Development of a PCI Express Based Readout Electronics for the XPAD3 X-Ray Photon Counting Image

International audienceXPAD3 is a large surface X-ray photon counting imager with high count rates, large counter dynamics and very fast data readout. Data are readout in parallel by a PCI Express interface using DMA transfer. The readout frame rate of the complete detector comprising 0.5 MPixels amounts to 500 images per second without dead-time

CFD methods and Flory-Huggins theory utilization in mathematical modeling of water-ethanol pervaporation process

Rozdział mieszaniny woda-etanol ma duże znaczenie dla wielu gałęzi przemysłu. Powszechnie stosowane techniki rozdziału tego układu posiadają szereg wad. Jedną z alternatyw jest proces perwaporacji. W celu upowszechnienia stosowalności perwaporacji podjęto próbę modelowania wspomnianego układu. W tym celu wykorzystano model Flory-Hugginsa, I prawo Ficka oraz metody CFD. Otrzymane wyniki pozwoliły ocenić wpływ polaryzacji na transport masy w perwaporacji.Separation of water-ethanol mixture is of great significance for many branches of industry. Separation techniques commonly used to separate above-mentioned mixture have many drawbacks. Pervaporation is one of alternatives. To make this process more applicable a mathematical model was created. The Flory-Huggins theory, first Fick's law and CFD methods were used in this model. Modeling results enable one to asses the influence of concentration polarization on mass transfer in pervaporation

Characterisation of the UFXC32k hybrid pixel detector for time-resolved pump-probe diffraction experiments at Synchrotron SOLEIL

International audienceThe experimental set-up for time-resolved studies of ultra-fast photo-induced structural dynamics at the Synchrotron SOLEIL is based on a general pump-probe scheme that has been developed and implemented on the CRISTAL hard X-ray diffraction beamline [1,2]. In a so-called pump-probe cycle, the sample is excited with an ultra-short laser pulse of ≈40 fs duration (the pump), and induced changes in its atomic structure are studied by measuring, with a precisely controlled delay, a diffraction pattern from a single pulse of synchrotron radiation (the probe) with a 2-D pixel detector. An improvement to the classical scheme is proposed, where the sample's response is probed at two different delays after each laser excitation. The first measurement at short delays allows studying the photo-induced dynamics. The second one is a reference measurement taken after sample's relaxation, which permits detection of drifts in the experimental conditions (e.g. beam misalignment, sample degradation). A hybrid pixel detector with a very fast readout time, a high dynamic range and extended linearity was tested to achieve the experiment objectives. In this paper, the first results obtained with the UFXC32k single photon counting detector are presented

Thin Films Characterization Using Fast Data Acquisition at DiffAbs Beamline (Synchrotron SOLEIL)

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Thin Films Characterization Using Fast Data Acquisition at DiffAbs Beamline (SOLEIL)

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Study of the X-ray scattering in the silicon and CdTe XPAD

The XPAD3, a photon counting hybrid pixel detector developed in collaboration by SOLEIL Synchrotron, the Institut Néel and the Centre de Physique des Particules de Marseille (CPPM) [1], is now successfully used for a large variety of X-ray experiments on third generation synchrotron light sources [2]. Several 7.3 cm x 12.5 cm imagers composed of 8 silicon modules (7 chips per module, 9600 pixel of 130μm side per chip) are routinely used on different synchrotron beamlines at Soleil and on the CRG beamline D2AM at ESRF. Detector performances such as noiseless detection, high dynamic (27 bits) and fast framing rate (640 fps) have opened up the possibility of new or improved types of measurements. Nevertheless, above 15 keV, besides the loss of efficiency [2], the X-ray scattering in silicon sensor and the material located behind significantly increases the shape and the width of thepoint-spread function at 0.01% of the maximum. This effect prevents the study of low intensity phenomena such as diffuse scattering, which would be observed at the foot of theBragg peak and theoretically measurable with the large dynamic of the detector. This effect has been measured at different energies with monochromatic synchrotron beam (on CRISTAL and METROLOGIE Soleil beamlines) on a mono module Silicon XPAD and then compared with a Quad CdTe XPAD prototype (cf. figure 1). The results, which will be presented, demonstrate the superiority of the high Z sensor and push the investigation of the CdTe as a material sensor even at mid energy

Thin Films Characterization Using Fast Data Acquisition at DiffAbs Beamline (Synchrotron SOLEIL)

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Characterization of the imaging performance of a micro-CT system based on the photon counting XPAD3/Si hybrid pixel detectors

International audienceWe characterize the imaging performance of the micro computed tomography (micro-CT) prototype PIXSCAN equipped with an x-ray photon counting camera based on XPAD3/Si hybrid pixel detectors. The camera, which is composed of eight distinctive horizontal modules, permits the performance of whole-body mouse scans. Photon counting supplied by hybrid pixels guarantees acquisitions at a Poisson noise level exclusively determined by the detected photon statistics. First, we characterize the performance of the imaging system while assessing its linearity, noise, spatial resolution and low contrast detectability estimated from scans of appropriate phantoms. Then, we show CT images of mice data acquired either in vivo or post mortem, without or with an injection of iodine as a contrast agent. Although hybrid pixels guarantee a minimal noise to the images, the limited detection efficiency of Si sensors impairs detected photon statistics and therefore the improvement in contrast-to-noise ratio for standard tomographic imaging. Indeed, the most innovative potential of the PIXSCAN prototype is its capacity to perform spectral tomographic imaging and fast dynamic imaging. The first is thanks to the possibility of setting an energy threshold on the detected photons, and the second is thanks to its fast acquisition rate (till 500 images/s). We present some examples of these imaging methods applied to mice and discuss their main limiting factors