Synchrotron Radiation Imaging Technique Research Articles

Roentgenoscopy of laser-induced projectile impact testing.

Laser-induced projectile impact testing (LIPIT) based on synchrotron imaging is proposed and validated. This emerging high-velocity, high-strain microscale dynamic loading technique offers a unique perspective on the strain and energy dissipation behavior of materials subjected to high-speed microscale single-particle impacts. When combined with synchrotron radiation imaging techniques, LIPIT allows for in situ observation of particle infiltration. Two validation experiments were carried out, demonstrating the potential of LIPIT in the roentgenoscopy of the dynamic properties of various materials. With a spatial resolution of 10 µm and a temporal resolution of 33.4 µs, the system was successfully realized at the Beijing Synchrotron Radiation Facility 3W1 beamline. This innovative approach opens up new avenues for studying the dynamic properties of materials in situ.

Using Synchrotron Radiation Imaging Techniques to Elucidate the Actions of Hexarelin in the Heart of Small Animal Models.

The majority of the conventional techniques that are utilized for investigating the pathogenesis of cardiovascular disease in preclinical animal models do not permit microlevel assessment of in situ cardiomyocyte and microvascular functions. Therefore, it has been difficult to establish whether cardiac dysfunction in complex multiorgan disease states, such as heart failure with preserved ejection fraction and pulmonary hypertension, have their origins in microvascular dysfunction or rather in the cardiomyocyte. Herein, we describe our approach of utilizing synchrotron radiation microangiography to, first, ascertain whether the growth hormone secretagogue (GHS) hexarelin is a vasodilator in the coronary circulation of normal and anesthetized Sprague-Dawley rats, and next investigate if hexarelin is able to prevent the pathogenesis of right ventricle (RV) dysfunction in pulmonary hypertension in the sugen chronic hypoxia model rat. We show that acute hexarelin administration evokes coronary microvascular dilation through GHS-receptor 1a and nitric oxide, and through endothelium-derived hyperpolarization. Previous work indicated that chronic exogenous administration of ghrelin largely prevented the pathogenesis of pulmonary hypertension in chronic hypoxia and in monocrotaline models. Unexpectedly, chronic hexarelin administration prior to sugen chronic hypoxia did not prevent RV hypertrophy or RV cardiomyocyte relaxation impairment. Small-angle X-ray scattering revealed that super relaxed myosin filaments contributed to diastolic dysfunction, and that length-dependent activation might contribute to sustained contractility of the RV. Thus, synchrotron-based imaging approaches can reveal novel insights into cardiac and coronary functions in vivo.

Time invariance of three-dimensional morphology of equiaxed dendrite: A phase-field study

Dendrite morphology has a significant effect on solute segregation and fluid flow in bulk metallic materials. Therefore, the detailed morphological evolution of dendrites is important to better understand these processes. Recently, three-dimensional (3D) dendrite morphology has been analyzed using interface shape distribution (ISD) maps that are spanned by the curvedness and shape factor of the local solid−liquid interface in an Al−Cu alloy. Data were collected through in-situ observations using synchrotron radiation imaging techniques [J.W. Gibbs et al.: Sci. Rep., 5 (2015) 11824]. This methodology is quite effective for describing 3D dendrites. In this study, we thoroughly investigated the morphological evolution and the related ISD map of free-growing equiaxed dendrites in an Al−3mass%Cu alloy using a quantitative phase-field model. The ISD was found to differ depending on the degree of undercooling. Importantly, the results indicate the presence of a time-invariant feature after sufficient branching and growth of secondary arms, when the degree of undercooling is substantial enough to produce a bunch of branching. The time invariance is considered a universal feature of equiaxed dendrite growth.

Synchrotron Radiation-Based Refraction-Contrast Tomographic Images Using X-ray Dark-Field Imaging Optics in Human Lung Adenocarcinoma and Histologic Correlations.

