A computer program named ANKAphase is presented that processes X-ray inline phase-contrast radiographs by reconstructing the projected thickness of the object(s) imaged. The program uses a single-distance non-iterative phase-retrieval algorithm described by David Paganin et al. [(2002), J. Microsc. 206, 33-40]. Allowing for non-negligible absorption in the sample, this method is strictly valid only for monochromatic illumination and single-material objects but tolerates deviations from these conditions, especially polychromaticity. ANKAphase is designed to be applied to tomography data (although it does not perform tomographic reconstruction itself). It can process series of images and perform flat-field and dark-field correction. Written in Java, ANKAphase has an intuitive graphical user interface and can be run either as a stand-alone application or as a plugin to ImageJ, a widely used scientific image-processing program. A description of ANKAphase is given and example applications are shown.

We report an experimental proof of principle for ghost imaging in the hard x-ray energy range. We used a synchrotron x-ray beam that was split using a thin crystal in Laue diffraction geometry. With an ultra-fast imaging camera, we were able to image x-rays generated by isolated electron bunches. At this time scale, the shot noise of the synchrotron emission process is measurable as speckles, leading to speckle correlation between the two beams. The integrated transmitted intensity from a sample located in the first beam was correlated with the spatially resolved intensity measured in the second, empty, beam to retrieve the shadow of the sample. The demonstration of ghost imaging with hard x-rays may open the way to protocols to reduce radiation damage in medical imaging and in non-destructive structural characterization using Free Electron Lasers.Ghost imaging, in its basic form, is the technique of indirectly imaging a sample by using the correlation between the intensity recorded at two detectors illuminated by spatially separated correlated beams [1]. A bucket detector measures the total intensity transmitted (or scattered) by a sample, placed in one of the beams. The sample image is then retrieved by correlating the output of the bucket detector with a pixel array detector located in the other beam, namely the one that has not directly interacted with the sample. Initially demonstrated with entangled photon pairs [2], ghost imaging was subsequently performed using correlation between classical coherent light beams [3]. The protocol was shown to be very robust, leading to experimental studies on ghost imaging using pseudo-thermal light [4][5][6], true thermal sources [7], and eventually computational ghost imaging [8], where a computer-controlled spatial light modulator generates a series of known illuminating fields, altogether removing the need for imaging the empty beam. Of relevance for this paper is also a very recent demonstration of Fourier transform ghost imaging using speckle fields generated with partially coherent synchrotron x-rays [9]. At the heart of thermal ghost imaging is the speckle correlation in the intensity fluctuations of the illuminating beam. The speckles can be produced either by nearfield diffraction of a coherent beam by a slowly moving diffracting object [4-6, 9], or taking advantage of the natural fluctuations of true thermal light [7], as in the Hanbury Brown-Twiss (intensity) interferometer [10]. In this Letter we use the latter mechanism to produce the first proof of principle demonstration of hard x-ray direct ghost imaging using synchrotron emission from an undulator in a third generation synchrotron storage ring. Synchrotron emission from an ultra-relativistic electron bunch provides a natural thermal source of hard x-rays. Intensity correlation x-ray experiments, proposed as far back as 1975 [11] (see also [12]), were employed several times for coherence characterization of synchrotron [13][14][15] and x-ray Free Electron Laser (FEL) [16] beams. To date though, x-ray spec...

a Lithium-ion batteries are being used in increasingly demanding applications where safety and reliability are of utmost importance. Thermal runaway presents the greatest safety hazard, and needs to be fully understood in order to progress towards safer cell and battery designs. Here, we demonstrate the application of an internal short circuiting device for controlled, on-demand, initiation of thermal runaway. Through its use, the location and timing of thermal runaway initiation is pre-determined, allowing analysis of the nucleation and propagation of failure within 18 650 cells through the use of high-speed X-ray imaging at 2000 frames per second. The cause of unfavourable occurrences such as sidewall rupture, cell bursting, and cell-to-cell propagation within modules is elucidated, and steps towards improved safety of 18 650 cells and batteries are discussed. Broader contextFrom portable electronics to grid-scale storage, high energy density Li-ion batteries are ubiquitous in today's society. Such cells can and do fail, sometimes catastrophically, releasing large amounts of energy. To facilitate safer and more reliable cell designs, the importance of understanding failure mechanisms of Li-ion cells is widely recognised. Here, we demonstrate the application of a novel device that is capable of generating an internal short circuit within commercial cell designs, on-demand, and at a predetermined location. This enables us to test more effectively the ability of safety devices of cells and modules to withstand 'worst-case' failure scenarios. By combining the use of this device with high-speed X-ray imaging at 2000 frames per second, we characterise for the first time the initiation and propagation of thermal runaway from a known location within a Li-ion cell. The insights achieved in this study are expected to guide the design and development of safer and more reliable Li-ion cells.

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As the energy density of lithium‐ion cells and batteries increases, controlling the outcomes of thermal runaway becomes more challenging. If the high rate of gas generation during thermal runaway is not adequately vented, commercial cell designs can rupture and explode, presenting serious safety concerns. Here, ultra‐high‐speed synchrotron X‐ray imaging is used at >20 000 frames per second to characterize the venting processes of six different 18650 cell designs undergoing thermal runaway. For the first time, the mechanisms that lead to the most catastrophic type of cell failure, rupture, and explosion are identified and elucidated in detail. The practical application of the technique is highlighted by evaluating a novel 18650 cell design with a second vent at the base, which is shown to avoid the critical stages that lead to rupture. The insights yielded in this study shed new light on battery failure and are expected to guide the development of safer commercial cell designs.

Significant progress has been made in understanding the interaction between mineral precursors and organic components leading to material formation and structuring in biomineralizing systems. The mesostructure of biological materials, such as the outer calcitic shell of molluscs, is characterized by many parameters and the question arises as to what extent they all are, or need to be, controlled biologically. Here, we analyse the three-dimensional structure of the calcite-based prismatic layer of Pinna nobilis, the giant Mediterranean fan mussel, using high-resolution synchrotron-based microtomography. We show that the evolution of the layer is statistically self-similar and, remarkably, its morphology and mesostructure can be fully predicted using classical materials science theories for normal grain growth. These findings are a fundamental step in understanding the constraints that dictate the shape of these biogenic minerals and shed light on how biological organisms make use of thermodynamics to generate complex morphologies.

Mechanical abuse of lithium-ion batteries is widely used during testing to induce thermal runaway, characterize associated risks, and expose cell and module vulnerabilities. However, the repeatability of puncture or 'nail penetration' tests is a key issue as there is often a high degree of variability in the resulting thermal runaway process. In this work, the failure mechanisms of 18650 cells punctured at different locations and orientations are characterized with respect to their internal structural degradation, and both their internal and surface temperature, all of which are monitored in real time. The initiation and propagation of thermal runaway is visualized via high-speed synchrotron X-ray radiography at 2000 frames per second, and the surface and internal temperatures are recorded via infrared imaging and a thermocouple embedded in the tip of the penetrating nail, respectively. The influence of the nail, as well as how and where it penetrates the cell, on the initiation and propagation of thermal runaway is described and the suitability of this test method for representing in-field failures is discussed.