Silicon Devices for Charged-Particle Track and Vertex Detection

The discovery of relatively long-lived charmed particles in 1976 prompted physicists to reexamine the superb properties of semiconductor detectors for energy and position measurements. In the early 1980s the first silicon strip detectors were successfully used as charged-particle track and vertex detectors to filter the decays of charmed particles out of the huge debris of hadrons produced in proton-nucleus interactions. The successful application of these devices soon led to proposals to use them also in colliding beam experiments. These initiatives resulted in an intense re­ search and development program that focused on custom-designed, very highly integrated readout electronics and low-mass but high-stability support structures and that sought to characterize the damaging effects of ionizing radiation to be encountered in high-rate accelerators. In this article we first outline the basics of semiconductor physics and then give a detailed description of silicon strip detectors, pixel devices, and novel de­ tector structures currently under development. The damaging effects of ionizing radiation on both the detecting elements and the readout electronics are briefly ad­ dressed. The problems encountered in moving from a single semiconductor detec­ tor element to a large detector system to be used for research in elementary particle physics are illustrated by the discussion of two large-scale experimental applica­ tions: a state-of-the-art fixed-target experiment and a colliding-beam experiment.