Conventional X-ray computed tomography (XCT) is well-established for 3D imaging of static, slowly moving, or quasi-statically loaded objects. However, many structural instabilities and dynamic phenomena remain undetectable under such conditions. This study addresses the need for tomographic analysis of periodically oscillating objects, which is beyond the capabilities of conventional XCT and may yield inaccurate results when relying solely on techniques such as laser Doppler vibrometry. We present a novel phase-locked XCT methodology designed to capture the internal structure and deformation modes of periodically vibrating objects. The approach enables phase-synchronized acquisition of projection data, providing high-resolution volumetric insight into both the geometry and dynamic behavior of oscillating structures. To realize this technique, we developed a custom XCT system that incorporates real-time hardware synchronization and dedicated control and image acquisition software. The system’s performance is demonstrated through the modal analysis of an oscillating cantilever beam, with dynamic volumes compared to reference scans of the static state. The results validate the system’s capability to serve as a fundamental modality for dynamic structural analysis, offering enhanced reliability in identifying internal deformation patterns during oscillatory motion.

Conventional X-ray Computed Tomography is a robust modality for the volumetric characterization of static or quasi-statically loaded specimens. However, standard acquisition protocols are inherently limited when resolving high-frequency dynamic phenomena or structural instabilities in oscillating systems due to motion blur and temporal undersampling. To overcome these constraints, this study introduces a novel phase-locked XCT methodology designed for the four-dimensional analysis of periodically vibrating structures. The proposed approach utilizes a hardware-level phase-synchronization protocol to correlate X-ray projections with specific temporal states of the oscillation cycle. This enables the reconstruction of high-resolution volumetric datasets that characterize both the internal geometry and complex deformation modes of the specimen. The methodology was implemented using a custom-engineered XCT platform featuring real-time hardware synchronization and dedicated control architecture. The system’s efficacy is demonstrated through the modal analysis of an oscillating cantilever beam. By comparing reconstructed dynamic volumes against static reference states, we validate the system’s performance as a high-fidelity modality for dynamic structural characterization. The results confirm that this technique provides a reliable ground truth for identifying internal deformation patterns and evaluating structural integrity during continuous oscillatory motion.

Paper architectural models represent a distinct category of cultural heritage objects, characterized by a combination of lightweight organic materials with denser structural and decorative elements. Their fragility and material heterogenity pose challenges for non-destructive examination, such as X-ray computed tomography. To the authors' knowledge, the systematic application of X-ray computed tomography to historical paper architectural models has not yet been published, despite its potential to reveal internal structures and undocumented interventions. In this study, three paper architectural models by Antonín Langweil, which represent unique documentation of the appearance of Prague in the first half of the 19th century, were examined using X-ray computed tomography. The method was proven suitable for mapping hidden damage related to ageing, mechanical stress, and biological degradation. Furthermore, supplementary X-ray fluorescence and UV fluorescence were used to analyse the material composition. Besides documentation capabilities, the combination of computed X-ray tomography and X-ray fluorescence analysis made it possible to identify specific areas with material differences that may indicate secondary interventions. The methodology presented here offers new insights into Langweil's technological processes, supports informed decision making in preventive conservation, and highlights the broader potential of advanced imaging methods for the study and documentation of fragile heritage objects composed of multiple materials.

X-ray computed tomography with laboratory imaging chains often struggles with high-speed processes, as recording a single tomographic dataset quickly enough is often a challenging task. This paper presents a method for extracting the eigenmode of a harmonically excited oscillating object based on a probabilistic analysis of its tomographic reconstruction. In the standard reconstruction of an oscillating object, where the recording of tomography data is realised over a relatively long period of time, the highest probability of the object occurrence is in its amplitudes. Based on this fact, it is possible to identify the eigenshape of the oscillating object by searching for the envelope of its motion. The identified modal shapes show good agreement with the laser Doppler vibrometer measurements. Consequently, the effectiveness of the method was demonstrated for objects that are unsuitable for traditional laser vibrometry due to their shape or surface limitations.

