ALBA Synchrotron Research Articles

Comparison of synchrotron‐based ftir spectra in lens epithelial‐ and idiopathic epiretinal membrane‐ cells

Purpose: To determine the synchrotron radiation‐based FTIR microspectroscopy spectrum of lens capsules (LCs) from cataract surgery and that of idiopathic epiretinal membranes (iERMs) towards finding a possible causal relationship between lens fragments falling onto the posterior segment during phacoemulsification procedure and development of iERMs.Methods: LCs from cataract surgery and iERMs were collected from 5 patients. FTIR measurements were performed at the MIRAS beamline of the ALBA Synchrotron, Barcelona, Spain, and the complete bio‐macromolecular spectral information at cellular level (proteins, lipids, and nucleic acids) in the lens epithelium of LCs from cataract surgery and iERMs were evaluated and compared.Results: The FTIR spectra revealed several bands corresponding to the vibration of various groups associated with proteins, lipids, and nucleic acids, demonstrating the complex biochemical composition of the LCs and iERMs. Overall, the spectra of the LCs and iERMs were very similar, showing slight differences in the spectral region of the proteins, particularly in the Amide I, then in the carbonyl groups, and phosphate groups of DNA. Additionally, the lipid region showed differences in the spectral ratio between the LCs and iERMs, characterized by CH2 and CH3 bands.Conclusions: The FTIR spectra of lens epithelial cells on LCs and cells within the iERMs appeared similar, with slight differences in some spectral regions. It is possible that the lens fragments falling onto the retina during cataract surgery could contribute to the pathogenesis of iERMs.

Synchrotron-based infrared microspectroscopy unveils the biomolecular response of healthy and tumour cell lines to neon minibeam radiation therapy.

Radioresistant tumours remain complex to manage with current radiotherapy (RT) techniques. Heavy ion beams were proposed for their treatment given their advantageous radiobiological properties. However, previous studies with patients resulted in serious adverse effects in the surrounding healthy tissues. Heavy ion RT could therefore benefit from the tissue-sparing effects of minibeam radiation therapy (MBRT). To investigate the potential of this combination, here we assessed the biochemical response to neon MBRT (NeMBRT) through synchrotron-based Fourier transform infrared microspectroscopy (SR-FTIRM). Healthy (BJ) and tumour (B16-F10) cell lines were subjected to seamless (broad beam) neon RT (NeBB) and NeMBRT at HIMAC. SR-FTIRM measurements were conducted at the MIRAS beamline of ALBA Synchrotron. Principal component analysis (PCA) permitted to assess the biochemical effects after the irradiations and 24 hours post-irradiation for the different RT modalities and doses. For the healthy cells, NeMBRT resulted in the most dissimilar spectral signatures from non-irradiated cells early after irradiations, mainly due to protein conformational modifications. Nevertheless, most of the damage appeared to recover one day post-RT; conversely, protein- and nucleic acid-related IR bands were strongly affected by NeBB 24 hours after treatment, suggesting superior oxidative damage and nucleic acid degradation. Tumour cells appeared to be less sensitive to NeBB than to NeMBRT shortly after RT. Still, after one day, both NeBB and the high-dose NeMBRT regions yielded important spectral modifications, suggestive of cell death processes, protein oxidation or oxidative stress. Lipid-associated spectral changes, especially due to the NeBB and NeMBRT peak groups for the tumour cell line, were consistent with reactive oxygen species attacks.

Characterisation of SiC radiation detector technologies with synchrotron X-rays

To cope with environments with high levels of radiation, non-silicon semiconductors such as silicon carbide detectors are being proposed for instrumentation. 4H-SiC diodes for radiation detection have been fabricated in the IMB-CNM Clean Room, for which different strategies to define the electrical contact of the implants had been implemented, in an attempt to optimise the technology for, e.g., medical applications or low energy radiation detection, as the material choice can affect the sensitivity of the device. Among these technologies, it is included an epitaxially-grown graphene layer as part of the electrical contact. In this paper, a selection of four configurations of the IMB-CNM SiC diodes are characterised in terms of radiation detector response. Photodiode performance under 20 keV X-rays irradiation in the XALOC beam line at ALBA Synchrotron is presented. Over-responses in the range of 12–19% linked to the interaction of the radiation with the metallic layers are observed. A good uniformity response as well as a good linearity at 0 V bias is reported, even in the under-depleted devices. This work exemplifies the good performance of SiC detectors fabricated at IMB-CNM specifically for low-energy X ray characterization at high X-ray intensities.

