ABSTRACT
Photon-counting imagers have appeared recently in high-energy physics experiments. In these experiments, localization of ionizing particles has been done for several years by multiwire proportional chambers (MWPCs) with many variations (drift
11.1 Introduction .................................................................................................. 237 11.2 From High-Energy Physics to X-Ray Imagers ............................................. 238
11.2.1 Silicon Detector Developments for Microvertex Detectors in High-Energy Experiments ................................................................ 238
11.2.2 From High-Energy Particle Physics Detectors to X-Ray Cameras ............................................................................................ 241
11.3 Hybrid Pixel Detectors .................................................................................242 11.3.1 Sensors ..............................................................................................242 11.3.2 Front-End Electronics ....................................................................... 243 11.3.3 The Bump-Bonding Technique ........................................................ 243
11.4 XPAD, a Hybrid Pixel Detector .................................................................... 243 11.4.1 The XPAD1 and XPAD2 Chips........................................................244 11.4.2 The XPAD3 Chip ............................................................................. 247
11.5 Applications of X-Ray Imagers .................................................................... 253 11.5.1 Crystallography Application in Material Sciences ........................... 253 11.5.2 Biomedical Application: Computer Tomography ............................. 257
11.6 From 2D to 3D Approach: A New Hybrid Trend ......................................... 259 References ..............................................................................................................260
chambers, TPC, etc.). For vertex applications, these detectors have been progressively replaced by silicon sensors, rst arranged in microstrip detectors, and more recently (1997) in hybrid pixel detectors. These detectors are extensively used in the big detectors of the Large Hadron Collider (LHC) at the European Organization for Nuclear Research (CERN, Geneva, Switzerland). Some of these detectors, adapted to photon detection, have appeared more recently to cover other areas, such as medical imaging or crystallography experiments.
