SOUDAN 2 DATA ACQUISITION AND TRIGGER ELECTRONICS.

Data acquisition and trigger electronics for the Soudan 2 nucleon decay experiment are described. The 1100-ton Soudan 2 detector is read out by 16K anode wires and 32K cathode strips. Preamps from each wire or strip are bused together in groups of 8 to reduce the number of ADC channels. The resulting 6144 channels of ionization signal are flash-digitized every 150 ns and stored in RAM. The raw data hit patterns are continually compared with programmable trigger multiplicity and adjacency conditions. The data acquisition process is managed in a system of 24 parallel crates, each containing an Intel 8086 microprocessors. The microprocessors supervise a pipelined data compactor and allow transfer of the compacted data via CAMAC to the host computer. They also manage the local trigger conditions and can perform some parallel processing of the data.