In this work, an in-situ study of phase transitions in low-carbon steel is presented. The phase changes were monitored by the transmission energy dispersive X-ray diffraction technique during the heating, annealing and quenching cycle of the sample under standard laboratory conditions. During energy dispersive X-ray diffraction, the sample volume was transmitted with a pencil beam generated by a standard polychromatic X-ray tube without any spectral filtering. Two-dimensional polychromatic diffraction images were acquired by a Timepix 3 pixelated detector. This detector is capable of achieving a throughput of up to 38 Mhits/s in continuous stream mode using USB 3.0 interface. For each detected photon, its position is known with an accuracy of 55 µm in the detector plane and its energy with a resolution of 4 keV at 60 keV. The recorded polychromatic data is then recomputed to get the equivalent monochromatic XRD pattern that would be produced using a monochromatic X-ray source. Thanks to the 90 kV voltage potential of the X-ray tube, the polychromatic pencil beam was able to pass through a highly attenuating sample made of 1.5 thick steel sheet. In addition, by utilizing the entire X-ray spectrum, the pencil beam has a sufficiently high brilliance to obtain XRD patterns rapidly enough to investigate relatively fast processes with temporal resolution of 10 s. It made to possible to analyze the phase transitions in a polycrystalline sample during its temperature treatment under standard laboratory conditions.

X-ray computed tomography is a standard method of non-destructive testing of a wide range of static objects. In recent years, time -dependent tomography has been on the rise, for which it is necessary to acquire a series of tomographic data covering the event of interest. For slower processes, conventional laboratory X-ray computed tomography (CT) scanners can be used, while when events are faster, a very intense X-ray source is usually required. For high resolution requirements, the need for an intense X-ray source leads to the use of a synchrotron. An exception is tomographic tracking of periodic events. As will be shown, for these, a good quality reconstruction can be achieved even in the case of a relatively low -intensity X-ray source. To avoid blurring of the individual X-ray images by the motion of the object, the exposure time must be reasonably short. At motion rates of units of Hz, this time cannot be longer than tens of ms, this requirement naturally leads to low data statistics. Sufficient statistics is achieved by integrating images taken at an identical position of the moving object. A key requirement of such an approach is the precise synchronization of all active components of the system. The imaging detector must be capable of taking images on demand by hardware triggering with the capability of adequately short exposures. The ability of the CT system to investigate periodically moving objects will be demonstrated on the object oscillating harmonically at 3.81 Hz.

In the field of experimental mechanics, X-ray computed tomography is a well-established method for non-destructive testing of a wide range of objects. It is quite common to employ digital volumetric correlation to evaluate the deformation of bodies by comparing their initial and current state. Time-dependent tomography, which works with tomographic data sets covering the entire process under investigation, has also been on the rise in recent years. However, we must keep in mind that a single tomographic data set represents thousands of X-ray images, making such measurements quite demanding in terms of instrumentation and subsequent data processing. For events taking minutes or longer, conventional laboratory X-ray computed tomography scanner can be used, while for faster events a very intense X-ray source is usually required, which typically leads to the use of a synchrotron. From a particular speed, even synchrotron sources may no more be enough. An exception is tomographic tracking of purely periodic events, such as the oscillation of a beam at its natural frequency. As will be shown, despite the relatively high velocity of motion, a good reconstruction can be achieved even with a conventional X-ray source. Thus, we obtain information not only about the intrinsic shape of a particular beam, but also about its internal structure. It will be possible, for example, to investigate how any local imperfections may affect the shape of the vibration, assuming that some defects may not be apparent under static loading. Specifically, this paper will show the results of a tomographic reconstruction of a slender beam oscillating at 4.15 Hz.

This paper presents the use of X-ray computed tomography and X-ray fluorescence in the analysis and expert research of the seventeenth century printed book "Eukhologīon albo Molitoslov, ili Trebnik" from Kiev. The main purpose of the survey was to confirm whether the book binding is original or whether it is a rebinding, and whether there are any fragments of the hidden older texts. Commonly used radiography is usually not able to provide sufficient information for these purposes. On the other hand, computed tomography allows a detailed and three-dimensional documentation of the bookbinding technology and the structure of the materials used, including the wooden boards. It will be presented that all elements of the weave are clearly visible, making it possible to show that there are no internal defects in the stitching and materials. It has also been convincingly shown that there are no fragments or layers of older texts in the binding, so no further invasive intervention will be necessary regarding this aspect. The paper also demonstrates the possibility of reading the text in a closed book utilising X-ray computed tomography data; this option may be advantageous for massively damaged manuscripts. It will also be shown, that thanks to detailed tomographic imaging of the wood structure of the boards, a dendrochronological survey can be successfully carried out without invasive intervention into their outer layers. From the CT data it was also found that the pigments of the letters have significantly different densities. Therefore, as part of the survey, elemental analysis of the writing was also carried out using a portable X-ray fluorescence spectrometer to confirm and clarify this finding.

