Project NICA/MPD is dedicated to study of hot and dense baryonic matter in collisions of heavy ions (up to Au$^{+79}$) in energy region $4\leq \sqrt{S_{NN}} \leq 11$ GeV. The ToF system of MPD is the main detector for particles identification. It has to have time resolution better than 100 ps for separate pion/kaon in the momentum range 0-2.5 GeV/c and proton/kaon in the range 0-4.5 GeV/c. The stop signal for ToF measurments is given by barrel of Multigap Resistive Plat Chambers (MRPC). The start signal for ToF measurements is given by stations of Cherenkov quartz counters (FFD - Fast Forward Detector).

A modular Cherenkov detector with picosecond time resolution is developed and created at LHEP/JINR in Dubna. The aim of this detector is production of start signal for ToF detector and fast triggering. This goal is achieved by registration of high-energy photons and charged pions in the detector modules based on MCP-PMTs XP85012/A1- Q from Photonis. The high-energy photons are detected via conversion to electrons in 10-mm lead layer in front of the 15-mm quartz radiator. The detector concept, module characteristics, and the detector performance studied by MC simulation and by using deuteron beam of Nuclotron are discussed. The time resolution of the detector module obtained in ToF measurements on deuteron beam is 24 ps for DRS4 digitizer readout and 37 ps for TDC (HPTDC chip) readout.

Laboratory of High Energy Physics, Joint Institute for Nuclear Research, Joliot Curie 6, Dubna, 141980, Russia