Two-dimensional synchrotron beam characterization from a single interferogram

Double-aperture young interferometry is widely used in accelerators to provide a one-dimensional beam measurement. We improve this technique by combining and further developing techniques of nonredundant, two-dimensional, aperture masking, and self-calibration from astronomy. Using visible synchrotron radiation, tests at the ALBA synchrotron show that this method provides an accurate two-dimensional beam transverse characterization, even from a single 1 ms interferogram. The nonredundancy of the aperture mask in the technique enables it to be resistant to spatial phase fluctuations that might be introduced by vibration of optical components or in the laboratory atmosphere. Published by the American Physical Society 2024

L-cystine adsorption on a pyrite (100) surface exposed to O2 and CO2 atmospheres by near-ambient pressure X-ray photoelectron spectroscopy (NAP-XPS)

Pyrite surfaces were exposed to oxygen or carbon dioxide atmospheres in a controlled manner at different pressures at the NAPP end station of the CIRCE beamline at the ALBA Synchrotron Light Source to simulate various primitive terrestrial environments, confirming the occurrence of surface oxidation and characterise the chemical species formed. After preliminary gas pretreatment to prepare the substrate, the dimeric amino acid molecule L-cystine was dosed onto the pyrite substrate under UHV conditions, representing the first time that an amino acid was successfully sublimated and adsorbed in situ on a surface at the NAPP-CIRCE beamline. The intense nitrogen feature and molecular disulphide bridge as a molecular fingerprint, confirmed the successful adsorption of L-cystine on the pretreated pyrite surfaces under both O2 and CO2 atmospheres, although the oxidation process differed. Our results using near-ambient pressure X-ray photoelectron spectroscopy (NAP-XPS) at the ALBA synchrotron source help to clarify how different environments can favour or inhibit molecular adsorption and modify biomolecule-surface interactions. Furthermore, it could explain the high reactivity of pyrite surfaces to organic molecules, even after exposure to an oxidising atmosphere, thus inhibiting further reactions and provide insight relevant to the field of prebiotic chemistry.

Investigating the biochemical response of proton minibeam radiation therapy by means of synchrotron-based infrared microspectroscopy

The biology underlying proton minibeam radiation therapy (pMBRT) is not fully understood. Here we aim to elucidate the biological effects of pMBRT using Fourier Transform Infrared Microspectroscopy (FTIRM). In vitro (CTX-TNA2 astrocytes and F98 glioma rat cell lines) and in vivo (healthy and F98-bearing Fischer rats) irradiations were conducted, with conventional proton radiotherapy and pMBRT. FTIRM measurements were performed at ALBA Synchrotron, and multivariate data analysis methods were employed to assess spectral differences between irradiation configurations and doses. For astrocytes, the spectral regions related to proteins and nucleic acids were highly affected by conventional irradiations and the high-dose regions of pMBRT, suggesting important modifications on these biomolecules. For glioma, pMBRT had a great effect on the nucleic acids and carbohydrates. In animals, conventional radiotherapy had a remarkable impact on the proteins and nucleic acids of healthy rats; analysis of tumour regions in glioma-bearing rats suggested major nucleic acid modifications due to pMBRT.

