Multilayer Monochromator Research Articles

Development of 1-D X-ray beam diffuser for multilayer monochromator and its application to X-ray phase tomography

Development of 1-D X-ray beam diffuser for multilayer monochromator and its application to X-ray phase tomography

Mitigation of DMM-induced stripe patterns in synchrotron X-ray radiography through dynamic tilting.

In synchrotron X-ray radiography, achieving high image resolution and an optimal signal-to-noise ratio (SNR) is crucial for the subsequent accurate image analysis. Traditional methods often struggle to balance these two parameters, especially in situ applications where rapid data acquisition is essential to capture specific dynamic processes. For quantitative image data analysis, using monochromatic X-rays is essential. A double multilayer monochromator (DMM) is successfully used for this aim at the BAMline, BESSY II (Helmholtz Zentrum Berlin, Germany). However, such DMMs are prone to producing an unstable horizontal stripe pattern. Such an unstable pattern renders proper signal normalization difficult and thereby causes a reduction of the SNR. We introduce a novel approach to enhance SNR while preserving resolution: dynamic tilting of the DMM. By adjusting the orientation of the DMM during the acquisition of radiographic projections, we optimize the X-ray imaging quality, thereby enhancing the SNR. The corresponding shift of the projection during this movement is corrected in post-processing. The latter correction allows a good resolution to be preserved. This dynamic tilting technique enables the homogenization of the beam profile and thereby effectively reduces noise while maintaining high resolution. We demonstrate that data captured using this proposed technique can be seamlessly integrated into the existing radiographic data workflow, as it does not need hardware modifications to classical X-ray imaging beamline setups. This facilitates further image analysis and processing using established methods.

PINK: a tender X-ray beamline for X-ray emission spectroscopy.

A high-flux beamline optimized for non-resonant X-ray emission spectroscopy (XES) in the tender X-ray energy range has been constructed at the BESSY II synchrotron source. The beamline utilizes a cryogenically cooled undulator that provides X-rays over the energy range 2.1 keV to 9.5 keV. This energy range provides access to XES [and in the future X-ray absorption spectroscopy (XAS)] studies of transition metals ranging from Ti to Cu (Kα, Kβ lines) and Zr to Ag (Lα, Lβ), as well as light elements including P, S, Cl, K and Ca (Kα, Kβ). The beamline can be operated in two modes. In PINK mode, a multilayer monochromator (E/ΔE ≃ 30-80) provides a high photon flux (1014 photons s-1 at 6 keV and 300 mA ring current), allowing non-resonant XES measurements of dilute substances. This mode is currently available for general user operation. X-ray absorption near-edge structure and resonant XAS techniques will be available after the second stage of the PINK commissioning, when a high monochromatic mode (E/ΔE ≃ 10000-40000) will be facilitated by a double-crystal monochromator. At present, the beamline incorporates two von Hamos spectrometers, enabling time-resolved XES experiments with time scales down to 0.1 s and the possibility of two-color XES experiments. This paper describes the optical scheme of the PINK beamline and the endstation. The design of the two von Hamos dispersive spectrometers and sample environment are discussed here in detail. To illustrate, XES spectra of phosphorus complexes, KCl, TiO2 and Co3O4 measured using the PINK setup are presented.

Preparation and measurement of an x-ray Laue-type monochromator based on a WSi2/Si multilayer

The Laue-type multilayer monochromator (LMM) is a promising optical element with a small size and high efficiency in a synchrotron radiation facility. By the dynamical diffraction theory, using DC magnetron sputtering technology, an LMM with a total thickness of 47 µm and a periodic thickness of 4.7 nm WSi2/Si multilayer at 26 keV is designed and fabricated. During the preparation, the total number of layers is up to 20000, and every 300th layer of Si is replaced by WSi2 as the marker, so the multilayer is divided into 67 areas. The cross section of the multilayer is measured by a scanning electron microscope (SEM), and the marker region thickness error is 0.28% (RMS). The diffraction test experiment of the LMM is carried out at the Shanghai synchrotron radiation facility (SSRF). The 1st-order peak angle is 5.05 mrad, and the efficiency is 75.0%, which is close to the theoretical calculation result of 5.1 mrad and 79.1%. The Darwin width of the LMM is 0.17 mrad which is equal to the theoretical calculation. Based on the Bragg’s diffraction equation, the energy resolution (ΔE/E) is 3.3%.

