The Front-End Electronics

Abstract

One of the biggest challenges in the construction of a pixel detector is the design of suited readout chips with several thousand electronic channels. These pixel chips contain a regular arrangement of pixel unit cells, each one serving one sensor pixel connected through a bump-bond connection and, in addition, on-chip circuitry by which hit information is transported to the bottom of each chip from where it can be transmitted out. The pixel unit cells must be as small as possible because their area dictates the sensor pixel size and therefore the spatial resolution. While dissipating typically well below 100 μW, every pixel circuit must provide a low noise amplification of the sensor charge, hit discrimination, and a readout architecture adapted to the application. A sufficient speed of the analog chain and the digital section, a well-defined threshold, and possibly a high-radiation hardness must be guaranteed. This chapter discusses the various requirements and presents solutions to the above-mentioned challenges. Various existing readout architectures for experiments in particle physics and biomedicine are described.