MONICA - an on-line track following microprocessor in high energy physics experiments

In the storage ring experiments at the PETRA accelerator, large cylindrical detectors with thousands of channels are used. The maximum event rate is 500 000 per second, i.e. effective preprocessing is required. In the TASSO detector this is achieved in two steps: A fast trigger system is able to make within 1 microsecond a decision, whether it is a useful event or not. A positive decision starts an on-line track-following ECL computer together with fast associative memories and table look-up. It is a microprogrammed on-line track analyzer called MONICA, which follows up to 10 tracks within 1 millisecond and calculates the coordinates in the R,phi-plane. CAMAC equipment is used for the input of raw data and the output of the calculated track coordinates, speed of the system is ensured by the computer. An outline of the algorithm used and the features of MONICA are given. As far as we know MONICA is the first running on-line track following free programmable microporcessor used in storage ring experiments. (orig.)