PROGRAMMABLE ACTIVE MEMORIES IN REAL-TIME TASKS - IMPLEMENTING DATA-DRIVEN TRIGGERS FOR LHC EXPERIMENTS

The future Large Hadron Collider (LHC), to be built at CERN, presents among other technological challenges a formidable problem of real-time data analysis. At a primary event rate of 40 MHz, a multi-stage trigg er system has to analyze data to decide which is the fraction of event s that should be preserved on permanent storage for further analysis. We report on implementations of local algorithms for feature extractio n as part of triggering, using the detectors of the proposed ATLAS exp eriment as a model. The algorithms were implemented for a decision fre quency of 100 kHz, on different data-driven programmable devices based on structures of field-programmable gate arrays and memories. The imp lementations were demonstrated at full speed with emulated input, and were also integrated into a prototype detector running in a test beam at CERN, in June 1994.