Industrially relevant injection moulding apparatus for in situ time-resolving small-angle X-ray scattering measurements

This work presents the design and construction of an automated industrial injection moulding apparatus that can be used with a typical multi-user beamline such as the NCD-SWEET small-angle X-ray scattering at the ALBA Synchrotron Light Source. This apparatus is focused on developing an understanding of how the mould temperature and the injection temperature and pressure affect both the orientation and morphology of the semi-crystalline polymer used to fabricate the injected parts. The system design follows current industrial practice and enables the collection of time-resolved X-ray scattering data at several points within the mould cavity, so we can understand the 4D morphology. In this work we show the effectiveness of the equipment using some results from the injection moulding of a random copolymer of polypropylene and that it can be used with a more demanding material such as polyhydroxybutyrate. This can be seen as the first step toward a multiscale digital twin for injection moulding.

Large Language Model-Informed X-ray Photoelectron Spectroscopy Data Analysis

X-ray photoelectron spectroscopy (XPS) remains a fundamental technique in materials science, offering invaluable insights into the chemical states and electronic structure of a material. However, the interpretation of XPS spectra can be complex, requiring deep expertise and often sophisticated curve-fitting methods. In this study, we present a novel approach to the analysis of XPS data, integrating the utilization of large language models (LLMs), specifically OpenAI’s GPT-3.5/4 Turbo to provide insightful guidance during the data analysis process. Working in the framework of the CIRCE-NAPP beamline at the CELLS ALBA Synchrotron facility where data are obtained using ambient pressure X-ray photoelectron spectroscopy (APXPS), we implement robust curve-fitting techniques on APXPS spectra, highlighting complex cases including overlapping peaks, diverse chemical states, and noise presence. Post curve fitting, we engage the LLM to facilitate the interpretation of the fitted parameters, leaning on its extensive training data to simulate an interaction corresponding to expert consultation. The manuscript presents also a real use case utilizing GPT-4 and Meta’s LLaMA-2 and describes the integration of the functionality into the TANGO control system. Our methodology not only offers a fresh perspective on XPS data analysis, but also introduces a new dimension of artificial intelligence (AI) integration into scientific research. It showcases the power of LLMs in enhancing the interpretative process, particularly in scenarios wherein expert knowledge may not be immediately available. Despite the inherent limitations of LLMs, their potential in the realm of materials science research is promising, opening doors to a future wherein AI assists in the transformation of raw data into meaningful scientific knowledge.

Infrared microspectroscopy to elucidate the underlying biomolecular mechanisms of FLASH radiotherapy

Background:FLASH-radiotherapy (FLASH-RT) is an emerging modality that uses ultra-high dose rates of radiation to enable curative doses to the tumor while preserving normal tissue. The biological studies showed the potential of FLASH-RT to revolutionize radiotherapy cancer treatments. However, the complex biological basis of FLASH-RT is not fully known yet. Aim:Within this context, our aim is to get deeper insights into the biomolecular mechanisms underlying FLASH-RT through Fourier Transform Infrared Microspectroscopy (FTIRM). Methods:C57Bl/6J female mice were whole brain irradiated at 10 Gy with the eRT6-Oriatron system. 10 Gy FLASH-RT was delivered in 1 pulse of 1.8μs and conventional irradiations at 0.1 Gy/s. Brains were sampled and prepared for analysis 24 h post-RT. FTIRM was performed at the MIRAS beamline of ALBA Synchrotron. Infrared raster scanning maps of the whole mice brain sections were collected for each sample condition. Hyperspectral imaging and Principal Component Analysis (PCA) were performed in several regions of the brain. Results:PCA results evidenced a clear separation between conventional and FLASH irradiations in the 1800–950 cm−1 region, with a significant overlap between FLASH and Control groups. An analysis of the loading plots revealed that most of the variance accounting for the separation between groups was associated to modifications in the protein backbone (Amide I). This protein degradation and/or conformational rearrangement was concomitant with nucleic acid fragmentation/condensation. Cluster separation between FLASH and conventional groups was also present in the 3000–2800 cm−1 region, being correlated with changes in the methylene and methyl group concentrations and in the lipid chain length. Specific vibrational features were detected as a function of the brain region. Conclusion:This work provided new insights into the biomolecular effects involved in FLASH-RT through FTIRM. Our results showed that beyond nucleic acid investigations, one should take into account other dose-rate responsive molecules such as proteins, as they might be key to understand FLASH effect.

