X-ray Microbeam Research Articles

Synchrotron X-Ray Analysis and Morphology Evidence for Stereo-Assemblies of Periodic Aggregates in Poly(3-hydroxybutyrate) with Unusual Photonic Iridescence.

3D morphology of poly(3-hydroxybutyrate) (PHB), crystallized in the presence of diluents of poly(1,3-trimethylene adipate) and poly(ethylene oxide), is probed using a novel approach coupled with selective etching. For interpreting the mechanisms of crystal periodic aggregation, various microscopic techniques and synchrotron microbeam X-ray analysis are used to observe the top surface in connection with the 3D crystal assemblies. Periodic grating architectures, with the cross-bar pitch exactly matching with the optical band spacing, are proved in banded PHB. The crystals under the ridge branch out to spawn finer crystals orienting/bending horizontally underneath the valley band, repeating till species drainage or impingement. The grating structure in the banded PHB resembles many nature's iridescence crystals and is further proved by photonic reflection results as a critical breakthrough novel finding.

Spatial association between platinum minerals and magmatic sulfides imaged with the Maia Mapper and implications for the origin of the chromite-sulfide-PGE association

ABSTRACT The spatial association between Pt minerals, magmatic sulfides, and chromite has been investigated using microbeam X-ray fluorescence (XRF) element mapping and the Maia Mapper. This lab-based instrument combines the Maia parallel energy dispersive (ESD) detector array technology with a focused X-ray beam generated from a liquid metal source. It proves to be a powerful technique for imaging Pt distribution at low-ppm levels on minimally prepared cut rock surfaces over areas of tens to hundreds of square centimeters, an ideal scale for investigating these relationships. Images of a selection of samples from the Bushveld Complex and from the Norilsk-Talnakh ore deposits (Siberia) show strikingly close association of Pt hotspots, equated with the presence of Pt-rich mineral grains, with magmatic sulfide blebs in all cases, except for a taxitic low-S ore sample from Norilsk. In all of the Bushveld samples, at least 75% of Pt hotspots (by number) occur at or within a few hundred microns of the outer edges of sulfide blebs. In samples from the leader seams of the UG2 chromitite, sulfides and platinum hotspots are also very closely associated with the chromite seams and are almost completely absent from the intervening pyroxenite. In the Merensky Reef, the area ratio of Pt hotspots to sulfides is markedly higher in the chromite stringers than in the silicate-dominated lithologies over a few centimeters either side. We take these observations as confirmation that sulfide liquid is indeed the prime collector for Pt and, by inference, for the other platinum group elements (PGEs) in all these settings. We further propose a mechanism for the sulfide-PGE-chromite association in terms of in situ heterogeneous nucleation of all these phases coupled with transient sulfide saturation during chromite growth and subsequent sulfide loss by partial re-dissolution. In the case of the amygdular Norilsk taxite, the textural relationship and high PGE/S ratio is explained by extensive loss of S to an escaping aqueous vapor phase.

In Situ Synchrotron X-ray Micro-Diffraction Investigation of Elastic Strains in Laminated Ti-Al Composites

Spatially resolved elastic strains in the bulk interior of a laminated Ti-Al metal composite were studied during in situ tensile loading at strains up to 1.66% by a synchrotron-based micro-diffraction technique, namely differential aperture X-ray microscopy (DAXM). For both Al and Ti grains, deviatoric elastic strains were estimated based on polychromatic X-ray microbeam diffraction, while lattice strains along the normal direction of the tensile sample were directly measured using monochromatic X-ray microbeam diffraction. The estimated deviatoric strains show large spatial variations, and the mean values are consistent with the external loading conditions, i.e., increasing tensile strain along the tensile direction and increasing compressive strain along the sample normal with increasing loading. The directly measured lattice strains also show large spatial variations, although the magnitude of this variation is smaller than that for the estimated deviatoric strain. The directly measured lattice strains in Ti grains are largely consistent with the external loading, whereas those in Al grains are in contradiction with the external loading. The causes of the experimental results are discussed and related to both the laminated microstructure of the composite material and the limitations of the techniques.