Investigate the Possibility of Using Phosphorescence in Clinical Oncology as an Early Prognostic Test in Detecting Brain Carcinogenesis

Phosphorescence is considered one of the non-invasive glioblastoma testing methods based on studying molecular energy and the metabolism of L-tryptophan (Trp) through KP, which provides essential information on regulating immunity and neuronal function. This study aimed to conduct a feasibility study using phosphorescence in clinical oncology as an early prognostic test in detecting Glioblastoma. This study was conducted on 1039 patients who were operated on with follow-up between January 1, 2014, and December 1, 2022, and retrospectively evaluated in participating institutions in Ukraine (the Department of Oncology, Radiation Therapy, Oncosurgery, and Palliative Care at the Kharkiv National Medical University). Method of protein phosphorescence detection included two steps. During the first step, of luminol-dependent phosphorescence intensity in serum was carried out after its activation by the light source, according to the spectrofluorimeter method, as follows. At a temperature of 30 °C, serum drops were dried for 20 min to form a solid film. After that, we put the quartz plate with dried serum in a phosphoroscope of luminescent complex and measured the intensity. With the help of Max-Flux Diffraction Optic Parallel Beam Graded Multilayer Monochromator (Rigaku Americas Corporation) following spectral lines as 297, 313, 334, 365, 404, and 434 nm were distinguished and absorbed by serum film in the form of light quantum. The monochromator exit split width was 0.5 mm. Considering the limitations of each of the non-invasive tools currently available, phosphorescence-based diagnostic methods are ideally integrated into the NIGT platform: a non-invasive approach for visualizing a tumor and its main tumor characteristics in the spatial and temporal order. Because trp is present in virtually every cell in the body, these fluorescent and phosphorescent fingerprints can be used to detect cancer in many different organs. Using phosphorescence, it is possible to create predictive models for GBM in both primary and secondary diagnostics. This will assist clinicians in selecting the appropriate treatment option, monitoring treatment, and adapting to the era of patient-centered precision medicine.

X-ray scattering at beamline BL2 of DELTA: Studies of lysozyme-lysozyme interaction in heavy water and structure formation in 1-hexanol

The experimental station of the bending magnet beamline BL2 of the Dortmund Synchrotron Radiation Source DELTA has been reconstructed in order to enable small-angle X-ray scattering and wide-angle scattering studies with monochromatic beam. By using a multilayer monochromator with a bandwidth of 1.5%, it is possible to reach a photon energy of 12 keV at sufficiently high photon fluxes. The beamline layout is described and the experimental capabilities are discussed by giving two examples of typical experiments: (i) A dense lysozyme solution is studied using small-angle X-ray scattering in order to reveal to influence of pressure on the protein-protein interaction with heavy water as solvent. (ii) The dependency of the hydrogen-bond mediated structure formation on temperature and pressure is investigated in liquid 1-hexanol by wide-angle X-ray scattering.

Demonstration of the X-ray imaging capabilities of the newly installed multilayer monochromator at SPring-8 BL20B2

Double multilayer monochromators (DMMs) for 40 keV and 110 keV have been installed at BL20B2 in SPring-8. The DMMs provide X-rays with a few percent bandwidths at those energies. The flux density of the X-rays is more than several hundred times higher than that of monochromatic X-rays with a silicon double crystal monochromator, which enables us to perform high-speed X-ray imaging with a large field of view and high spatial resolution X-ray imaging in those high-energy X-rays. Here characteristics of DMMs and some demonstrations of X-ray imaging using the high flux density beams are shown.

