A Versatile Secondary Trigger for a Multi-Detector System

The electronics of a secondary trigger for particle physics is described. The system has several desirable features that solve track recognition problems in situations where several subsystems of various cell configurations participate in the decision making. Track curvature and multiplicity are the criteria used. Versatility is attained through the use of Programmable Array Logic (PAL) and a 48-bit wide ROM-based sequencer that determines, with the resolution of a cell, the participation of each element in the decision process. Data from layers with arbitrary numbers of cells are shifted in a programmable manner through a PROM mask containing eight different track definitions. The results of any one of the eight triggering criteria are available 5.6 μs after the end of drift interval.