BEATS: BEAmline for synchrotron X-ray microTomography at SESAME.

The ID10 beamline of the SESAME (Synchrotron-light for Experimental Science and Applications in the Middle East) synchrotron light source in Jordan was inaugurated in June 2023 and is now open to scientific users. The beamline, which was designed and installed within the European Horizon 2020 project BEAmline for Tomography at SESAME (BEATS), provides full-field X-ray radiography and microtomography imaging with monochromatic or polychromatic X-rays up to photon energies of 100 keV. The photon source generated by a 2.9 T wavelength shifter with variable gap, and a double-multilayer monochromator system allow versatile application for experiments requiring either an X-ray beam with high intensity and flux, and/or a partially spatial coherent beam for phase-contrast applications. Sample manipulation and X-ray detection systems are designed to allow scanning samples with different size, weight and material, providing image voxel sizes from 13 µm down to 0.33 µm. A state-of-the-art computing infrastructure for data collection, three-dimensional (3D) image reconstruction and data analysis allows the visualization and exploration of results online within a few seconds from the completion of a scan. Insights from 3D X-ray imaging are key to the investigation of specimens from archaeology and cultural heritage, biology and health sciences, materials science and engineering, earth, environmental sciences and more. Microtomography scans and preliminary results obtained at the beamline demonstrate that the new beamline ID10-BEATS expands significantly the range of scientific applications that can be targeted at SESAME.

Emergence of the first XAFS/XRF beamline in the Middle East: providing studies of elements and their atomic/electronic structure in pluridisciplinary research fields.

XAFS/XRF is a general-purpose absorption spectroscopy beamline at the Synchrotron-light for Experimental Science and Applications in the Middle East (SESAME), Jordan. Herein, its optical layout is presented along with its powerful capabilities in collecting absorption and fluorescence spectra within a wide energy range (4.7-30 keV). The beamline is equipped with a conventional fixed-exit double-crystal monochromator that allows the collection of an X-ray absorption spectrum within a few minutes in step-by-step mode. An on-the-fly scanning mode will be implemented shortly where the acquisition time will be reduced to less than a minute per scan. The full automation of the beamline allows performing successive measurements under different conditions. The different experimental setups and special features available to users are reported. Examples of XRF and XAFS measurements are presented, showing the performance of the beamline under different standard conditions.

Operational status of the X-ray powder diffraction beamline at the SESAME synchrotron.

The Materials Science (MS) beamline at SESAME (Synchrotron-light for Experimental Science and Applications in the Middle East), dedicated to the X-ray powder diffraction technique, started its operational phase in December 2020 by hosting its first users. The MS endstation comprises a two-circle diffractometer coupled with a PILATUS 300K area detector, with which direct beam images are collected and compared with the initial ray-tracing simulation results. We present a detailed description of the beamline components and the experimental characterization of the main instrumental parameters relying on the instrumental profile and the angular resolution. A representative example for microstructure investigations of a nanocrystalline material is demonstrated.

The first infrared beamline at the Middle East SESAME synchrotron facility.

SESAME (Synchrotron-light for Experimental Science and Applications in the Middle East) is the only synchrotron light facility in the Middle East and neighboring regions, officially opened in 2017. Among the identification and construction of the first operational beamlines, infrared spectromicroscopy was selected as one of the two beamlines to be opened to the general users' program (the so-called Day-1 beamlines). Being one of the most demanded techniques by various scientific communities in the Middle East, the beamline has been designed and implemented in the framework of a collaboration agreement with the French synchrotron facility, SOLEIL. The design, construction and initial performances of the IR beamline (D02-IR), nowadays operational, are reported.

Unexpected behavior of the surface composition of PtRh alloys during chemical reaction.

The changes in the surface composition of a Pt(50)Rh(50)(100) alloy due to an ongoing 2H(2) + O(2)-->2H(2)O chemical reaction have been studied in situ. Exploiting the high-energy resolution and surface sensitivity of synchrotron radiation core-level spectroscopy it was possible to monitor the population of the two transitions metals atoms at the gas-surface interface. Sequences of fast high-resolution core-level spectra of the Rh3d(5/2), Pt4f(7/2), and O1s core levels showed a continuous exchange of atoms between the first and subsurface layers. An unexpected Pt surface enrichement was found under slightly oxidizing conditions, opposite to what found in a highly oxidizing atmosphere.

Adsorption of CO2 and coadsorption of H and CO2 on potassium-promoted Cu(115).

The influence of potassium, in the submonolayer regime, on the adsorption and coadsorption of CO2 and H on a stepped copper surface, Cu(115), has been studied by photoelectron spectroscopy, temperature-programmed desorption, and work-function measurements. Based on the fast recording of C 1s and O 1s core-level spectra, the uptake of CO2 on K/Cu(115) surfaces at 120 K has been followed in real time, and the different reaction products have been identified. The K 2p3/2 peak exhibits a chemical shift of -0.4 eV with CO2 saturation, the C 1s peaks of the CO3 and the CO species show shifts of -0.8 and -0.5 eV, respectively, and the C 1s peak of the physisorbed CO2 exhibits no shift. The effects of gradually heating the CO2/K/Cu(115) surface include the desorption of physisorbed CO2 at 143 K; the desorption of CO at 193 K; the ordering of the CO3 species, and subsequently the dissociation of the carbonate with desorption at 520-700 K. Formate, HCOO-, was synthesized by the coadsorption of H and CO2 on the K/Cu(115) surface at 125 K. Formate formed exclusively for potassium coverages of less than 0.4 monolayer, whereas both formate and carbonate were formed at higher coverages. The desorption of formate-derived CO2 took place in the temperature range 410-425 K and carbonate-derived CO2 desorbed at 645-660 K, depending on the potassium coverage.