An overall MWPC-readout system based on chamber mounted ASICs

At the Julich Cooler Synchrotron, COSY, the magnetic spectrometer ANKE (Apparatus for Studies of Nucleon and Kaon Ejectils) is installed. Reaction products emitted by an internal target in the forward direction are measured. About 11000 channels are read out. This requirement justified the design of a VLSI based readout system. For this, an analog chip (RAL 118)-a low power high speed eight channel amplifier and discriminator-is used. Digital delay, zero suppression and address encoding are performed by the digital chip RAL 111 from the Rutherford Appleton Laboratory. A scalable and flexible array of chamber mounted front end boards may be adapted to instrument detectors of any size. Readout is performed by serializing hit addresses over a high speed optical link to a CAMAC readout module which serves for additional data reduction, subevent building and a number of test functions. Furthermore, subevent data are transferred using a front panel ECLbus (FERAbus*) to a crate controller with PCI-interface. An industrial PC with diskless UNIX-compatible operating system (NetBSD) is responsible for controlling the CAMAC crate, processing the event data and connecting to a central event builder.