The aim of this study was to evaluate the clinical implication of synchrotron radiation imaging techniques for human lung adenocarcinoma in comparison with pathologic examination. A refraction-based tomographic imaging technique called the X-ray dark-field imaging (XDFI) method was used to obtain computed tomographic images of human lung adenocarcinoma at the beam line at Photon Factory BL 14B at the High Energy Accelerator Research Organization (KEK) in Tsukuba, Japan. Images of normal lung tissue were also obtained using the same methods and reconstructed as 3D images. Both reconstructed images were compared with pathologic examinations from histologic slides which were made with identical samples. Pulmonary alveolar structure including terminal bronchioles, alveolar sacs, and vasculatures could be identified in synchrotron radiation images of normal lung. Hyperplasia of interstitial tissue and dysplasia of alveolar structures were noticed in images of lung adenocarcinoma. Both synchrotron radiation images were considerably correlated with images from histologic slides. Lepidic patterns of cancer tissue were distinguished from the invasive area in synchrotron radiation images of lung adenocarcinoma. Refraction-contrast tomographic techniques using synchrotron radiation could provide high-resolution images of lung adenocarcinoma which are compatible with those from pathologic examinations.

Effect of the degree of supercooling on growth mechanism of Cu6Sn5 in pure Sn/Cu solder joint

The growth mechanism of Cu6Sn5 intermetallic compound (IMC) at Sn/Cu interface reflowed under 250 °C, 275 °C, and 300 °C for a duration of 60 s and undergoing highly pressurized air action (HP), water cooling (WC), air cooling (AC) or furnace cooling (FC) in the aftermath has been outlined. In addition, synchrotron radiation imaging technique has been utilized to in situ observe interfacial Cu6Sn5 grains growth. It has been revealed that the morphologies of Cu6Sn5 grains under HP and AC are both scallop-like, whereas the samples processed with HP and FC bear plane structure and prismatic morphologies. These revelations indicate the secondary growth of Cu6Sn5 grains during the cooling stage as the significant determinant of the final IMC morphology. Thus, continuous growth on the rough surface (M1), spiral dislocation growth (M2), and 2D nucleation and growth (M3), have been proposed to explain the observed morphologies of interfacial Cu6Sn5 grains. M1 has been recognized as the principal mechanism responsible for IMC morphology undergoing water cooling, whereas combination of M1 and M2 decide the morphological feature of interface resulting from air cooling. Finally, all of the three mechanisms (M1, M2 and M3) account for the IMC morphology corresponding to furnace cooling. As all of these three growth mechanisms are affected by the degree of supercooling (ΔT), it is inferred that the ΔT can influence the secondary nucleation of IMC at the cooling stage. With the fact that the homogeneous nucleation occurs at larger ΔT, and the relative favorability for heterogeneous nucleation at smaller ΔT; the growth mechanisms can be mapped with the degree of undercooling. Consequently, the IMC growth mechanisms proposed and their association with ΔT, can be used to obtain an appropriate thickness and morphology of IMC to improve the reliability of solder joints.

In situ infiltration behavior and interfacial microstructure evolution between Al and carbon fibers

The infiltration process of Al into unidirectional carbon fiber (CF) bundles was observed using in situ synchrotron radiation imaging technique. The effects of surface metallization and matrix alloying on the infiltration behavior were studied. The infiltration process of the original Al/CF couple was a physical filling process due to the poor wettability. Thus, the observed infiltration distance presented an approximately linear increase over time. With Ni coatings, the improvement in the wetting behavior changed the infiltration process to spontaneous infiltration, and the average infiltration velocity significantly increased from 0.25 μm/s to 0.72 μm/s. The spontaneous infiltration behavior was further improved by stronger Al-Mg-Ni reaction during matrix alloying, and the velocity increased to 0.91 μm/s. For the CF reinforced Al-matrix composites fabricated by a rolling method, an improved infiltrated microstructure with few defects was obtained under surface metallization and matrix alloying due to the multi-element interfacial reaction.

Microstructure and growth kinetic study in Sn–Cu transient liquid phase sintering solder paste

The feasibility of the highly reliable and replicable microstructure formation of the transient liquid phase sintering (TLPS) paste during the early soldering and isothermal aging on the Cu substrate had been successfully investigated in this study. By using the Sn–0.7 wt% Cu (SC) solder paste as the base material and the Cu particles in the production of the TLPS Sn–10 wt% Cu (SC10) solder paste, the ensuing Cu6Sn5 phase from the isothermal aging process was found to have reduced the β-Sn area of the bulk SC10 solder microstructure. The growth kinetic for TLPS SC10 resulted in a 26.76 kJ/mol of activation energy level. The real-time synchrotron radiation imaging technique that was employed in studying the growth and formation of the primary intermetallic phases at the solder joints had also discovered the primary intermetallic in TLPS SC10 was not only found to have experienced an early nucleation just after the solder had melted, but its growth was also restricted prior to the solidification of the liquid solder. Therefore, the relevance of the results that were obtained from this research may offer a possible solution for aiding the future development of highly reliable solder joints in high temperature solder applications.