Field size effects on DNA damage and proliferation in normal human cell populations irradiated with X-ray microbeams

To clarify the health risks of internal radiation exposure, it is important to investigate the radiological effects of local exposure at cell levels from radioactive materials taken up by organs. Focusing on the response of cell populations post-irradiation, X-ray microbeams are very effective at reproducing the effects of local exposure within an internal exposure in vitro. The present study aims to clarify the effects of local exposure by investigating the response of normal human cell (MRC-5) populations irradiated with X-ray microbeams of different beam sizes to DNA damage. The populations of MRC-5 were locally irradiated with X-ray microbeams of 1 Gy at 0.02–1.89 mm2 field sizes, and analyzed whether the number of 53BP1 foci as DSB (DNA double strand break) per cell changed with the field size. We found that even at the same dose, the number of DSB per cell increased depending on the X-irradiated field size on the cell population. This result indicated that DNA damage repair of X-irradiated cells might be enhanced in small size fields surrounded by non-irradiated cells. This study suggests that X-irradiated cells received some signal (a rescue signal) from surrounding non-irradiated cells may be involved in the response of cell populations post-irradiation.

X-ray microbeam characterisation of crystalline defects in small pixel GaAs:Cr detectors

A newly supplied 80 × 80 chromium compensated GaAs sensor with a matrix of 80 × 80 pixels on a 250 μm pixel pitch has been characterised utilising microbeam mapping techniques at the Diamond Light Source. The GaAs:Cr sensor was mounted to a HEXITEC DAQ system before raster scanning an X-ray beam with area 25 × 25 μm2 in steps of 25 μm, providing sub-pixel resolution spectroscopic imaging. Scans were performed with incident X-ray energies ranging from 12 to 45 keV. Following processing of the data in MatLab 2019b an analysis of defects previously observed in etched GaAs wafers occurred. Findings indicate the presence of regions with reduced charge collection efficiency where up to 88% of incident events show significant charge loss, and changing charge carrier lifetimes across the sensor.

Unexpected Benefits of Multiport Synchrotron Microbeam Radiation Therapy for Brain Tumors

Simple SummaryWe unveiled the potential of an innovative irradiation technique that ablates brain cancer while sparing normal tissues. Spatially fractionating the incident beam into arrays of micrometer-wide beamlets of X-rays (MRT for Microbeam Radiation Therapy) has led to significantly increased survival and tumor control in preclinical studies. Multiport MRT versus conventional irradiations, for the same background continuous dose, resulted in unexpectedly high equivalent biological effects in rats that have not been achieved with any other radiotherapeutic method. These hallmarks of multiport MRT, i.e., minimal impact on normal tissues and exceptional tumor control, may promote this method towards clinical applications, possibly increasing survival and improving long-term outcomes in neuro-oncology patients.Delivery of high-radiation doses to brain tumors via multiple arrays of synchrotron X-ray microbeams permits huge therapeutic advantages. Brain tumor (9LGS)-bearing and normal rats were irradiated using a conventional, homogeneous Broad Beam (BB), or Microbeam Radiation Therapy (MRT), then studied by behavioral tests, MRI, and histopathology. A valley dose of 10 Gy deposited between microbeams, delivered by a single port, improved tumor control and median survival time of tumor-bearing rats better than a BB isodose. An increased number of ports and an accumulated valley dose maintained at 10 Gy delayed tumor growth and improved survival. Histopathologically, cell death, vascular damage, and inflammatory response increased in tumors. At identical valley isodose, each additional MRT port extended survival, resulting in an exponential correlation between port numbers and animal lifespan (r2 = 0.9928). A 10 Gy valley dose, in MRT mode, delivered through 5 ports, achieved the same survival as a 25 Gy BB irradiation because of tumor dose hot spots created by intersecting microbeams. Conversely, normal tissue damage remained minimal in all the single converging extratumoral arrays. Multiport MRT reached exceptional ~2.5-fold biological equivalent tumor doses. The unique normal tissue sparing and therapeutic index are eminent prerequisites for clinical translation.

