A multichannel discriminator system for silicon strip detector readout

Up to 9216 fast discriminators are required for processing signals of the Fermilab silicon strip detector preamplifiers in experiment E789. Signals exceeding a preset discriminator threshold voltage are first stored in a clocked latch and then delayed by three 19-ns clock cycles with a shift resister. Discriminators are organized in 75 identical 128-channel subsystems. Each has four 32-channel PC boards housed in a signal routing motherboard. Eight 16-channel line driver boards transfer events from the motherboard through cables to the remote processing electronics. Three subsystems fit into the frame of a standard CAMAC crate. The authors describe the design considerations of the system and its performance, based on several months of testing the completed system.<
>