Results of a 100 MHz FADC System Built in FASTBUS Used by the UA2 Vertex Detector

摘要

The drift chambers of the UA2 vertex detector were equipped with a FASTBUS-based, 100 MHz FADC system for the 1985 run of the CERN anti p p collider. This was the first large-scale use of such a system. Pulse shaping and online zero suppression were used to reduce the total amount of data produced by the system. A substantial improvement with respect to the previously used system in the two-track separation was obtained with no loss in precision for the reconstructed coordinates. The drift time information was used to reconstruct transverse coordinates with a precision of approx.145 mu m (rms). The longitudinal coordinates were derived from charge division with a precision of better than 1% of the wire length. The two-track separation was 2.5 mm with an efficiency of 90%. (ERA citation 11:028144)