Development of fast BBA for Diamond Light Source

Beam-based alignment (BBA) is a standard tool at accelerators for aligning particle beams to the centre of quadrupole magnets. Traditional BBA measurements have been slow, potentially taking many hours for a whole machine. We have developed a tool, based on results previously reported at the ALBA synchrotron, that uses fast excitation of magnets to speed up measurements. We show the results of different measurement and analysis techniques in comparison to the currently used slow method.

Performance of high-temperature superconducting REBCO coated conductors under synchrotron irradiation for future circular colliders

The influence of medium-to-high energy synchrotron radiation (SR) (≈10–100 keV) produced by the ALBA Synchrotron Light Source on state-of-the-art REBCO coated conductors (CCs) has been studied to assess the feasibility of using high-temperature superconductors for the beam screen of future circular colliders. Long-term irradiation studies were conducted with ex-situ surface resistance testing by using a dielectric resonator. In addition, a cryogenic test system was established for in-situ measurements of the critical temperature and surface impedance of REBCO-CCs during synchrotron irradiation, with intensities similar to or above those generated by proton beams circulating in the vacuum chamber in the future circular collider hadron–hadron design. It is shown that the SR impact does not introduce any macroscopic defects that permanently alter the critical temperature or surface impedance of REBCO-CCs. However, the most significant effect of SR is a transient increase in the REBCO’s surface impedance. This effect is likely caused by heat, as the material returns to its original impedance values once the radiation exposure stops. The correlation between the time structure of the SR and the possibility of suppressing the Cooper pairing mechanism is also discussed.

(Invited) Core-Shell Fe3O4@CoFe2O4 Spinel Nanoparticles for the Oxygen Evolution Reaction in Alkaline Media

Transition metal oxides have attracted much attention as promising anode materials for anion exchange membrane water electrolysis (AEMWE). Herewith we introduce core-shell nanoparticles comprised of a Fe3O4 core and a CoFe2O4 shell as prospective catalysts for the oxygen evolution reaction (OER) at the cathode of an AEMWE. We show that confining the active component in a thin (~1-2 nm) shell and taking advantage from the core-shell synergistic interaction allows one to reach an exceptional OER activity of 2800 A at 1.65 V vs. RHE per gram of cobalt [1]. We further show that to correctly determine the OER activity, it is necessary to study the OER in a wide interval of the catalyst loadings [2].To shed light of the origin of the aforementioned synergistic effect between the core and the shell, the Fe3O4@CoFe2O4 nanoparticles were investigated using operando near edge X-ray absorption fine structure (NEXAFS) spectroscopy in a total electron yield (TYE) detection mode, under potential and during the OER conditions [3] . We documented a strong influence of the Fe3O4 core on the redox behavior of the CoFe2O4 shell under the OER conditions. Contrary to the previously studied Co3O4 anode, whose surface at high potentials has been shown to transform into CoOOH [4], the shell of the Fe3O4@CoFe2O4 nanoparticles maintains its spinel structure with Co(II) stabilized by the Fe(III) of the core. The results suggest the occurrence of a cation-redox OER mechanism involving cooperative redox behavior between Co and Fe atoms. It is remarkable that the core-shell structure is essentially preserved under the OER conditions.Figure 1. Left-hand side: cartoon showing the composition of the core-shell nanoparticle and charge transfer from Co to Fe occurring under positive polarization. Right-hand side: Fe L-edge difference spectra acquired at 1.2, 1.4 and 1.8 V vs RHE (the reference itself taken at 1.0 V vs. RHE). Reproduced from Ref. [3].Finally, we study the influence of the shell composition by replacing Co by Ni on the OER activity and stability of core-shell nanoparticles. Acknowledgements The authors are indebted to S. Hettler and R. Arenal of INMA (Zaragoza, Spain), S. Holdcroft of SFU (Vancouver, Canada) and J. Velasco-Vélez of Alba Synchrotron facility (Spain) for their cooperation. We thank the HZB für Materialien und Energie for the allocation of synchrotron radiation beamtime. Financial support from Jean-Marie-Lehn foundation is gratefully acknowledged.REFERENCES[1] L. Royer, S. Hettler, R. Arenal, T. Asset, B. Rotonnelli, A. Bonnefont, E. Savinova, B. Pichon, submitted.[2] L. Royer, J. Guehl, M. Zilbermann, T. Dintzer, C. Leuvrey, B. Pichon, E. Savinova, A. Bonnefont, submitted.[3] L. Royer, A. Bonnefont, T. Asset, B. Rotonnelli, J. Velasco-Vélez, S. Holdcroft, S. Hettler, R. Arenal, B. Pichon, E. Savinova, ACS Catalysis, https://doi.org/10.1021/acscatal.2c04512.[4] F. Reikowski, F. Maroun, I. Pacheco, T. Wiegmann, P. Allongue, J. Stettner, O. Magnussen, ACS Catal. 2019, 9 (5), 3811–3821; https://doi.org/10.1021/acscatal.8b04823. Figure 1