Abstract This work presents the use of X-ray computed tomography and X-ray fluorescence in analyses and expert surveys of historical manuscripts and early prints. Historic early prints and manuscripts retain much information about their origins, owners and creators, or various defects hidden in the book binding or hidden between layers of material. The Department of Research Laboratories of the National Library of the Czech Republic has long been involved in non-invasive methods of making visible and documenting information that is not available during normal historical or restoration research. The book that was selected for the survey was a 17th-century historical print of the collection of the Slavic Library originally from Kiev, with the full title Eukhologīon albo Molitoslov, ili Trebnik. The main purpose of the survey was to confirm whether the book binding is original or whether it is a rebinding, and whether there are no fragments of older texts in the binding. Radiography was unable to provide sufficient quality documents confirming or refuting the binding or the presence of layers in the book binding carrying the text. Computed tomography made it possible to display detailed structure of bookbinding materials, including wooden boards. No fragments or layers with older texts were found in the structure of the book binding therefore, there is no need for invasive intervention. All binding elements were visible and no internal defects in materials and stitching were detected. The possibility of reading text in a closed book based on X-ray computed tomography will be presented, as this option may be advantageous for massively damaged manuscripts. Thanks to a very detailed representation of the wood structure using tomography, it was possible to carry out a dendrochronological survey without invasive intervention. Dendrochronological analysis confirmed the original bookbinding materials corresponding to the age of early printing. As part of the survey, an elemental analysis of the font was also carried out using an X-ray fluorescence spectrometer. The letters in the CT reconstruction have significantly different contrasts. The different elemental composition of the printing inks was verified using XRF analysis.

Abstract This work presents the use of X-ray computed tomography and X-ray fluorescence in analyses and expert surveys of historical manuscripts and early prints. Historic early prints and manuscripts retain much information about their origins, owners and creators, or various defects hidden in the book binding or hidden between layers of material. The Department of Research Laboratories of the National Library of the Czech Republic has long been involved in non-invasive methods of making visible and documenting information that is not available during normal historical or restoration research. The book that was selected for the survey was a 17th-century historical print of the collection of the Slavic Library originally from Kiev, with the full title Eukhologīon albo Molitoslov, ili Trebnik. The main purpose of the survey was to confirm whether the book binding is original or whether it is a rebinding, and whether there are no fragments of older texts in the binding. Radiography was unable to provide sufficient quality documents confirming or refuting the binding or the presence of layers in the book binding carrying the text. Computed tomography made it possible to display detailed structure of bookbinding materials, including wooden boards. No fragments or layers with older texts were found in the structure of the book binding therefore, there is no need for invasive intervention. All binding elements were visible and no internal defects in materials and stitching were detected. The possibility of reading text in a closed book based on X-ray computed tomography will be presented, as this option may be advantageous for massively damaged manuscripts. Thanks to a very detailed representation of the wood structure using tomography, it was possible to carry out a dendrochronological survey without invasive intervention. Dendrochronological analysis confirmed the original bookbinding materials corresponding to the age of early printing. As part of the survey, an elemental analysis of the font was also carried out using an X-ray fluorescence spectrometer. The letters in the CT reconstruction have significantly different contrasts. The different elemental composition of the printing inks was verified using XRF analysis.

In the contribution, we present a laboratory system capable of X-ray computed tomography (XCT) scanning of an periodically moving or oscillating object. The system is an in-house developed XCT setup with electromagnetic voice coil actuator mounted on top of the rotary stage of the setup. The strict synchronization of the components, the rotary stage, the electromagnetic actuator movement and the detector readout is accomplished with use of the detector hardware trigger and hard real-time Linux operating system. Cylindrical sample manufactured from epoxy resin with metal particles to enable movement tracking is scanned in a stationary position and during periodical movement induced by the vibration stage. The volumetric data of the scans is compared and the results of this contribution represent an important step towards identification of defects through modal analysis of in-situ harmonically vibrating object.

