arXiv subjects

Silvia Cipiccia

Publications and source records attributed to Silvia Cipiccia.

14 recordsLinked to original sources

arXiv2026

Matching Trace Element Distribution to Mineralogical Phases in Ancient Biotechnology-Derived Metallic Salts: a Multimodal Analysis

Conventional X-ray fluorescence (XRF) and X-ray diffraction (XRD) analysis applied to the investigation of ancient metal salts used as pigments and/or therapeutics provide bulk average compositions in two stand-alone data sets; however, major elements aside, these two sets cannot inform on the spatial distribution of one with respect to the other. To address this issue, we present here a multimodal approach incorporating spatially resolved XRF, XRD and nanoscale X-ray imaging applied to the analysis of archaeological and experimental samples of synthetic lead carbonate (PbCO3 - Greek psimythion); psimythion was used in antiquity as a cosmetic and/or a therapeutic for external applications. The experimental sample was produced according to a well-documented recipe dated to the 4th century BCE. In this paper we demonstrate that by using a multimodal approach we can confidently assign trace elements to individual crystalline or to infer the existence of non-crystalline phases. Although the assignment of an element to a phase (i.e. the location) is now possible, the origin underlying it (i.e. the mechanism) is not always clear. Trace elements do not 'control' chemical/mineralogical composition, but they can influence it. Our approach is particularly suited to following changes in the artefact's chemical/mineralogical profile, from its manufacture, to use and burial, to excavation and conservation.

physics.app-ph↗

arXiv2026

Material identification using laboratory X-ray beam tracking: quantitativeness and signal-to-noise ratio requirements

Simultaneous structural and elemental characterisation of a specimen in a non-destructive manner is an instrumental approach with applications in a variety of fields including energy materials, cultural heritage and life sciences. This is routinely performed at synchrotron facilities, e.g. by combining X-ray imaging and X-ray fluorescence. In this work we describe an approach based on a monochromatic implementation of X-ray beam tracking (XBT), a multimodal imaging technique compatible with standard laboratory sources. Monochromatic XBT gives simultaneous access to quantitative absorption and phase properties of the sample, which are related to the atomic number and the electron density respectively: their combination allows for material discrimination. Here we focus on investigating the effect of the signal-to noise ratio on the quantitativeness of the results, hence on the elemental identification. We present an XBT experiment performed using a standard X-ray laboratory source to identify the composition of three different test samples made out of Ag, Fe and Cu. These specific materials were selected as relevant to archaeological studies e.g. when specimen buried for centuries are in contact with the surrounding soil containing traces of these metals. We review the results, current limitations and provide guidance for future developments for structural and elemental characterisation in a laboratory setting.

physics.app-ph↗

arXiv2025

Quantitative phase nano-imaging with a laboratory source

Investigating the structure of matter at the nanoscale non destructively is a key capability enabled by X-ray imaging. One of the most powerful nano-imaging methods is X-ray ptychography, a coherent diffraction imaging technique that has become the go-to method at synchrotron facilities for applications ranging from brain imaging to battery materials. However, the requirements in terms of X-ray beam quality have limited its use to large synchrotron facilities and, to date, only one attempt has been made to translate the technique to a small-scale laboratory. To unleash the power of this technique to the broad user community of laboratory X-ray sources, there are outstanding questions to answer including whether the quantitativeness of the information is preserved in a laboratory despite the drastic decrease in X-ray flux of several orders of magnitude, with respect to synchrotron instruments. In this study not only we demonstrate that the quantitativeness of X-ray ptychography is preserved in a laboratory setting, but we also apply the method to the imaging of a brain tissue phantom. Finally, we describe the current challenges and limitations, and we set the basis for further development and future directions of quantitative nano-imaging with laboratory X-ray sources.

