The tagging detector of the NA48 experiment

First test results are reported from the NA48 K s tagging system. The system consists of two subdetectors. One samples the passing time of each proton which will hit the K s target ( tagging detector ), the other one measures the event time of a charged Kaon decay ( hodoscope for charged decays ). The tagging detector was read out with a FADC system operating with a sampling frequency of 480MHz. A time resolution of 182ps and resolving of double pulses down to 4ns could be achieved.