A parallel pipelined dataflow trigger processor
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This thesis describes the details of a parallel data flow trigger processor which is used in Fermilab’s E789. E789 is an experiment to study charmless two- prong decays and other low-multiplicity decays of particles containing b or c quarks. The trigger processor’s sole purpose is to determine, by postulating particle tracks, whether interesting particles exist in the current analysis period. The author has designed, implemented and tested the trigger processor. The single most significant contribution was the design of the vertex processor. The vertex processor utilizes silicon detector hits to calculate the particle origin and to verify particle track consistency with the downstream particle track. The capability to calculate particle origin did not exist in previous trigger processors. The processor consists of an upstream vertex processor and a downstream track processor. The algorithms which reconstruct the postulated particle paths and calculate particle origin are implemented via interconnected function specific hardware modules. The algorithm is directly dependent upon the organization of the modules, the specific arrangement of the inter-module cabling, on-board wire patch patterns, and where appropriate, on-board memory data. The processor provides an indication of the presence of at least one interesting particle pair in the current event by asserting Read on its Read/Skip output. The Read assertion is then used as a trigger to capture all of the event’s data for subsequent extensive off-line analysis.