A new beamline for hard X-ray tomographic microscopy at the Spanish Synchrotron ALBA

The BL31-FaXToR is a new beamline currently under construction at the third generation synchrotron facility ALBA, dedicated to hard x-ray micro-tomography. The beamline will provide the opportunity to perform 3D imaging within sub-seconds time resolution, working under mono- or white-beam conditions. A dual detection system is foreseen at the top of an innovative end-station design in order to perform fast imaging with a multi-scale approach. In this paper, we provide an overview of the new beamline design and of the expected performances. Raytracing and phase-contrast imaging simulations have been used to optimize the optical design. The beamline will be fed by a 2.5T multipole wiggler with a critical energy of 14.7 keV. A double multilayer monochromator (DMM) covers an energy range between 8 to 50 keV with a bandwidth up to 3.5%. The DMM crystals can be shifted out of the beam path to operate in filtered white beam modality with higher energies spanning from 30 to 70 keV. Multiple filtering configurations will be used to optimize the spectra according to the specific experimental settings. The beamline will serve different scientific communities, including material science, biomedical, paleontology, earth science, cultural heritage etc. FaXToR is expected to start user operations by the beginning of 2024.

Background Pressure Induced Structural and Chemical Change in NiV/B4C Multilayers Prepared by Magnetron Sputtering

NiV/B4C multilayers with a small d-spacing are suitable for multilayer monochromator working at a photon energy region from 5 to 8 keV, or photon energy region from 10 to 100 keV. To investigate the influence of background pressure during fabrication, NiV/B4C multilayers with a d-spacing of 3.0 nm were fabricated by magnetron sputtering with different background pressures. The grazing incidence x-ray reflectivity (GIXR) and transmission electron microscopy (TEM) measurement illustrated the structural change that happened in NiV/B4C multilayers when background pressure is high. The electron dispersive x-ray spectroscopy (EDX) of NiV/B4C multilayer deposited with a high background pressure suggests a gradient distribution of oxygen, which corresponds to the gradient thickness change. The detailed x-ray absorption near edge spectroscopy (XANES) comparison of NiV/B4C multilayers, NiV coating, and B4C coating showed the chemical state change induced by background pressure. We concluded that during the deposition, vanadium oxide promoted the oxidation of boron. In order to fabricate a good performance of NiV/B4C multilayers, the background pressure needs lower than 1 × 10−4 Pa.

Optimizing the energy bandwidth for transmission full-field X-ray microscopy experiments.

Full-field transmission X-ray microscopy (TXM) is a very potent high-resolution X-ray imaging technique. However, it is challenging to achieve fast acquisitions because of the limited efficiency of the optics. Using a broader energy bandwidth, for example using a multilayer monochromator, directly increases the flux in the experiment. The advantage of more counts needs to be weighed against a deterioration in achievable resolution because focusing optics show chromatic aberrations. This study presents theoretical considerations of how much the resolution is affected by an increase in bandwidth as well as measurements at different energy bandwidths (ΔE/E = 0.013%, 0.27%, 0.63%) and the impact on achievable resolution. It is shown that using a multilayer monochromator instead of a classical silicon double-crystal monochromator can increase the flux by an order of magnitude with only a limited effect on theresolution.

Design, performance, and utilization of the Low-Energy X-ray Reflectometer at DTU space

A state-of-the-art compact Low-Energy X-ray Reflectometer is in operation at DTU Space and is used to characterize x-ray coatings for the optics of future spaceborne and ground-based telescopes. The reflectometer is housed in a vacuum chamber and operates at 1.487 keV, complimenting an existing 8.048 keV reflectometer. With a microfocus source and plane-parabolic Kirkpatrick–Baez mirrors, the 0.5-mm wide beam is collimated to <0.75 arcmin. An actively cooled 2D CCD yields sample alignment precision of 26 μm in linear position and 0.18 arcmin in angle. A multilayer monochromator provides a peak reflectance of 43.5% and beam purity > 99 % . The reflectometer has a 2θ range of 0 deg to 35 deg and dynamic range up to eight orders of magnitude. Techniques are demonstrated to investigate the sample surface morphology and we show the system’s capability to detect the presence of atmospheric contaminants on coated mirrors.

