General lessons from the SLD vertex detector

This paper describes the design, construction, and initial operation of the SLD Vertex Detector, the first device to employ charge coupled devices (CCDS) on a large scale in a high energy physics experiment. The Venex Detector comprises 480 CCDS, with a total of 120 Mpixels. Each pixel functions as an independent particle detecting element, providing space point measurements of charged particle tracks with a typical precision of 5 μm in each coordinate. The CCDs are arranged in four concentric cylinders just outside the beam pipe which surrounds the e+e- collision point of the SLAC Linear Collider (SLC). The Vertex Detector is a powerful tool for distinguishing secondary vertex tracks, produced by decay in flight of heavy flavour hadrons or tau leptons, from tracks produced at the primary event vertex. Because the colliding beam environment imposes severe constraints on the design of such a detector, a six year R ampersand D programme was needed to develop solutions to a number of problems. The requirements include a low-mass structure (to minimize multiple scattering) both for mechanical support and to provide signal paths for the CCDS; operation at low temperature with a high degree of mechanical stability; and relatively high speed CCD readout, signal processing, and data sparsification. The lessons learned through the long R ampersand D period should be useful for the construction of large arrays of CCDs or smart pixel devices in the future, in a number of areas of science and technology