Assessing the microscale heterogeneity in Standard Reference Material 4600 Surrogate Post-detonation Urban Debris

Nondestructive microbeam X-ray fluorescence (μXRF) spectrometry has been used to investigate the elemental microheterogeneity in a nuclear forensics reference material (RM), NIST SRM 4600 Surrogate Post-detonation Urban Debris. Using a principal component analysis (PCA) model, results indicate the majority of elements appear homogeneous; however, zinc (Zn) exhibits microscale heterogeneity for this SRM. To minimize contributions to the measurement uncertainty from elemental microheterogeneity, a minimum sample mass of 24 mg is recommended for analysis.

Influence of substrate misorientation on the emission and waveguiding properties of a blue (In,Al,Ga)N laser-like structure studied by synchrotron radiation microbeam X-ray diffraction

In this work, we study how an epitaxial laser-like (or superluminescent diode-like) structure is modified by intentional changes of the substrate misorientation in the range of 0.5°–2.6°. The 40 μm × 40 μm test structure with misorientation profiling was fabricated using multilevel photolithography and dry-etching. The local structural parameters were measured by synchrotron radiation microbeam X-ray diffraction, with the sampling area of below 1 μm × 1 μm . We directly obtained the relation between the misorientation and indium content in the quantum well, changing from 9% to 18%, with a high resolution (small misorientation step). We also show a good agreement of local photoluminescence emission wavelength with simulation of transition energy based on synchrotron radiation microbeam X-ray diffraction (SR-XRD) data and estimated Stokes shift. We observe that the substrate misorientation influences also the InGaN waveguide and AlGaN cladding composition. Still, we showed through simulation of the optical confinement factor of a full laser diode structure that good light guiding properties should be preserved in the whole misorientation range studied here. This proves the usefulness of misorientation modification in applications like broadband superluminescent diodes or multicolor laser arrays.

Inter-particle structural fluctuation of Prussian blue analogue as investigated by X-ray microbeam diffraction

The X-ray microbeam diffraction from each particle leads to a deeper structural characterization, i.e. inter-particle structural fluctuation, of powdery compound. Here, we performed X-ray microbeam diffractions of Na x Co1−z Ni z [Fe(CN)6] y at BL40XU beamline of SPring-8. In the whole region of z, the inter-particle structural fluctuation is negligible in the as-grown powder. We found that the average () of the spacing (d 012) of the (012) plane decreases with X-ray irradiation time (t). The standard deviation (σ) of d 012 steeply increases with t from 0.006 Å at t = 1 s to 0.031 Å at t = 60 s, indicating that inter-particle structural fluctuation is induced by the X-ray irradiation.

Artisanal ceramic factories using wood combustion: A nanoparticles and human health study

The ceramics industry, resulting from developments of modern compounds, is a segment of great influence in worldwide sustainability. Artisanal ceramic factories based on wood combustion have significant risks for the creation and discharge of atmosphere nanoparticles (NPs) and ultra-fine particles (UFPs). At present, there is insufficient recognition on the influence of engineered-NPs on the atmosphere and health. Real improvements are indispensable to diminish contact with NPs. The present study demonstrates the main NPs and UFPS present in an area of intense artisanal wood-combustion ceramic manufacturing. Particulate matter was sampled for morphological, chemical, and geochemical studies by sophisticated electron microbeam microscopy, X-Ray Diffraction, and Raman spectroscopy. From NPs configuration (<10 nm) we identify nucleation. Several amorphous NPs (>10 nm) were produced around the studied artisanal ceramic factories. This study presents an indication of the recent information on population and work-related contact to NPs in the artisanal ceramic factories and their influence on health.

X-ray microbeam diffraction in a crystal.

Using the formalism of dynamical scattering of spatially restricted X-ray fields, the diffraction of a microbeam in a crystal with boundary functions for the incident and reflected amplitudes was studied in the case of geometrical optics and the Fresnel approximation (FA). It is shown that, for a wide front of the X-ray field, the angular distributions of the scattered intensity in the geometrical optics approximation (GOA) and the FA are approximately the same. On the other hand, it is established that, for a narrow exit slit in the diffraction scheme, it is always necessary to take into account the X-ray diffraction at the slit edges. Reciprocal-space maps and the distribution of the diffraction intensity of the microbeam inside the crystal were calculated.