physics.comp-ph↗

arXiv2025

Laboratory-based x-ray microtomography with directional dark-field sensitivity

We demonstrate dark-field x-ray microtomography in a compact, laboratory-based system capable of resolving attenuation, phase, and anisotropic scattering signals with micrometer-scale resolution across centimetre-scale samples. The method is based on two-directional beam tracking (2DBT), which requires only a single optical element and is compatible with standard x-ray sources and detectors. We validate the system's capabilities through imaging of a custom-built phantom, a fibre-reinforced composite and ex-vivo biological tissues, including a bovine intervertebral disc, a rat heart, and a porcine meniscus. The results show that dark-field tomography provides complementary information to attenuation as well as to phase tomography, by revealing sub-resolution features such as fibre orientation and microstructural heterogeneity at length scales that are well below the voxel size. A key element of our system is its sensitivity to scattering along two orthogonal directions in the image plane, enabling the measurement of scattering anisotropy with a single exposure. As well as simple and robust, our approach is sensitive and precise. These findings demonstrate the potential of 2DBT for non-destructive and three-dimensional structural characterisation of samples and materials in engineering, materials science and biomedical applications.

physics.optics↗

arXiv2025

Electron volt energy resolution with ptychography using a broadband continuum spectrum

Ptychography is a scanning coherent diffraction imaging technique successfully applied in the electron, visible and x-ray regimes. One of the distinct features of ptychography with respect to other coherent diffraction techniques is its capability of dealing with partial spatial and temporal coherence via the reconstruction algorithm. Here we focus on the temporal and clarify theoretically and with simulations the constraints which affect the energy resolution limits of the ptychographic algorithms. Based on this, we design and perform simulations for a broadband ptychography in the hard x-ray regime, which enables an energy resolution down to 1 eV. We benchmark the simulations against experimental ptychographic data from a nickel test sample, by extracting the x-ray absorption near edge spectrum with energy resolution of 5 eV using a continuum spectrum of 20 eV bandwidth. We review the results, discuss the limitations, and provide guidelines for future broadband ptychography experiments, its prospective applications and potential impact on achieving diffraction limited resolutions.

physics.app-ph↗

arXiv2025

Optics for broadband x-ray ptychography

In conventional x-ray ptychography, diffraction data is collected by scanning a sample through a monochromatic, and spatially coherent, x-ray beam. A high-resolution image is then retrieved using an iterative algorithm. Combined with a scan of the incident photon energy, it is also possible to access chemical and elemental information. Although powerful, the high brilliance required currently constrains the method to 3rd and 4th generation synchrotron sources and long scanning times. An alternative approach is to use a broadband illumination in combination with an energy resolving detector. These detectors record the data in a series of energy channels simultaneously, creating a stack of coherent data suitable for a ptychographic reconstruction. This approach promises to unlock the full power of the radiation source and provide spectral imaging at a higher rate and in a single acquisition. However, these detectors currently saturate well below reaching the flux rates produced at synchrotrons, which is preventing the uptake of this approach. Furthermore, current monochromatic synchrotron setups typically employ Fresnel zone plates for pre-sample focusing due to their stability, flexibility, and affordability, but these diffractive optics limit the spectral bandwidth that the setup can accept. In this article, we analyze the problem and consider alternative optics that can both maximize the total photon detection rates and broaden the tolerable bandwidth. Broadband x-ray ptychography has the potential to dramatically reduce data collection times at synchrotron sources, but also to harness the full power of lower brilliance sources and transition x-ray ptychography into a laboratory technique.

physics.optics↗

arXiv2025

Revealing Nanoscale Ni-Oxidation State Variations in Single-Crystal NMC811 via 2D and 3D Spectro-Ptychography

