A proton tagging detector for the NA48 experiment

Abstract The concept of K S proton tagging and first prototype test results are reported from the NA48 experiment. Thin scintillator foils were arranged as two staircases intersecting in space. A geometric alignment to 0.4 mrad, a light yield of 300–400 photoelectrons and a time resolution of 70–90 ps with conventional TDCs were achieved. A FADC system operating at 450 megasamples/s performed at 50 ps intrinsic time resolution. Overlapping pulses could be resolved down to 7 ns.