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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 2400 and 8000 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 2400-12000 eV, allowing the K-edges of S to Co to be investigated at this beamline. The rest of the beamline components was designed and fabricated in-house.

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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  

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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 : 2.4-12 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

Thermal oxidation

      

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

 

Temperature program reduction

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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

Contact Tel. +66 44 217040

Dr. Yingyot Poo-arporn (beamline scientist)

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

Menu : BL2.2: TRXAS

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Synchrotron Light Research Institute,slri2

111 University Avenue, Muang District, Nakhon Ratchasima 30000, THAILAND
Postal address : P.O. Box 93, Muang, Nakhon Ratchasima 30000, THAILAND

Tel.: 66 44 217 040 Fax: 66 44 217 047 Email: siampl@slri.or.th

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