First attempt to visualize otolith motion in-situ using synchrotron radiation imaging techniques

Regarding the basics of ear structure-function relationships in fishes, there is still a substantial lack of knowledge of functional morphology. In particular, the actual motion of the solid otolith relative to the underlying sensory epithelium in the ear has rarely been investigated. To date, analyses of otolith motion have been mainly based on mathematical modeling which have yielded conflicting results. Outcomes of a recent modeling study suggest that otolith motion is not a simple oscillation, but depends on the 3D shape of the otolith, among other factors. Our study thus aims to provide experimental data to test previous models of otolith motion focusing on the relationship between different species-specific otolith shapes and their respective influence on otolith motion. As in-situ investigation of the basic parameters of otolith motion requires an approach with high spatial and temporal resolution, we used synchrotron radiation imaging techniques. In our comparative approach including the anatomically well studied and closely related cichlid species Steatocranus tinanti (vestigial swimbladder) and Etroplus maculatus (swimbladder-inner ear connection), we studied the relative motion of the saccular otolith and surrounding tissues provoked by sound stimuli at 0.2 and 0.5 kHz. We will discuss first results as well as methodological aspects.

Microstructure and strength of AlN–SiC interface studied by synchrotron X-rays

Bulk AlN crystals grown by sublimation on SiC substrates exhibit relatively high dislocation densities. The kind of defect formation at early growth stages influences the structural quality of the grown crystals. In this work, the dislocation distribution near to the interface is understood through investigation of thin (≤1.5 mm) continuous (non-cracked) freestanding crystals obtained in one process with the evaporation of the substrates. The AlN specimens were characterized using synchrotron radiation imaging techniques. We revealed by triple-axis X-ray diffraction study that, near to the former interface, randomly distributed dislocations configured to form boundaries between \(\sim \)0.02\(^{\circ }\) misoriented sub-grains (from [0001] direction). Threading dislocation structure similar to that in epitaxial GaN films was not detected. To explain these observations, a theoretical model of misfit stress relaxation near the interface is suggested.

On the increase of intermetallic compound's thickness at the cold side in liquid Sn and SnAg solders under thermal gradient

The thermal gradient induced intermetallic compound growth at the cold side of the Cu/Sn/Cu and Cu/Sn–3.5Ag/Cu solders heated at 350° has been in situ studied using synchrotron radiation imaging technique. Finite element model for thermotransport of Cu from hot end to cold end in Cu/Sn/Cu solder is implemented for the description of the associated growth of the compound. Higher temperature and bigger solder volume are observed as favorable parameters for the rate of thickness increase in both Sn and SnAg solders. In case of SnAg system, the formation of Ag3Sn particle, causing retardation effects in the growth of Cu6Sn5 compound, subsequently induces a lowered resulting thickness.

Modeling the diffusion-driven growth of a pre-existing gas bubble in molten tin

Finite element method is utilized to solve the diffusion equation and model the diffusion driven growth of a pre-existing spherical gas bubble in molten tin at the solder/substrate interface for reflow time of 120 s and temperature of 250 °C. The gibbs free energy change required for determining the equilibrium concentration at liquid solder/gas bubble boundary was calculated using the thermodynamic polynomial coefficients. The rate of change of radius, as function of concentration flux, is calculated using the lagrangian mesh update methodology. With an initial diameter of 20 μm, the bubble growth is calculated as a function of contact angle. When the wetting angle is varied from a value of 30° to 135°, the numerical calculation has yielded the final sizes for the bubble to change from 62.87 μm to 82.8 μm respectively. The effect of wetting transition in the growth of bubble was studied by the in-situ observation of bubble dynamics through synchrotron radiation imaging technique. The scanning electron microscopy images of the morphologies of intermetallic compounds influenced by growing bubble in Sn/Cu solder joint and bubble pictures obtained through synchrotron radiation are utilized to get the experimental size of the bubble. The mean experimental bubble diameter has been obtained as 76.39 μm. The growing bubble inhibits the growth of intermetallic compound at its vicinity and thereby reduces the strength of solder joints.

