Polycapillary-optics-based micro-XANES and micro-EXAFS at a third-generation bending-magnet beamline

Geert Silversmit, Bart Vekemans, Sergey Nikitenko, Wim Bras, Viktoria Czhech, Gyula Zaray, Imre Szaloki, Laszlo Vincze

Research output: Contribution to journalArticle

22 Citations (Scopus)

Abstract

A focusing system based on a polycapillary half-lens optic has been successfully tested for transmission and fluorescence -X-ray absorption spectroscopy at a third-generation bending-magnet beamline equipped with a non-fixed-exit Si(111) monochromator. The vertical positional variations of the X-ray beam owing to the use of a non-fixed-exit monochromator were shown to pose only a limited problem by using the polycapillary optic. The expected height variation for an EXAFS scan around the Fe K-edge is approximately 200 m on the lens input side and this was reduced to 1 m for the focused beam. Beam sizes (FWHM) of 12-16 m, transmission efficiencies of 25-45% and intensity gain factors, compared with the non-focused beam, of about 2000 were obtained in the 7-14 keV energy range for an incoming beam of 0.5 2 mm (vertical horizontal). As a practical application, an As K-edge -XANES study of cucumber root and hypocotyl was performed to determine the As oxidation state in the different plant parts and to identify a possible metabolic conversion by the plant.

Original languageEnglish
Pages (from-to)237-246
Number of pages10
JournalJournal of Synchrotron Radiation
Volume16
Issue number2
DOIs
Publication statusPublished - Mar 9 2009

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Keywords

  • Bending-magnet station
  • Non-fixed-exit onochromator
  • Polycapillary half-lens optic
  • μ-EXAFS
  • μ-XANES
  • μ-XAS

ASJC Scopus subject areas

  • Radiation
  • Nuclear and High Energy Physics
  • Instrumentation

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