XPAD: pixel detector for material sciences

Currently available 2D detectors do not make full use of the high flux and high brilliance of third generation synchrotron sources. The XPAD prototype, using active pixels, has been developed to fulfil the needs of materials science scattering experiments. At the time, its prototype is build of eight modules of eight chips. The threshold calibration of /spl ap/4 10/sup 4/ pixels is discussed. Applications to powder diffraction or SAXS experiments prove that it allows to record high quality data

Bipolar low-power operational transresistance amplifier based on first generation current conveyor

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A pixel detector with large dynamic range for high photon counting rates

In this paper, results obtained from a prototype photon counting detector are presented. The pixel size is 330 ìm x 330 ìm for a total area of 16 ìm x 40 mm. The detector works at room temperature and its dynamic response ranges from 0.01 up to 106 photons pixel-1 s-1. An energy resolution of about 1.5 keV has been measured. Very encouraging small-angle X-ray scattering (SAXS) and diffraction patterns were obtained, demonstrating the success of the prototype. Plans for future developments based on this study are presented

Pixel detectors: New detectors for X-ray scattering

The progress in micro electronic and the avaibility to develop custom electronic chips allow to realize a new kind of 2D detectors, the pixel detectors. They can be considered as an array of photon counters with a size of some tenth of millimeters. They allow to obtain images with a higher dynamical range allowing to study complex diffraction systems including weak diffusion.Les progrès de la microélectronique et la possibilité de développer des circuits électroniques dédiés ont rendu possible le developpernent de nouveaux détecteurs 2D, les détecteurs à pixels. Ils peuvent être considérés comme un pavage de compteurs de photons d'une taille de quelques dixièmes de millimètres. Ils permettent d'obtenir des images avec une plus grande dynamique afin d'étudier des systèmes mélant une diffraction complexe et une diffusion faible

The hybrid pixel single photon counting detector XPAD

International audienceThe XPAD detector is a 2D X-ray imager based on hybrid pixel technology, gathering 38400 pixels on a surface of 68*68 mm(2). It is a photon counting detector, with low noise, wide dynamic range and high speed read out, which make it particularly suitable for third generation synchrotron applications, such as diffraction, small angle X-ray scattering or macro-molecular crystallography, but also for small animal imaging. High resolution powder diffraction data and in situ scattering data of crystallization of liquid oxides are presented to illustrate the properties of this detector, resulting in a significant gain in data acquisition time and a capability to follow fast kinetics in real time experiments. The characteristics of the future generation of XPAD detector, which will be available in 2007, are also presented

Application of hybrid pixel detector to powder diffraction.

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PIXSCAN: Pixel Detector CT-Scanner for Small Animal Imaging

articleThe PIXSCAN is a small animal CT-scanner based on hybrid pixel detectors. These detectors provide very large dynamic range of photons counting at very low detector noise. They also provide high counting rates with fast image readout. Detection efficiency can be optimized by selecting the sensor medium according to the working energy range. Indeed, the use of CdTe allows a detection efficiency of 100% up to 50 keV. Altogether these characteristics are expected to improve the contrast of the CT-scanner, especially for soft tissues, and to reduce both the scan duration and the absorbed dose. A proof of principle has been performed by assembling into a PIXSCAN-XPAD2 prototype the photon counting pixel detector initially built for detection of X-ray synchrotron radiations. Despite the relatively large pixel size of this detector (330×330 μm2), we can present three-dimensional tomographic reconstruction of mice at good contrast and spatial resolution. A new photon counting chip (XPAD3) is designed in sub-micronique technology to achieve 130×130 μm2 pixels. This improved circuit has been equipped with an energy selection circuit to act as a band-pass emission filter. Furthermore, the PIXSCAN-XPAD3 hybrid pixel detectors will be combined with the Lausanne ClearPET scanner demonstrator. CT image reconstruction in this non-conventional geometry is under study for this purpose