The use of computed tomography (CT) for studying artwork has a long tradition in the restoration and care of collections in memory institutions. The result of the related tomographic reconstruction is a virtual spatial model in which we can examine the production technology, the internal structure, various damaged areas, and previous restoration interventions. The extension of standard CT to dual energy CT provides additional information to help distinguish materials with similar densities but different chemical compositions. As will be shown, pigment differences that appear very similar in optical light can be identified in this way. The differences found were confirmed by X-ray fluorescence and Raman spectroscopy analytical techniques. Current laboratory CT scanners make it possible to examine the layered structures of paintings and polychrome sculptures. In the case of wood panel paintings, however, we are faced with the common deformation of the panels. So, when examining the CT data, we can only see a small section of the paint layer, and it is difficult to examine the whole artwork in its entire context. This disadvantage can be solved by a virtual straightening of the panel, as will be demonstrated.

This paper presents an investigation of wooden artworks from the collection of the National Gallery Prague created by Monogrammist IP–one of the top carvers of the Salzburg-Passau region at the beginning of the 16th century. His wood reliefs were examined to gain a better understanding of the historical techniques used in medieval art workshops. The internal structure of the small relief Visitation was analysed using computed tomography. Tomographic reconstruction made it possible to distinguish wood species, observe the internal structure of the artwork in detail, study the technological procedures and identify earlier repairs, additions and damages. Tomographic investigation proved the use of four types of wood on the relief Visitation, most likely pear, lime, unspecified softwood and other different species used for joining dowels. A combination of non-invasive and micro-destructive analytical techniques was employed for the chemical characterisation of the materials in the surface layers of the artworks. Photomicrographs of the surface were taken to provide material for the initial investigation. Non-invasive material research was conducted using a portable X-ray fluorescence analyser and, in selected cases, an external reflection infrared spectrometer. The detailed analyses on the micro-samples was carried out by optical microscopy, micro-Raman spectroscopy, Fourier transform infrared spectroscopy, scanning electron microscopy coupled with energy dispersive X-ray spectrometry and gas chromatography with mass spectrometry. A glaze layer based on protein with earth pigment was identified on the relief Christ the Saviour from Death.

V minulých desetiletích se výpočetní rentgenová tomografie užívala v restaurátorské a sbírkové praxi většinově na průzkum sochařských děl spíše než pro průzkum maleb. Návazně na technické inovace se však stále více ukazuje, že tato metoda může významně přispět i k poznání vnitřní struktury maleb a jejich podložky. V případě maleb na dřevěné podložce získáváme pomocí výpočetní tomografie také přesná data o dřevní hmotě, konstrukci a technologických detailech podložky. Míra detailu u laboratorních CT umožňuje výsledky tomo- grafických měření využít při dendrochronologickém datování. Zároveň nám při vhodném zpracování naměřená data poskytují mimořádně přesný záznam o stavu díla. Lze například dokumentovat soudržnost spojů, deformity, praskliny či druhotné zásahy v hmotě dřeva, stejně tak jako některé technologické detaily přípravy podložky a samotné malby a užitých výzdobných technik. Další zajímavou aplikací RTG výpočetní tomografie je identifikace druhu dřeviny u vzorků, které jsou díky svým malým rozměrům a tvaru nevhodné pro standardní metodu optické mikroskopie. V takovém případě nám výpočetní tomografie s mikrometrickým rozlišením může poskytnout pohled na 3D struk- turu vzorku dřeva a lze tak rozpoznat některé charakteristické znaky jednotlivých dřevin. Některé ze zmíněných informací je přitom jinými metodami obtížné, někdy i nemožné získat. Potenciální přínos výpo- četní tomografie pro průzkum uměleckých děl výrazně zvyšuje také práce s daty upravenými pomocí speciálních softwarových nástrojů.

