Upgrades to the XAFS2 beamline control system and to the endstation at the LNLS

Abstract

Abstract. The XAFS2 is a general-purpose X-ray absorption beamline. It is the second one built at the LNLS. After approximately 7 years in operation this beamline has been substantially updated in order to improve its experimental possibilities. Recently arrived, a 4-circle Huber diffractometer has been incorporated to perform combined experiments. This collects XRD patterns with the XAFS. Through the development of a new sampling environment it is now also possible to perform these measurements in situ/operando conditions. Other upgrades include a complete remodelling of the beamline software and its control system. The following new systems are crucial for the next steps that are currently underway at the beamline, namely, (i) enabling remote access for users and (ii) the testing of QEXAFS measurements. IntroductionUpon the completion, in 2007, of the commissioned works on the XAFS2 [1], a large number of users have been using this experimental facility in order to perform several kinds of experiments [2][3][4][5]. Since 2007, and with the development of combined simultaneous characterizations [6], there are a plethora of new possibilities additional to the usual XAFS experiments. Among these numerous possibilities; a combined XAFS and XRD experiment would be especially useful in order to obtain structural information of the short range order (around a selected absorber atom) and of the long range order, thus unveiling information on the material as a whole. Here one is probing different properties of the same system in a unique experiment under the same conditions, thus bridging the complex gaps in the structure. Therefore, in order to improve those abilities of the beamline, a 4-circle Huber Diffractometer was added to the experimental hutch in order to explore both techniques [7] through user demand. Here below an example of these XAFS and XRD measurements is presented. The example shows the performance of the beamline at work while combining both techniques.Importantly, the control system of the beamline has been renovated by the installation of a PXI. The PXI is from National Instruments (PXI-NI) and communicates with Galil/Parker controllers on an EPICS platform [8]. Note some parts of the motors were changed in order to improve performance with the upgrade and there were also important changes to the control hardware. The Windows

Increasing the optical response of TiO2 and extending it into the visible region through surface activation with highly stable Cu5 clusters

“…X-ray Absorption Spectroscopy (XAS) measurements in the XANES (X-ray absorption near edge structure) regions were performed at the XAFS2 beamline72 of the Laboratorio Nacional de Luz Síncrotron (LNLS), Campinas, Brazil. The measurements were performed in transmission mode using a Si(111) crystal monochromator near the Cu K-edge (8979 eV) and Ti K-edge (4966 eV) at ambient temperature with three ion chambers as detectors.…”

X-ray absorption spectroscopy and Eu3+-emission characteristics in GaAs/SnO2 heterostructure

“…Thus, the samples were attached to the equipment to perform the measurement. Absorption spectra were also measured using the XAFS2 beamline of the Brazilian Synchrotron Light Laboratory (LNLS-Campinas, Brazil) [30], and the XANES spectra were collected in fluorescence mode, using a Canberra Ge-15 solid state detector. For XAS analysis, the XANES spectra have been normalized by eliminating the signal of residual absorption (μ 0 ), due to all elements located in the beam path in the sample.…”

The Impact of Ceria Loading on the CuOx−CeO2 Interaction and Performance of AuCu/CeO2−SiO2 Catalysts in CO‐PROX Reaction

“…The activation (reductive pretreatment) was performed from room temperature up to 400 °C under 5 % H 2 /He flow (total flow: 50 mL min −1 ) (Figure S1b), using a homemade furnace working in θ–2θ mode. XAFS (X‐ray absorption fine structure spectroscopy) measurements at Au−L 3 (11919 eV), Cu−K (8979 eV), and Ce−L 3 edges (5723 eV) were carried out at XAFS2 beamline at LNLS, [54] in transmission mode. The samples were analyzed before (just calcined) and after the activation (Figure S1c).…”