Surface and interface characterization of Ru/C/Ru trilayer structure using grazing incidence X‐ray reflectivity and X‐ray fluorescence

In 8‐ to 20‐keV photon energy region, ruthenium and carbon thin films are used in multilayer monochromators. In the present study, this material combination is explored for X‐ray waveguide applications in hard X‐ray region. The structural parameters (thickness of each layer) of Ru/C/Ru waveguide structure are optimized to get maximum intensity enhancement of fundamental mode inside carbon guiding layer. A sample with optimized structural parameters is deposited using ion beam sputtering (IBS) technique and characterized using X‐ray reflectivity (XRR) and grazing incidence X‐ray fluorescence (GIXRF) techniques. The analysis suggests that the density of bottom Ru layer and carbon guiding layer is close to bulk density (~97% for Ru and ~95% for carbon), whereas density of top Ru layer is slightly lower (~93% of bulk density). A ~10% of thickness variation in top cladding layer along with marginal change in layer density deteriorate field enhancement in TE0 mode by more than three times. Effect of thickness and density variation on waveguide (Ru [7 nm]/C [18 nm]/Ru [20 nm]) performance is discussed.

Beamline B21: high-throughput small-angle X-ray scattering at Diamond Light Source.

B21 is a small-angle X-ray scattering (SAXS) beamline with a bending magnet source in the 3 GeV storage ring at the Diamond Light Source Ltd synchrotron in the UK. The beamline utilizes a double multi-layer monochromator and a toroidal focusing optic to deliver 2 × 1012 photons per second to a 34 × 40 µm (FWHM) focal spot at the in-vacuum Eiger 4M (Dectris) detector. A high-performance liquid chromatography system and a liquid-handling robot make it possible to load solution samples into a temperature-controlled in-vacuum sample cell with a high level of automation. Alternatively, a range of viscous or solid materials may be loaded manually using a range of custom sample cells. A default scattering vector range from 0.0026 to 0.34 Å-1 and low instrument background make B21 convenient for measuring a wide range of biological macromolecules. The beamline has run a full user programme since 2013.

Operation of a bending magnet beamline in large energy bandwidth mode for non-resonant X-ray emission spectroscopy

Two new operation modes, “pink beam” excitation, which has the energy bandwidth defined by X-ray mirrors and filters, and “broadband beam”, where the energy bandwidth is defined by the reflection from a multilayer monochromator, were implemented at the SuperXAS beamline of the Swiss Light Source (SLS). These setups allow measuring non-resonance X-ray emission spectra (XES) with 2–3 orders of magnitude higher incident flux than non-resonant XES measurements with a monochromatic incident beam. For the broadband beam mode, a Mo/Si multilayer structure was designed, with which the energy can be tuned in the 5–17 keV range. The multilayer demonstrates a relatively large energy bandwidth of 4 ± 0.2% through the whole energy range and a reflectivity of 23–60%, which increases with energy. We show that by using pink beam mode one can investigate the electronic structure of photocatalytic intermediates through time-resolved core-to-core XES experiments of diluted samples with a concentration of the element of interest of ~1 mM. Broadband beam mode is optimal for valence-to-core XES experiments and allow to avoid the excitation of additional KLβ satellites that can complicate the interpretation of spectra.

The Diamond I13 full-field transmission X-ray microscope: a Zernike phase-contrast setup for material sciences

The I13 transmission X-ray microscope at Diamond Light Source (DLS) has been designed to cover a broad range of energies and field of views. The beamline operates on an undulator source, and a multilayer monochromator can be used to work at a larger bandwidth to enable faster acquisitions. The experimental design includes large working distances for the optics to allow installing in situ sample environments. This paper presents the current state of the experimental system and shows some of the latest results.