Property mapping of LDPE during 3D printing: evaluating morphological development with X-ray scattering

Direct digital manufacturing has been identified as one of the key tools of Industry 4.0 and it enables the creation of products directly through digital definition. Commonly known as additive manufacturing, it comprises a set of technologies that are expressively agile in small-scale productions and prototyping, in comparison to conventional mass manufacturing processes, such as injection molding of plastics. It streamlines mass customization, allows the production of highly complex objects, and has been broadly applied in several fields, from medical devices to the aerospace industry. Although a new era of design possibilities and accessibility was unveiled, most developments are focused on shape reproduction precision and the development of new feeding systems and materials. This work is focused on a shift in design for additive manufacturing, where the polymer properties, by means of the adjustment of the process conditions (extrusion rate, the write speed, and the nozzle temperature, among others), constitute a decision-making variable. In order to evaluate the morphology of semicrystalline polymers during extrusion-based 3D printing,in-situtime-resolving small and wide-angle X-ray scattering measurements were performed at the ALBA synchrotron light source in Barcelona (Spain). The goal of this research is to develop a material property mapping methodology during semicrystalline polymer melt extrusion-based 3D printing Some experiments were performed with low-density polyethylene, and we were able to confirm a correlation between the extrusion rate and writing speed of the printing with the level of preferred orientation of the chain folded lamellar crystals in the extrudate.

FeS2-Decorated Carbon NanoFiber as Solid Phase Conversion-Type Cathode for Li-S Batteries

A new cathode material, FeS2-decorated carbon nanofiber (CNF), is proposed for Li-S batteries. The structure and physicochemical properties of the material have been engineered to enhance the poor cycling stability typically displayed by sulfur composites. The composite material shows a complex architecture with a matrix of CNF hosting the sulfur and core-shell FeS2 nanoparticles acting as a catalyst for a solid phase conversion-type reaction. This cathode delivers high discharge capacities of 864, 798, 689, 595 and 455 mAhg−1 at C/10, C/5, C/2, 1C and 2C, respectively, with a stable capacity retention of 87% at 2C after 300 cycles. FeS2-decorated CNF has been characterised using several techniques, including in-situ battery measurements at the ALBA synchrotron facility and high-throughput microscopy, giving valuable insights into its charge/discharge reaction mechanism. The excellent performance obtained is combined with the use of just low-cost and abundant elements such as iron, sulfur and carbon, which makes this battery highly promising for the next generation of electrochemical energy storage devices.

