A fast processor for muon triggering using resistive plate chambers

The authors report on the realization of a fast processor for muon trigger that was used in the WA92 experiment at CERN. The trigger was designed to identify secondary vertices or large transverse momentum tracks or leptons. The identification of muon tracks was done on two planes of resistive plate chambers (RPCs) with dimensions of 2×6 cm², placed behind an iron absorber. The RPC is a type of inexpensive gaseous detector suitable for covering large areas. It detects particles that cross a gas mixture, giving on a strip-line an induced signal of ~100 pC and ~2 ns risetime. The muon trigger was implemented by a VME hardware processor that had a processing time of ~90 ns