Speech intelligibility loss due to amyotrophic lateral sclerosis: the effect of tongue movement reduction on vowel and consonant acoustic features

ABSTRACT The purpose of this study was to identify aspects of impaired tongue motor performance that limit the ability to produce distinct speech sounds and contribute to reduced speech intelligibility in individuals with dysarthria secondary to amyotrophic lateral sclerosis (ALS). We analyzed simultaneously recorded tongue kinematic and acoustic data from 22 subjects during three target words (cat, dog, and took). The subjects included 11 participants with ALS and 11 healthy controls from the X-ray microbeam dysarthria database (Westbury, 1994). Novel measures were derived based on the range and speed of relative movement between two quasi-independent regions of the tongue – blade and dorsum – to characterize the global pattern of tongue dynamics. These “whole tongue” measures, along with the range and speed of single tongue regions, were compared across words, groups (ALS vs. control), and measure types (whole tongue vs. tongue blade vs. tongue dorsum). Reduced range and speed of both global and regional tongue movements were found in participants with ALS relative to healthy controls, reflecting impaired tongue motor performance in ALS. The extent of impairment, however, varied across words and measure types. Compared with the regional tongue measures, the whole tongue measures showed more consistent disease-related changes across the target words and were more robust predictors of speech intelligibility. Furthermore, these whole tongue measures were correlated with various word-specific acoustic features associated with intelligibility decline in ALS, suggesting that impaired tongue movement likely contributes to reduced phonetic distinctiveness of both vowels and consonants that underlie speech intelligibility decline in ALS.

Analytical Method of Sulfur Speciation of Volcanic Glass and Melt Inclusions using Soft X-ray Microbeam

Analytical Method of Sulfur Speciation of Volcanic Glass and Melt Inclusions using Soft X-ray Microbeam

Analyses of Trace Elements in Precious Corals as Indicators for Origin and Habitat Using SR X-ray Microbeams

Analyses of Trace Elements in Precious Corals as Indicators for Origin and Habitat Using SR X-ray Microbeams

Micro-beam X-ray Fluorescence Imaging for Indium Distributed at Cross Section of Hair Contamination Characteristics of Indium in Hair of Workers

Micro-beam X-ray Fluorescence Imaging for Indium Distributed at Cross Section of Hair Contamination Characteristics of Indium in Hair of Workers

Development of scanning X-ray fluorescence microscope using KB mirror and white synchrotron radiation at SAGA Light Source

A scanning X-ray fluorescence microscope that uses a Kirkpatrick-Baez (KB) mirror and white synchrotron radiation (SR) was developed for obtaining detailed elemental maps within a micro-meter order. The KB mirror is a total reflection mirror, and the white X-rays are focused at a focus point without chromatic aberration. Therefore, the proposed microscope can use strong white and/or pink SR and enable elemental mapping within a practical measurement time at small synchrotron facilities. A feasibility study on the developed microscope was performed by using white SR at the SAGA Light Source in Tosu, Japan. By using the developed microscope, an X-ray microbeam 1 μm in diameter was successfully formed, and a fine elemental map of a Cu mesh and a seed of eustoma were obtained.

Cell response analysis to synchrotron radiation X-ray microbeam cytoplasm limited irradiation

The cells responsible for cancer start their journey much like any other in the body. However, they grow uncontrollably through the body as a result of the accumulation of certain mutations. If left unchecked, cancer will impact on a number of the human body's key processes, leading, ultimately, to death. There are many challenges associated with treating this disease, but they generally stem from the difficulty in differentiating the disease from the host and the ability of even a few cells to survive, recover and return. The most common treatments generally combine surgery with some type of chemotherapy or radiotherapy. Chemotherapy utilises chemicals that kill fast-growing cells and thereby disproportionally affect the rapidly multiplying cancer cells. Radiotherapy targets the tumour with radiation to cause damage and cell death. Both have their advantages and disadvantages, and both are often not 100 per cent effective. To improve these treatments, it is necessary to understand more about their precise effects on cells and, particularly, what defences cells have against their effects. Senior Principal Researcher Dr Masao Suzuki of the National Institutes for Quantum and Radiological Science and Technology (QST) is utilising the considerable radiological resources of QST to investigate the effects of different types of radiation on cells under different conditions.

