QUARTIC: A Fast Time-of-flight Counter

We present preliminary studies of a fast time-of-flight counter. This counter makes use of the Cerenkov effect to provide precise timing (10 to 30 psec scale) for protons scattered at small angles. One application is a proposed upgrade to the ATLAS and CMS detectors (FP420) that adds proton taggers 420 m upstream and downstream of the central detectors. Fast time-of-flight counters could be used to dramatically decrease backgrounds to events with a massive central system and forward/backward protons, by using timing to confirm that the protons originate from the same event vertex as the central system.