Radiation shielding analysis of the concrete hutch of a long beamline of the Advanced Photon Source Upgrade project

The radiation shielding analysis of the external concrete enclosure of a feature long beamline of the Advanced Photon Source Upgrade project is described in this work. The beamline has 2 undulators that can operate in two different configurations and the source terms are estimated for the worst configuration using the SRW code in the OASYS package as well as the STAC8 code. The shielding analysis is carried out using the STAC8 code, and for the case of pink beam, with the FLUKA code also. Effective dose rates on contact with the outside surface of the concrete walls for pink, reflected full spectrum and monochromatic beams are calculated. For the monochromatic beams, 2 sets of discrete bandwidths (BW) from the Double Crystal Monochromator (DCM) and the full reflectance of the Double Multilayer Monochromator (DMM) are used. Further, due to the size of the direct beam and the energy domain of interest in the direct and scattered fields, the importance of the equivalent dose to the lens of the eye is discussed with respect to the shielding calculations of such facilities. The dose rates outside the concrete hutch in the lateral directions calculated using STAC8 is about 50% higher than the FLUKA results for the case of pink beam but may be considered as a reasonable agreement due to the differences in the calculational methodologies. Those dose rates in the lateral and forward directions are higher for the pink beam to allow full occupancy from the radiation protection point of view. For the full spectrum after 3 reflections, the effective dose rates are less than 0.5 μSv/h in the lateral direction but is higher in the forward region below about 22° with respect to the beam direction. For the DCM beams, except for the scenario with one mirror and 0.1%BW, all dose rates are less than 0.5 μSv/h outside the concrete hutch in the lateral directions. Here, the higher harmonics are what contributes to the dose outside the shield and the bandwidths assumed to derive the photon flux thus becomes important. The dose rates with the DMM are generally lower compared to the 0.1% BW DCM beam but are higher than the results obtained with XOP calculated bandwidths.

Full-field spectroscopic measurement of the X-ray beam from a multilayer monochromator using a hyperspectral X-ray camera.

Multilayer monochromator devices are commonly used at (imaging) beamlines of synchrotron facilities to shape the X-ray beam to relatively small bandwidth and high intensity. However, stripe artefacts are often observed and can deteriorate the image quality. Although the intensity distribution of these artefacts has been described in the literature, their spectral distribution is currently unknown. To assess the spatio-spectral properties of the monochromated X-ray beam, the direct beam has been measured for the first time using a hyperspectral X-ray detector. The results show a large number of spectral features with different spatial distributions for a [Ru, B4C] strip monochromator, associated primarily with the higher-order harmonics of the undulator and monochromator. It is found that their relative contributions are sufficiently low to avoid an influence on the imaging data. The [V, B4C] strip suppresses these high-order harmonics even more than the former, yet at the cost of reduced efficiency.

In situ GISAXS study on the temperature-dependent performance of multilayer monochromators from the liquid nitrogen cooling temperature to 600 °C

With the extensive demands of high-flux beamlines for current or planned synchrotron radiation sources, it is important to use multilayer monochromators for beamlines with insertion devices to select required quasi-monochromatic beams. Few studies have reported the interface evolution of multilayer monochromators in the liquid nitrogen (LN2) cooling environment under intense white beam irradiation. In this research, an in situ grazing-incidence small-angle X-ray scattering (GISAXS) setup was designed to monitor different interface characteristics of Ru/C, Cr/C, W/Si, and Ni/Ti multilayers from the LN2 temperature to 600 °C. The temperature treatment was executed in three steps — (i) the long-term low-temperature treatment, (ii) the quick temperature variation treatments, and (iii) the high-temperature treatment. A surface profiler was also used to determine the lower-frequency surface roughness after different temperature treatments. The temperature-dependent performances of multilayers were analyzed along the layer deposition direction and the out-of-plane direction. Scattering along the deposition direction reveals different interface features of the multilayers based on their thermal expansions. The power spectral density curve fitting proves that the fractal exponent is very sensitive to temperature change. Most of multilayers have a lower fractal exponent at the LN2 temperature. Moreover, clear interfacial changes were observed in Ru/C and Ni/Ti multilayers during high-temperature treatments.