ALBA Synchrotron and its future

The ALBA Synchrotron light source is the Spanish national facility, providing extended research capabilities and a wide range of state-of-the-art instrumentation to academic and industrial users of the Spanish and European Research Area since 2012. It includes ten operating beamlines, two beamlines in commissioning and two more in construction. JEMCA (Joint Electron Microscopy Center at ALBA), a center including advanced electron microscopes, developed in collaboration with partner institutions, has recently been inaugurated. The next years will be dedicated to exploit the existing instrumentation, and in parallel prepare the upgrade toward a fourth generation synchrotron source, by combining the partial substitution of the accelerators with the upgrade of the existing instrumentation, the addition of new cutting-edge beamlines, the development of further capabilities for automatization, simulation, prototyping, nanotechnology and advanced optics, and the extension of the infrastructure in the nearby plots, which will host the new long beamline end-stations and aim at being the seed of a science, technology and innovation park. The 2-year dark period is foreseen for the end of this decade. The status of the facility, few scientific highlights, and the plans for the future are described.

Correlative Cryo-imaging Using Soft X-Ray Tomography for the Study of Virus Biology in Cells and Tissues.

Viruses are obligate intracellular pathogens that depend on their host cell machinery and metabolism for their replicative life cycle. Virus entry, replication, and assembly are dynamic processes that lead to the reorganisation of host cell components. Therefore, a complete understanding of the viral processes requires their study in the cellular context where advanced imaging has been proven valuable in providing the necessary information. Among the available imaging techniques, soft X-ray tomography (SXT) at cryogenic temperatures can provide three-dimensional mapping to 25 nm resolution and is ideally suited to visualise the internal organisation of virus-infected cells. In this chapter, the principles and practices of synchrotron-based cryo-soft X-ray tomography (cryo-SXT) in virus research are presented. The potential of the cryo-SXT in correlative microscopy platforms is also demonstrated through working examples of reovirus and hepatitis research at Beamline B24 (Diamond Light Source Synchrotron, UK) and BL09-Mistral beamline (ALBA Synchrotron, Spain), respectively.

The CLEAR X-ray emission spectrometer available at the CLAESS beamline of ALBA synchrotron.

The CLEAR X-ray emission spectrometer installed at the CLAESS beamline of the ALBA synchrotron is described. It is an energy-dispersive spectrometer based on Rowland circle geometry with 1 m-diameter circle. The energy dispersion is achieved by the combination of a diced analyzer crystal and a unidimensional detector. A single unconventional dynamically bent analyzer crystal (Si 111) permits a wide energy range to be covered, just by exploiting its different reflections (333, 444, 555, 777, 888): 6-22 keV, with a spectrometer efficiency that decreases above 11 keV because of the Si detector thickness (Mythen, 350 µm), while the relative scattering intensities for the Si 333, 444, 555, 777 and 888 reflections correspond to 36, 40, 21, 13 and 15, respectively. The provided energy resolution is typically below 1-2 eV and depends on the beam size, working Bragg angle and reflection exploited. In most cases the energy dispersion ranges from 10 to 20 eV and can be enlarged by working in the out-of-Rowland geometry up to 40 eV. The spectrometer works in full backscattering geometry with the beam passing through the two halves of the analyzer. The vacuum beam path and the particular geometry allow a typical average noise of only 0.5 counts per second per pixel. The spectrometer is mainly used for measuring emission lines and high-resolution absorption spectra, with a typical scanning time for highly concentrated systems of around half an hour, including several repeats. The intrinsic energy dispersion allows systematic collection of resonant X-ray emission maps by measuring high-resolution absorption spectra. Moreover, it allows spectra to be measured on a single-shot basis. Resonant inelastic X-ray scattering experiments to probe electronic excitations are feasible, although the spectrometer is not optimized for this purpose due to the limited energy resolution and scattering geometry provided. In that case, to minimize the quasi-elastic line, the spectrometer is able to rotate along the beam path. Advantages and disadvantages with respect to other existing spectrometers are highlighted.

