Semiconductor detectors for 2D X-ray imaging

Semiconductor nuclear radiation detectors are nowadays of current use for high-resolution spectrometry in a number of fields, including those involving X-ray measurements. The significant advances achieved during the last 10 years in materials properties, detector characteristics, and high-quality electronic systems, now make it possible to go one step further and to build 2D X-ray imaging systems based on semiconductor detectors. It is the aim of this paper to present the state-of-the-art of X-ray imaging systems based on such devices. First the basic principles involved will be presented. The main requirements (detector size, spatial resolution, pixel number, dynamics, counting rate, etc.) and limitations (physical and experimental limitations), with respect to the applications envisaged (material science, medical or industrial imaging) will be discussed. The major properties of the semiconductors of interest for such applications will be briefly summarized. Then the working principles and main characteristics of existing systems based on various semiconductor materials and devices will be reviewed and compared to those of conventional X-ray imagers. Finally, possible evolutions will be discussed in terms of new detector materials and new semiconductor devices, taking into account the increasing potential of microelectronics technology.