INVESTIGATION OF A VLSI NEURAL-NETWORK CHIP AS PART OF A SECONDARY VERTEX TRIGGER

An analog VLSI neural network chip (ETANN) has been trained to detect secondary vertices in simulated data for a fixed target heavy flavour production experiment. The detector response and associative memory tr ack finding were modelled by a simulation, but the vertex detection wa s performed in hardware by the neural network chip and requires only a few microseconds per event. The chip correctly tags 30% of the heavy flavour events while rejecting 99% of the background, and is thus well adapted for secondary vertex triggering applications. A general purpo se VME module for interfacing the ETANN to experiments, equipped with ADC/DAC circuits and a 68070 CPU, is also presented.