Revealing filler morphology in 3D-printed thermoset nanocomposites by scanning microbeam X-ray scattering

Abstract Room temperature direct-ink-write printing of epoxy-nanoclay-carbon fiber composites produces parts with high stiffness and strength. Establishing clear relationships between print parameters, filler orientation, and properties is difficult, in part owing to challenges in characterization. Here, we perform scanning microbeam X-ray scattering with 5 micrometer spatial resolution on cross-sections of printed parts with (a) epoxy-nanoclay composite and (b) epoxy-nanoclay-carbon fiber reinforced composite. The nanoclay morphology is directly visualized, illuminating the road geometry with far greater clarity than other techniques. Near the boundary of each road, the nanoclay platelets are preferentially oriented coplanar with the road boundary. Shear alignment within the nozzle during extrusion, and road-to-road shear upon deposition are two proposed factors leading to this orientation. In the sample containing carbon fiber, wide angle X-ray diffraction enables the mapping and visualization of the fibers directly onto the road geometry. The carbon fiber does not significantly affect the nanoclay morphology. Finally, from the small angle X-ray scattering map, we qualitatively reproduce a polarized optical microscope image, revealing that optical microscopy is capable of visualizing the large-scale road structure in these epoxy-nanoclay systems.

Characterising Ion-Irradiated FeCr: Hardness, Thermal Diffusivity and Lattice Strain

Ion-irradiated FeCr alloys are useful for understanding and predicting neutron damage in the structural steels of future nuclear reactors. Previous studies have largely focused on the structure of irradiation-induced defects, probed by transmission electron microscopy (TEM), as well as changes in mechanical properties. Across these studies, a wide range of irradiation conditions has been employed on samples with different processing histories, which complicates the analysis of the relationship between defect structures and material properties. Furthermore, key properties, such as irradiation-induced changes in thermal transport and lattice strain, are little explored.Here we present a systematic study of Fe3Cr, Fe5Cr and Fe10Cr binary alloys implanted with 20 MeV Fe3+ ions to nominal doses of 0.01 dpa and 0.1 dpa at room temperature. Nanoindentation, transient grating spectroscopy (TGS) and X-ray micro-beam Laue diffraction were used to study the changes in hardness, thermal diffusivity and strain in the material as a function of damage and Cr content. Our results suggest that Cr leads to an increased retention of irradiation-induced defects, causing substantial changes in hardness and lattice strain. However, thermal diffusivity varies little with increasing damage and instead degrades significantly with increasing Cr content in the material. We find significant lattice strains even in samples exposed to a nominal displacement damage of 0.01 dpa. The defect density predicted from the lattice strain measurements is significantly higher than that observed in previous TEM studies, suggesting that TEM may not fully capture the irradiation-induced defect population.

Targeted Nuclear Irradiation with an X-Ray Microbeam Enhances Total JC-1 Fluorescence from Mitochondria.

Several studies have demonstrated that mitochondria are critically involved in the pleiotropic manifestation of radiation effects. While conventional whole-cell irradiation compromises the function of mitochondria, the effects of subcellular targeted radiation are not yet fully understood. In this study, normal human diploid cells with cell-cycle indicators were irradiated using a synchrotron X-ray microbeam, and mitochondrial membrane potential was quantified by JC-1 over the 72-h period postirradiation. Cytoplasmic irradiation was observed to temporarily enlarge the mitochondrial area with high membrane potential, while the total mitochondrial area did not change significantly. Unexpectedly, cell-nucleus irradiation promoted a similar increase not only in the mitochondrial areas with high membrane potential, but also in those with low membrane potential, which gave rise to the apparent increase in the total mitochondrial area. Augmentation of the mitochondrial area with low membrane potential was predominantly observed among G1 cells, suggesting that nucleus irradiation during the G1 phase regulated the mitochondrial dynamics of the cytoplasm, presumably through DNA damage in the nucleus.