A cellular automaton to filter events in a high energy physics discrete calorimeter

In this paper the noise-filtering capabilities of a cellular automaton are studied. The tests have been performed on 4 GeV pion experimental events taken with a Silicon Tungsten tracking calorimeter at CERN PS. Particle interaction with the material of the calorimeter can produce straight tracks or hadronic showers. The evolution rules devised for the CA have therefore to reckon with these different topologies in order to remove noise and restore interrupted tracks. At the same time, strips hit by particles should be affected as little as possible. The distributions of some discriminating parameters are compared with Monte Carlo data before and after being filtered by the automaton and the agreement is shown to improve. The Cellular Automaton constitutes a simple (Boolean logic) and fast (with possible on-line applications) filter. Its applications range from particle discrimination to track restoration in time-worn detectors.