Operando NAP-XPS Studies of a Ceria-Supported Pd Catalyst for CO Oxidation

Supported Pd/CeO2 catalytic systems have been widely investigated in the low-temperature oxidation of CO (LTO CO) due to the unique oxygen storage capacity and redox properties of the ceria support, which highly influence the structural, chemical and electronic state of Pd species. Herein, operando near-ambient pressure XPS (NAP-XPS) technique has allowed the study of a conventional Pd/CeO2 catalyst surface during the CO oxidation reaction under experimental conditions closer to the actual catalytic reaction, unfeasible with other surface science techniques that demand UHV conditions. SEM, HRTEM and XRD analyses of the powder catalyst, prepared by conventional incipient wetness impregnation, reveal uniformly CeO2-loaded Pd NPs of less than 2 nm size, which generated an increase in oxygen vacancies with concomitant ceria reduction, as indicated by H2-TPR and Raman measurements. Adsorbed peroxide (O22−) species on the catalyst surface could also be detected by Raman spectra. Operando NAP-XPS results obtained at the ALBA Synchrotron Light Source revealed two kinds of Pd species under reaction conditions, namely PdOx and PdII ions in a PdxCe1−xO2−δ solution, the latter one appearing to be crucial for the CO oxidation. By means of a non-destructive depth profile analysis using variable synchrotron excitation energies, the location and the role of these palladium species in the CO oxidation reaction could be clarified: PdOx was found to prevail on the upper surface layers of the metallic Pd supported NPs under CO, while under reaction mixture it was rapidly depleted from the surface, leaving a greater amount in the subsurface layers (7% vs. 12%, respectively). On the contrary, the PdxCe1−xO2−δ phase, which was created at the Pd–CeO2 interface in contact with the gas environment, appeared to be predominant on the surface of the catalyst. Its presence was crucial for CO oxidation evolution, acting as a route through which active oxygen species could be transferred from ceria to Pd species for CO oxidation.

Strategies to minimize beam and sample vibration-induced instabilities at the microfocus MX XAIRA beamline at ALBA

The performance of microfocus beamlines, and ultimately the quality of the diffraction data, is very sensitive to vibrations affecting the optical elements and the sample stages and holder. We report here the strategies applied in the design of the microfocus MX XAIRA beamline at ALBA synchrotron to mitigate the effects of two relevant sources of vibrations: circulation of LN2 flow to evacuate the thermal load on the monochromator and cryocooling gas stream being blown on the sample. The internal shape and size of the two cooling pads that clamp the monochromator optics have been designed to minimize the turbulences in the liquid nitrogen flow while maximizing heat transfer. Computational Fluid Dynamics (CFD) simulations and some preliminary metrology tests are presented. Besides, in the end-station, the cryo-cooler is blowing typically a 5-10 L/min flow of nitrogen or helium gas at 100K on the sample, inducing vibrations in the micron range. The optimal geometrical configuration between the sample holder and the cryocooler has been assessed by means of CDF simulations and metrology tests.

A tensile stage for high resolution synchrotron-based infrared microspectroscopy at MIRAS

For the study of thin films and fibres under load, a uniaxial tensile stage has been developed for synchrotron-based polarized Fourier-transform infrared (FTIR) microspectroscopy. One of the advantages compared to commercial available stages is its compact design at the sample position (<20 mm thickness) and the large field of view on the sample for transmission and reflection geometry. In addition, the stage is mounted on a base plate, which can be rotated between -15° and +193° in the sample plane, in order to rotate the sample relative to the inherent polarization of the incoming infrared light from the synchrotron light source. Preliminary in situ tensile load experiments conducted at MIRAS beamline of the ALBA synchrotron were done on 3D printed thermoplastic polyurethane (TPU) polymer thin films. The samples could be mapped in transmission geometry under tensile load achieving high spatial resolution up to 10 micros using the intense IR source of the synchrotron light. Making use of polarized synchrotron-based infrared light, it was possible to show the alignment of different vibrational bands parallel and orthogonal to the stretching direction. The v(C=O) absorbance bands decrease upon stretching using parallel polarized infrared light, while the v(C=C) bands are increasing in intensity, revealing the orientation of v(C=O) bonds orthogonal to the stretching direction during stretching. The experiments highlight the unique instrumentation capabilities of the tensile stage for in situ measurement of molecular distributions and chemical bond orientations as a function of sample displacement and applied load.