BL2.2: Time-resolved X-ray Absorption Spectroscopy (TRXAS)

An energy dispersive x-ray absorption spectroscopy beamline has been constructed at the Synchrotron Light Research Institute (SLRI), Thailand. The beamline was designed to utilize the synchrotron radiation with photon energies between 4000 and 12000 eV. The horizontal focusing of the bent crystal in the energy dispersive monochromator offers a small polychromatic focal spot of 1 mm at the sample position. By employing an energy dispersive scheme, the whole x-ray absorption near edge structure (XANES) can be obtained simultaneously using a position sensitive detector with the fastest readout speed of 25 ms. The short data collection time opens a new opportunity for time-resolved x-ray absorption spectroscopy (XAS) experiments such as studies of changes of the electronic structures or the local coordination environments of an atom during a change in thermodynamic conditions.

The time-resolved XAS (TRXAS) beamline is designed to utilize synchrotron radiation generated from a bending magnet of a 1.2 GeV storage ring of the Siam Photon Source. It employs the energy dispersive monochromator (EDM) and a 2-theta arm with an angular range from 20 to 140 degrees which were donated by the University of Bonn, Germany. The components belonged to a decommissioned beamline at the Electron Stretcher and Accelerator (ELSA) of the University of Bonn. With a Si(111) crystal, the EDM covers photon energies between 4000-12000 eV, allowing the K-edges of Ca to Ga to be investigated at this beamline. The rest of the beamline components was designed and fabricated in-house.

Fig1 editted 20120929 jpg

Figure 1. Optical layout of EDXAS scheme. X-rays with a certain energy bandwidth are selected by a bent crystal. The position sensitive detector (PSD) is placed downstream of the sample to detected all the transmitted x-rays simultaneously thus allowing the measurement of XAS spectrum in a short period of time

Figure 2 Schematic of the TRXAS beamline showing the main components, namely the heat absorber (ABS), front-end mask, differential-pressure tube, beam shutter (BS), retractable water-cooled Be foil, beam-position mornitor (BPM), two sets of vertical and horizontal slits and EDM. Distances from the source (in mm) are also shown.

Figure 3 Normalized Ti K-edge XANES spectra for a 5 micrometer thick Ti foil measured using integration time of 25, 50, 100, 200, 500, 800 and 1000 ms.

Technical specification

Electron energy: 1.2 eV
Operational photon energy : 4-12 keV
Crystal: Si (111, 220) 250 x 25 x 1 mm3
Source-to-crystal distance: 9.7 m
Detector: NMOS linear image sensor (1024 pixels, Hamamatzu)
Optical bench: 2.8 m long

Applications

Temperature Programmed Oxidation/Reduction

Temperature range: 30-7000C,

Available Gases : Hydorgen, Oxygen, Nitrogen, Helium, Argon, Flammable gas (optional)

Journal of Synchrotron Radiation 19 (2012), P. 937-943

Temperature programmed reduction (H2-TPR)

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Materials Science and Engineering B 190 (2014) 82–89

Charging/discharging of battery

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Int. J. Electrochem. Sci., 9 (2014) 4257 - 4267

Reference

Y. Poo-arporn, P. Chirawatkul, W. Saengsui, S. Chotiwan, S. Kityakarn, S. Klinkhieo, J. Hormes and P. Songsiriritthigul, Time-resolved XAS (Bonn-SUT-SLRI) beamline at SLRI, Journal of Synchrotron Radiation 19 (2012), P. 937-943

W. Limphirat, N. Wiriya, S. Tonlublao, S. Chaichoy, P. Pruekthaisong, S. Duandmanee, P. Kamonpha, D. Kaewsuwan, N. Meethong, R. P. Poo-arporn, P. Songsiriritthigul, J. Hormes, Y. Poo-arporn, The current status of time-resolved XAS beamline at SLRI and application on in situ experiments, Radiation Physics and Chemistry 171 (2020), 108750.

Contact Tel. +66 44 217040
Dr. Yingyot Poo-arporn (beamline manager)	ext. 1478	This email address is being protected from spambots. You need JavaScript enabled to view it.
Dr. Wanwisa Limphirat (beamline scientist)	ext. 1471	This email address is being protected from spambots. You need JavaScript enabled to view it.
Beamline	ext. 1657

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