Development of active pixel vertex detectors for high luminosity particle physics applications

Pixel vertex detectors are presently under consideration for use in future heavy ion experiments and for experiments at the future LHC and SSC * hadron collider, where they might contain more than 1 m2 of active area, with more than 108 individually-addressable pixel elements. The readout electronics for each pixel - amplifier/shaper, comparator and storage element - may be integrated into the detector wafer itself, or be bonded to it in a ''hybrid'' assembly. Both hybrid and monolithic detectors are under development in parallel programs in the United States and Europe, focussed on the implementation of radiation tolerant detectors and electronics, with high speed, time-referenced, sparsified readout of only the pixels containing information for triggered events. Such ''smart'' or ''active'' readout is particularly demanding, requiring ''data-driven'' architectures. The recent development and present status of these detectors is reviewed. Their implementation in future high energy physics experiments is discussed. ((orig.))