A CDU-based data acquisition system for the energy spectrometer at the Standard Linear Collider

The authors discuss the design and performance of a system using the calorimetry data unit (a 32-channel multisample analog integrated circuit) to read out the charge ejected by secondary emission of a synchrotron beam from wires lying in its path. The wires comprise the wire-imaging synchrotron radiation detector in the SLC (Stanford Linear Collider) extraction-line spectrometer. The primary module in the system is a board containing 24 channels of charge-sensitive amplification, shaping, sampling, multiplexing, and digitization. This board also provides a fast analog measure of the charge distribution across the wires. The time between the beam crossing and completion of data acquisition into CAMAC is shown to be 1.1. ms, providing beam pulse energy measurements at the maximum accelerator repetition rate of 180 Hz for every event logged by the Mark II detector