Application of the FAMP multiprocessor system in experiment NA11 at the SPS

A second level trigger system is discussed, which will be implemented in the experiment NA11 at the CERN-SPS. The experiment studies hadron interactions with a two magnet single-arm spectrometer. The second level trigger will select events depending on kinematical and topological conditions. It uses the FAMP microprocessor system, which will operate on information from a set of MWPCs and Cerenkov counters. The microprocessors will reconstruct tracks, calculate momenta and determine the invariant mass of pairs of particles. An outline is given of the trigger set-up and of the track reconstruction procedures. Also results are presented of simulation studies, using experimental data and a provisional set-up of the microprocessor system. The reconstruction time per event is estimated to be about 0.5 ms. (6 refs).