In December 2019, an expedition on Mt. Ebal to examine the discarded material from Adam Zertal’s 1982–1989 excavation yielded a small, folded lead tablet. The east dump pile, from which the object emerged, contained the discarded matrix from two structures that he interpreted as altars dated to the Late Bronze Age II and Iron Age I. The earlier and smaller round altar lay underneath the geometric center of the later and larger rectangular altar. The tablet could not be opened without damaging it. A team of scientists performed X-ray tomographic measurements with different scanning parameters. The tomographically reconstructed data were subjected to advanced processing to reveal the hidden text. Epigraphic analysis of the tomographic data revealed a formulaic curse written in a proto-alphabetic script likely dating to Late Bronze Age II. The inscription falls within the literary genre of Chiastic Parallelism and predates any previously known Hebrew inscription in Israel by at least 200 years.

High-resolution X-ray computed micro-tomography (CT) is a powerful technique for studying the processes of crack propagation in non-homogenous quasi-brittle materials such as rocks. To obtain all the significant information about the deformation behaviour and fracture characteristics of the studied rocks, the use of a highly specialised loading device suitable for the integration into existing tomographic setups is crucial. Since no adequate commercial solution is currently available, a completely newly-designed loading device with a four-point bending setup and vertically-oriented scanned samples was used. This design of the loading procedure, coupled with the high stiffness of the loading frame, allows the loading process to be interrupted at any time and for CT scanning to be performed without the risk of the sudden destruction of the scanned sample. This article deals with the use of the 4D CT for the visualisation of crack initiation and propagation in clastic sedimentary rocks. Two types of quartz-rich sandstones of Czech provenance were used for tomographic observations during the four-point bending loading performed on chevron notched test specimens. It was found that the crack begins to propagate from the moment that ca. 80 % of the maximum loading force is applied.

It is well known that the measured values of the fracture toughness of quasi brittle materials are influenced by material heterogeneity, dimensions, boundary conditions, and unequal tension and compression properties.Standard testing methods supposing isotropic material, in contrary the quasi-brittle materials differ from this theoretical expectation, therefore this approach may fail.The authors present Local Fracture Toughness Testing (LFTT) method to overcome this obstacle.LFFT based on a complex methodology using a series of tomographic reconstructions recorded during specimen loading is calculated independently of the outside boundary conditions.

This work focuses on the non-destructive identification of delamination in layered structures utilizing the X-ray phase contrast effect. This effect naturally occurs on sharp edges, material interfaces and fine textures, and can be retrieved from radiographic data even without any grating in special cases, as will be demonstrated for the layered carbon fibre reinforced plastic composites used in the aerospace industry. Such delamination can be described as the local disbonding of composite layers, which often occurs due to the cyclic loading of the structural elements while in service. Such a flaw may significantly decrease its bearing capacity, and therefore periodic non-destructive inspection is needed. Aside from ultrasound inspection, which provides limited resolution and detectability, X-ray imaging and tomography is widely used in practise. Nevertheless, the identification of delamination may be difficult utilizing X-ray computed tomography, as delaminated faces may remain in contact — the defect has negligible volume. On the other hand, the distance between faces is not relevant for X-ray phase contrast imaging. In addition, access to the structural elements is often limited for X-ray imaging. For shaped parts, it will be shown in this work that limited access is not as critical a problem in comparison with standard computed tomography.

In this paper, defect inspection related to an epoxy underfilling process between integrated circuits (ICs) and printed circuit boards (PCBs) is presented utilizing the data fusion of multipositional computed tomography (DFMCT). The work aims to verify the existence of underfilling epoxy which was not possible utilizing standard computed tomography due to strong metal artifacts created by ball grid array (BGA) packages. By interpreting the results obtained from the scanned samples, we were able to correlate the excess epoxy defects and the success of the underfilling process. We present the data fusion approach as an alternative method when traditional metal artifact reduction methods would be insufficient. The study was commenced by making a proper radiographic simulation using aRTist simulation software. The simulation enabled us to choose the right mounting positions which produce less metal artifacts for the experimental study. The DFMCT was achieved by acquiring multiple computed tomographic scans at different sample orientations. The reconstructed volumes were then aligned, and the fused volume was obtained by combining the corrected data and suppressing the disrupted data of the reconstructed volumes.