Enabling lithium (Li)-ion batteries with higher energy densities, longer cycle life, and lower costs will underpin the widespread electrification of the transportation and large-scale energy storage industries. Nickel (Ni)-rich layered oxide cathodes, such as LiNi$_{x}$Mn$_{y}$Co$_{z}$O$_{2}$ (NMC, x > 0.8), have gained popularity due to their high specific capacities and lower cobalt content. However, the standard polycrystalline morphology suffers from accelerated degradation at voltages above 4.2 V versus graphite, due to its increased mechanical and chemical instability. Single-crystal NMC (SC-NMC) has emerged as a promising morphology for suppressing the mechanical instability by preventing intergranular cracking; however, robust methods of understanding its chemical degradation pathways are required. We demonstrate how a high-throughput data collection strategy unlocks the ability to perform 2D and 3D ptychography in minutes, where it currently requires hours, and combine this with X-ray absorption near edge spectroscopy (XANES) to visualise the local Ni oxidation state behaviour in SC-NMC811, with nanometre-scale spatial resolution, and use this as a proxy for state-of-charge. By employing this technique at various stages during lifetime cycling to high voltages (>4.2 V), direct mapping of chemical degradation along the Li channels, identification of nucleation sites, and observation of Ni oxidation state heterogeneities across both electrode and particle scales can be achieved. We further correlate these heterogeneities with the formation and growth of the rocksalt phase and oxygen-induced planar gliding. This methodology will advance the fundamental understanding of how high-Ni layered oxide materials chemically degrade during high-voltage operation, guiding the design of more durable battery materials.

cond-mat.mtrl-sci↗

arXiv2025

Compact laser-driven plasma X-ray source for time-resolved diffraction, spectroscopy, and imaging experiments at ELI Beamlines

Experimentally measured characteristics of a kHz laser-driven Cu plasma X-ray source that was recently commissioned at ELI Beamlines facility are reported. The source can be driven either by an in-house developed high contrast sub-20 fs near-infrared TW laser based on optical parametric chirped-pulse amplification technology, or by a more conventional Ti:sapphire laser delivering 12 mJ, 45 fs pulses. The X-ray source parameters obtained with the two driving lasers are compared. Measured photon flux of the order up to 10^{12} Kα photons/4π/s is reported. Furthermore, experimental platforms for ultrafast X-ray diffraction and X-ray absorption and/or emission spectroscopy based on the reported source are described.

physics.optics↗

arXiv2024

Plug-and-Play Half-Quadratic Splitting for Ptychography

Ptychography is a coherent diffraction imaging method that uses phase retrieval techniques to reconstruct complex-valued images. It achieves this by sequentially illuminating overlapping regions of a sample with a coherent beam and recording the diffraction pattern. Although this addresses traditional imaging system challenges, it is computationally intensive and highly sensitive to noise, especially with reduced illumination overlap. Data-driven regularisation techniques have been applied in phase retrieval to improve reconstruction quality. In particular, plug-and-play (PnP) offers flexibility by integrating data-driven denoisers as implicit priors. In this work, we propose a half-quadratic splitting framework for using PnP and other data-driven priors for ptychography. We evaluate our method both on natural images and real test objects to validate its effectiveness for ptychographic image reconstruction.

eess.IV↗

arXiv2023

High angular sensitivity X-ray phase-contrast microtomography of soft-tissue through a two-directional beam-tracking synchrotron set-up

Two-directional beam-tracking (2DBT) is a method for phase-contrast imaging and tomography that uses an intensity modulator to structure the X-ray beam into an array of independent circular beamlets that are resolved by a high-resolution detector. It features isotropic spatial resolution, provides two-dimensional phase sensitivity, and enables the three-dimensional reconstructions of the refractive index decrement, $δ$, and the attenuation coefficient, $μ$. In this work, we report on the angular sensitivity and the spatial resolution of 2DBT images in a synchrotron-based implementation. In its best configuration, we obtained angular sensitivities of $\sim$20 $n$rad and spatial resolution of at least 6.25 $μ$m in phase-contrast images. We also demonstrate exemplar application to the three-dimensional imaging of soft tissue samples, including a mouse liver and a decellularised porcine dermis.

physics.ins-det↗

arXiv2023

Direct x-ray scattering signal measurements in edge-illumination/beam-tracking imaging and their interplay with the variance of the refraction signals

