A fast on-line trigger for events with multiple high transverse momentum tracks

Abstract We present a fast (30 μs) on-line trigger that selects, from 300 GeV/ c π − interactions, events with three tracks of transverse momentum larger than 0.9 GeV/ c . The essential features of this trigger are a fast read-out (300 ns per cluster) of wire chambers, situated on the chamber frame, and a digital computation of transverse momenta that can cope with multiple hits in the detectors of the trigger tracks. The digital computation is done with standard MBNIM modules.