MCP-PMTs from current vendors.