R&D of particle identification devices with high-precision timing

We have studied micro-channel-plate photo-multiplier tubes (MCP-PMT), which realize timing measurements of the single photons with high precision of about 30 ps. We investigated the timing properties of 4 different types with a magnetic field, and measured the lifetime of the gain, quantum efficiency and transit time spread. application, we studied the timing resolution of TOF counters by means of Cherenkov-light detection with a MCP-PMT, and attained a 6.2 ps resolution using 3 GeV/c pion-beams with readout electronics of 4.1 ps resolution. As another application, we have developed a novel particle identification device, named TOP counter, which is a Cherenkov ring imaging counter with precise timing determination, especially for upgrading B-factory experiments. We performed beam tests with the prototype, and obtained the expected results.