Synchrotron-Based Characterization of Perfluorinated Sulfonic-Acid Ionomers

Perfluorinated sulfonic-acid (PFSA) ion-conducting polymers (ionomers) serve as both a binder and active ion-transport material in electrochemical energy-conversion electrodes including fuel cells, electrolyzers, and redox-flow batteries. Within the catalyst layer of these devices, ionomer shuttles ionic and liquid or gaseous species to/from catalytic sites.1-2 Optimizing the multi-functional role that PFSA ionomers play is crucial to developing next generation devices, and, to do so, the underlying fundamental structure-property relationships of these materials must first be established. Reducing the complex heterogeneous environment of catalyst layers down to representative model systems enables probing these relationships in a systematic and fundamental manner. To accomplish this effort, we spin-cast thin films of Nafion and 3M ionomer chemistries, including multi-acid side chains, across a range of thicknesses and processing conditions. Synchrotron-based x-ray scattering and spectroscopy, and advanced analysis of the collected data, is employed to characterize the phase-separated nano-structure of PFSA thin films. Results show the universality of confinement effects across chemistries, and how processing conditions modify the chemistry-confinement interplay and impact structure-function relationships. X-ray characterization is carried out in both ambient and humidified environment, in-situ, to determine the nanostructural changes in ionomer film in response to environment. These structural investigations are correlated to thermodynamic swelling properties using ellipsometry to identify factors controlling ionomer transport functionality in electrode structure of energy conversion devices. AcknowledgmentsWe thank Mike Yandrasits and Andrew Haug of 3M for providing ionomers and helpful discussions. This research used beamline 7.3.3 of the Advanced Light Source, which is a DOE Office of Science User Facility under contract no. DE-AC02-05CH11231.3 The study was funded under the Fuel Cell Performance and Durability Consortium (FC-PAD) funded by the Energy Efficiency and Renewable Energy, Fuel Cell Technologies Office, of the U.S. Department of Energy under contract number DE-AC02- 05CH11231. References Mauritz, K. A.; Moore, R. B., State of understanding of Nafion. Chemical reviews 2004, 104 (10), 4535-4586.Kusoglu, A.; Weber, A. Z., New Insights into Perfluorinated Sulfonic-Acid Ionomers. Chemical Reviews 2017, 117 (3), 987-1104.Alexander, H.; Wim, B.; James, G.; Eric, S.; Eliot, G.; Rick, K.; Alastair, M.; Matthew, C.; Bruce, R.; Howard, P., A SAXS/WAXS/GISAXS Beamline with Multilayer Monochromator. Journal of Physics: Conference Series 2010, 247 (1), 012007.

Synchrotron based absorption edge tomography for the analysis of 3D printed polymer embedded MOF

Absorption edge tomography (AET), also known as differential tomography at absorption edges, is a method which exploits the sudden change of the attenuation coefficient, when the photon energy crosses the absorption edge of an element [1]. Synchrotron radiation is the best source for absorption edge tomography, because of its small bandwidth, high intensity and easily adjustable photon energy [2]. The synchrotron beamline BAMline at the synchrotron radiation facility BESSY II in Berlin, which is operated by the Bundesanstalt für Materialforschung und -prüfung (BAM), provides a monochromatized beam in a photon energy range from 5 keV up to 80 keV with a bandwidth of 2%, when the double multilayer monochromator is used [3]. Together with the microtomography setup, this enables differential tomography with submicron resolution at the K edge of the elements [4] from chromium up to the lanthanides, and up to uranium, when the L edges are used as well. In this work, mechanochemically synthesized metal-organic framework (MOF) material HKUST-1 in combination with acrylonitrile- butadiene styrene (ABS) polymer was used to form a polymer MOF composite material by a simple extruder. This composite filament was used for 3D printing. Absorption edge tomography facilitated the evaluation of the 3D distribution of the MOF material both in the filament and the resultant printed sample up to μm resolution. Our very first data indicate, that HKUST-1 is mainly homogeneously dispersed in both polymer bulk materials. In addition, a few clusters having significantly higher Cu concentration were found. AET in combination with data fusion also allows for the calculation of the MOF amount located on the external polymer surface.