Phase contrast tomography of the mouse cochlea at microfocus x-ray sources

We present phase contrast x-ray tomography of functional soft tissue within the bony cochlear capsule of mice, carried out at laboratory microfocus sources with well-matched source, detector, geometry, and reconstruction algorithms at spatial resolutions down to 2 μm. Contrast, data quality and resolution enable the visualization of thin membranes and nerve fibers as well as automated segmentation of surrounding bone. By complementing synchrotron radiation imaging techniques, a broad range of biomedical applications becomes possible as demonstrated for optogenetic cochlear implant research.

Real time observation of equiaxed growth of Sn–Pb alloy under an applied direct current by synchrotron microradiography

The equiaxed growth of Sn–50wt% Pb alloy with an applied direct current (DC) was investigated using an updated synchrotron radiation imaging technique, i.e. the diffraction enhanced imaging (DEI). Without DC, dendrites grew in an irregular manner due to the gravity-driven fluid flow; while imposing DC, the dendrites grew in an isotropous manner and more equiaxed morphology of grains was finally obtained. The electromagnetic flow induced by DC decreased the pileup of solute ahead of the growing solid/liquid interface and promoted the growth of the dendrites situated aside and below. Quantitative analysis on the growth rate of dendrites indicated that the interactions between dendrites were strengthened when imposing DC. It was thus believed that, with DC treatment, the formation of finer and more equiaxed grain structure is mainly attributed to the suppressed growth and strengthened interaction of growing grains.

Real time imaging on dendrite morphology evolution during alloy solidification under electric field

The dynamic dendrites growth of metallic alloy during the solidification can not be in-situ observed since the metallic alloy is in optically opaque. It is also not possible to in-situ study the influence of electric current on dendrites growth behaviour. By using synchrotron radiation imaging technique, the evolution of dendrite morphology under an electric current is observed. Results indicate that the direct current can significantly suppress the dendrites growth and the dendrite tip tends to be round from sharp. Increasing the current intensity, the dendrite tip splits due to the current crowding and solute pileup around the round tip. The pulsed electric current can significantly enhance the solidification rate and refine the primary and secondary dendrite arm spaces because of the thermal and mechanical shock around solid/liquid interface.

Elemental and magnetic sensitive imaging using x-ray excited luminescence microscopy

We demonstrate the potential of x-ray excited luminescence microscopy for full-field elemental and magnetic sensitive imaging using a commercially available optical microscope, mounted on preexisting synchrotron radiation (SR) beamline end stations. The principal components of the instrument will be described. Bench top measurements indicate that a resolution of 1 μm or better is possible; this value was degraded in practice due to vibrations and/or drift in the end station and associated manipulator. X-ray energy dependent measurements performed on model solar cell materials and lithographically patterned magnetic thin film structures reveal clear elemental and magnetic signatures. The merits of the apparatus will be discussed in terms of conventional SR imaging techniques.

Optic Nerve Imaging Using Synchrotron Radiation (P07.254)

Objective: We performed experimental synchrotron radiation (SR) imaging techniques on the leporine optic nerve to see if high resolution, detailed images of optic nerve microstructure could reliably be obtained. Our long term objective is to pursue safe in vivo imaging for the development of animal models for the study of optic neuropathies. Background There are no previous SR imaging studies of the optic nerve in either humans or animals. SR imaging techniques including diffraction enhanced imaging (DEI), and CT planar imaging have been successfully used to image biological tissues including the porcine eye, murine internal organs, canine articular cartilage, and human breast cancer tissue. Design/Methods: Specimen preparation included previously frozen dissected rabbit globes, optic nerves and chiasm, and one whole rabbit head. These samples were preserved and imaged in 10% formalin. A double crystal monochromator was used to select a very small energy band from the polychromatic synchrotron beam. The monochromatic beam passed through samples, with an analyzer crystal similar to that in the monochromator placed after the sample. Results: The analyzer crystal was sensitive to the refractive effects within the samples. In addition, absorption and scattering effects were used to create images with differing contrast properties. By moving the analyzer crystal various images of the optic nerve and ocular structures that showed apparent absorption and refraction properties were obtained. Conclusions: By using an intense monochromatic radiation beam from a synchrotron, we were able to image microscopic structures of the leporine optic nerve and surrounding tissues using both diffraction enhanced and CT planar imaging techniques. As far as we know, we are the only synchrotron research group in the world attempting to image the optic nerve, and the work is highly experimental and preliminary. We will continue to refine our methods and techniques of image acquisition. Supported by: Saskatchewan Health Research Foundation. Disclosure: Dr. Atkins has nothing to disclose. Dr. de Jager has nothing to disclose. Dr. Wiebe has nothing to disclose. Dr. Grahn has nothing to disclose. Dr. Chapman has nothing to disclose.

