A cluster finding trigger processor for a high energy physics experiment searching for new source of CP violation

A trigger processor was designed, built, and used in a high-energy physics experiment which was designed to search for a second source of charge-conjugate-parity (CP) violation. An 804-element lead-glass array measured the energies and positions of the final state electromagnetic showers, called clusters. A cluster is defined as an island of connected glass blocks each with more than 1 GeV of energy deposited. The processor selected four clusters events which constituted less than 10% of the total. The trigger contributed negligible deadtime to the data acquisition system. Erasable programmable logic devices were used extensively to search in parallel for the clusters. A typical event took about 30 μs to be processed the reduction in trigger rate by more than one of magnitude resulted in an experiment that has the highest reported statistics and sensitivity for the measurement of the CP violation parameter ε"/ε