Beam Tests of First Prototype of a Cherenkov Counter for the ALICE T0 Detector

Abstract The first prototype of a Cherenkov counter consisting of a quartz radiator of rectangular shape 25x30x12 mm (30 mm along the particles' trajectories) and/or PMTs Hamamatsu R3432-01 and FEU-187 have been tested at proton/pion beam with 1.19 GeV/c momenta. Time resolution better than 50 ps (sigma) has been obtained for both types of the PMTs at different voltages. The dynamic ranges of both types of PMTs was measured with a pulsed laser (500 ps FWHM). For both types of the PMTs the dynamic range, with a time resolution of better than 50 ps, exceeds 100, thus providing cover to the expected dynamic range for the ALICE experiment for p-p, Ca-Ca and Pb-Pb runs. </HTML