X-ray dark-field or ultra-small angle scatter imaging has become increasingly important since the introduction of phase-based x-ray imaging and is having transformative impact in fields such as in vivo lung imaging and explosives detection. Here we show that dark-field images acquired with the edge-illumination method (either in its traditional double mask or simplified single mask implementation) provide a direct measurement of the scattering function, which is unaffected by system-specific parameters such as the autocorrelation length. We show that this is a consequence both of the specific measurement setup and of the mathematical approach followed to retrieve the dark-field images. We show agreement with theoretical models for datasets acquired both with synchrotron and laboratory x-ray sources. We also introduce a new contrast mechanism, the variance of refraction, which is extracted from the same dataset and provides a direct link with the size of the scattering centres. We show that this can also be described by the same theoretical models. We study the behaviour of both signals vs. key parameters such as x-ray energy and scatterer radius. We find this allows quantitative, direct, multi-scale scattering measurements during imaging, with implications in all fields where dark-field imaging is used.

physics.optics↗

arXiv2022

X-ray phase-contrast micro tomography of soft tissues using a compact laboratory system with two-directional sensitivity

X-ray micro tomography is a non-destructive, three-dimensional inspection technique applied across a vast range of fields and disciplines, ranging from research to industrial, encompassing engineering, biology and medical research. Phase-contrast imaging extends the domain of application of X-ray micro tomography to classes of samples that exhibit weak attenuation, thus appear with poor contrast in standard X-ray imaging. Notable examples are low-atomic-number materials, like carbon-fibre composites, soft matter and biological soft tissues. We report on a compact and cost effective system for X-ray phase-contrast micro tomography. The system features high sensitivity to phase gradients and high resolution, requires a low-power sealed X-ray tube, a single optical element, and fits in a small footprint. It is compatible with standard X-ray detector technologies: single-photon-counting offers higher sensitivity whereas flat-panels are preferred for a larger field of view. The system is benchmarked against known-material phantoms and its potential for soft-tissue three-dimensional imaging is demonstrated on small-animal organs: a piglet oesophagus and a rat heart.

physics.ins-det↗

arXiv2022

Fabrication of High-Aspect Ratio Nanogratings for Phase-based X-ray Imaging

Diffractive optical elements such as periodic gratings are fundamental devices in X-ray imaging - a technique that medical, material science and security scans rely upon. Fabrication of such structures with high aspect ratios at the nanoscale creates opportunities to further advance such applications, especially in terms of relaxing X-ray source coherence requirements. This is because typical grating-based X-ray phase imaging techniques (e.g., Talbot self-imaging) require a coherence length of at least one grating period and ideally longer. In this paper, the fabrication challenges in achieving high aspect-ratio nanogratings filled with gold are addressed by a combination of laser interference and nanoimprint lithography, physical vapor deposition, metal assisted chemical etching (MACE), and electroplating. This relatively simple and cost-efficient approach is unlocked by an innovative post-MACE drying step with hexamethyldisilazane, which effectively minimizes the stiction of the nanostructures. The theoretical limits of the approach are discussed and, experimentally, X-ray nanogratings with aspect ratios >40 demonstrated. Finally, their excellent diffractive abilities are shown when exposed to a hard (12.2 keV) monochromatic x-ray beam at a synchrotron facility, and thus potential applicability in phase-based X-ray imaging.

physics.app-ph↗

arXiv2021

X-ray Ptychography with a Laboratory Source

X-ray ptychography has revolutionised nanoscale phase contrast imaging at large-scale synchrotron sources in recent years. We present here the first successful demonstration of the technique in a small-scale laboratory setting. We conducted an experiment with a liquid metal-jet X-ray source and a single photon-counting detector with a high spectral resolution. The experiment used a spot size of 5 microns to produce a ptychographic phase image of a Siemens star test pattern with a sub-micron spatial resolution. The result and methodology presented show how high-resolution phase contrast imaging can now be performed at small-scale laboratory sources worldwide.

physics.app-ph↗