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Digital detectors based on complementary metaloxide-semiconductors (CMOS) active pixel sensor (APS) technology have been introduced recently in many scientific applications. This work is focused on the X-ray performance evaluation of a novel CMOS APS detector in low energy medical imaging applications using monochromatic synchrotron radiation (i.e. 17-35 keV), which also allows studying how the performance varies with energy. The CMOS sensor was coupled to a Thallium-activated structured cesium iodide (CsI:Tl) scintillator and the detector's X-ray performance evaluation was carried out in terms of sensitivity, presampling modulation transfer function (pMTF), normalized noise power spectrum (NNPS) and the resulting detective quantum efficiency (DQE). A Monte Carlo simulation was used to validate the experimentally measured low frequency DQE. Finally, the effect of iodine's secondary generated K-fluorescence X-rays on pMTF and DQE results was evaluated. Good agreement (within 5%) was observed between the Monte Carlo and experimentally measured low frequency DQE results. A CMOS APS detector was characterized for the first time over a wide range of low energies covering the mammographic spectra. The detector's performance is limited mainly by the detectability of the scintillator. Finally, we show that the current data could be used to calculate the detector's pMTF, NNPS and DQE for any mammographic spectral shape within the investigated energies.

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Synchrotron radiation microtomography is an elegant nondestructive imaging technique to investigate the microstructural properties of porous cellular matrices like the green and roasted coffee beans. The quantitative analysis of the resulting 2D and 3D images allows a more comprehensive and objective characterization of the sample under investigation as a whole or of extracted Volumes-of-Interest in the bean. This imaging technique could have a major role in understanding the effects of roasting process conditions on the microstructural properties of the bean.

Use of Zn sponges has been recently proposed as an effective means of limiting the shape change and dendrite formation issues, affecting the anodes of electrically rechargeable Zn-based batteries. This paper contributes to this field of research with in situ X-ray computed microtomography (XCMT) monitoring of the morphological and chemical changes undergone by Zn-sponge anodes during electrochemical cycling. Starting from a pristine anode, fabricated in the discharged state, this was first charged and then subjected to a representative series of charge–discharge sequences and, in correspondence, it was studied by XCMT in order to determine (i) the volume fractions of Zn and ZnO, porosity, and their space arrangement and (ii) the degree of connectivity of the elemental Zn framework. Good stability of the metal framework, reversibility of the Zn and ZnO phases, and their space distribution, with a limited alteration of the pore structure, were observed over more than 60 charge–discharge cycles.