Dimensional characterization of selected elements in airborne PM10 samples using μ‐SRXRF

Micro synchrotron radiation X‐ray fluorescence (μ‐SRXRF) is a powerful spectroscopy technique that uses synchrotron radiation to induce X‐ray fluorescence in samples and provides exhaustive information on the micron and submicron scale. Among the major advantages of μ‐SRXRF spectroscopy are its nondestructive nature and that samples can usually be analyzed without pretreatment. At the ESRF (Grenoble, France) ID‐21 beamline, we examined PM10 samples collected at two sites in the Province of Trieste, Italy, in order to determine possible correlations among some low‐ to mid‐Z elements (S, Cl, K, Ca, Ti, V, Cr, Mn, and Fe), as well as investigated the possibility of using synchrotron radiation imaging techniques as a way to examine the granulometry of PM10 particles containing the various chemical elements. A consistent significant correlation between Ca and S has been found, which, coupled with the data obtained in a related study, indicates that a major part of the sulfate is present as CaSO4. Granulometry measurement via imaging techniques has shown that some elements such as Fe, Ca, and S are more amenable to this type of analysis than others. Additionally, the spatial homogeneity of a PM2.5 certified reference material (NIST SRM‐2783) has been investigated by analyzing four adjacent areas on the certified sample (total area 1 mm2). The certified reference material has shown a percentage relative standard deviation less than 7% for Al, Si, P, S, Cl, K, Ca, V, Cr, and Fe, and close to 17% for Ti and Mn. Copyright © 2011 John Wiley & Sons, Ltd.

Investigation of mineral distribution in bone by synchrotron X-ray fluorescence microscopy after tibolone therapy

Abstract Tibolone is a synthetic steroid with estrogenic, androgenic, and progestagenic properties used for the prevention of postmenopausal osteoporosis and treatment of climacteric symptoms. Tibolone shows almost no action on breast and endometrium, which are target-organs for estrogens and progesterone activity. The aim of this work was to investigate the spatial distribution of calcium and zinc minerals in the femoral head of ovariectomized rat in order to evaluate the effects of the long-term administration of tibolone. For that purpose X-ray microfluorescence was used with synchrotron radiation imaging technique which was performed at Brazilian Light Synchrotron Laboratory, Campinas, SP. Minerals were not homogeneously distributed in trabecular bone areas; a higher concentration of calcium in the trabecular regions at femoral heads was found in ovariectomized and tibolone-treated rats compared to ovariectomized and control groups.

Real time imaging on dendrite morphology evolution during alloy solidification under electric field

The evolution of dendrite morphology during the solidification of metallic alloy can not be in-situ observed since the metallic alloy is in optically opaque. It is also not possible to in-situ study the influence of electric current on dendritic growth behavior. By using synchrotron radiation imaging technique, we observe the evolution of dendrite morphology under an electric current. The imaging results indicate that the direct current can significantly suppress the dendritic growth. The dendrite tip turns to be round from sharp under direct current. With the increasing of current intensity, the dendrite tip splits due to the current crowding and solute pileup around the round tip. The pulsed electric current can significantly enhance the solidification rate and refine the primary and secondary dendrite arm spaces because of the thermal and mechanical shock around solid/liquid interface.

Evolution of dendrite morphology of a binary alloy under an applied electric current: Anin situobservation

Synchrotron radiation imaging technique was used to in situ observe the dendrite growth of a solidifying Sn-Bi binary alloy under a direct current (dc) electric field. By applying a dc (7-32 A/cm2), the dendrite branching was suppressed, the dendrite tip was modified to be round or flat, and no tertiary dendrite was found. With increasing dc density, the dendrite morphology was changed from columnar dendritic to equiaxed cellular to equiaxed dendritic. In particular, the primary dendrite branched following a tip-split manner in a higher intensity dc. The influence of dc on the evolution of dendrite morphology was discussed.