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Title: XAFS Measurement System for Nano, Bio and Catalytic Materials in Soft X-ray Energy Region

Abstract

In soft X-ray energy region, there are really many absorption edges for the constituents of the useful materials. We have reported the powerful XAFS measurement system at soft X-ray energy beamline on small or compact storage ring HiSOR and also recent NEXAFS spectra data about nano, bio and catalytic materials. The XAFS measurement system has a Be window, which can separate the ultra-high vacuum (UHV) and the atmospheric pressure condition. Moreover the XAFS spectra can obtain by yielding a fluorescent X-ray emitted from the samples.

Authors:
; ; ; ;  [1];  [2];  [3]; ; ;  [4]
  1. School of Engineering, Nagoya University, Furo-cho, Chikusa-ku, Nagoya, 464-8603 (Japan)
  2. School of Dentistry, Tokyo Medical and Dental University, Yushima, Bunkyo-ku, Tokyo, 113-8549 (Japan)
  3. Department of Physiology, Tsurumi University, 2-1-3 Tsurumi, Tsurumi-ku, Yokohama, 230-8501 (Japan)
  4. Synchrotron Radiation Center, Hiroshima University, Kagamiyama, Higashi-Hiroshima, 739-8526 (Japan)
Publication Date:
OSTI Identifier:
21049329
Resource Type:
Journal Article
Resource Relation:
Journal Name: AIP Conference Proceedings; Journal Volume: 879; Journal Issue: 1; Conference: 9. international conference on synchrotron radiation instrumentation, Daegu (Korea, Republic of), 28 May - 2 Jun 2006; Other Information: DOI: 10.1063/1.2436381; (c) 2007 American Institute of Physics; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
43 PARTICLE ACCELERATORS; ABSORPTION; ABSORPTION SPECTROSCOPY; ATMOSPHERIC PRESSURE; BIOLOGICAL MATERIALS; CATALYSTS; EMISSION; FINE STRUCTURE; NANOSTRUCTURES; SOFT X RADIATION; STORAGE RINGS; X-RAY SPECTRA; X-RAY SPECTROSCOPY

Citation Formats

Yagi, Shinya, Nomoto, Toyokazu, Ashida, Takaki, Miura, Kazuya, Soda, Kazuo, Yamagishi, Kazue, Hosoya, Noriyasu, Kutluk, Ghalif, Namatame, Hirofumi, and Taniguchi, Masaki. XAFS Measurement System for Nano, Bio and Catalytic Materials in Soft X-ray Energy Region. United States: N. p., 2007. Web. doi:10.1063/1.2436381.
Yagi, Shinya, Nomoto, Toyokazu, Ashida, Takaki, Miura, Kazuya, Soda, Kazuo, Yamagishi, Kazue, Hosoya, Noriyasu, Kutluk, Ghalif, Namatame, Hirofumi, & Taniguchi, Masaki. XAFS Measurement System for Nano, Bio and Catalytic Materials in Soft X-ray Energy Region. United States. doi:10.1063/1.2436381.
Yagi, Shinya, Nomoto, Toyokazu, Ashida, Takaki, Miura, Kazuya, Soda, Kazuo, Yamagishi, Kazue, Hosoya, Noriyasu, Kutluk, Ghalif, Namatame, Hirofumi, and Taniguchi, Masaki. Fri . "XAFS Measurement System for Nano, Bio and Catalytic Materials in Soft X-ray Energy Region". United States. doi:10.1063/1.2436381.
@article{osti_21049329,
title = {XAFS Measurement System for Nano, Bio and Catalytic Materials in Soft X-ray Energy Region},
author = {Yagi, Shinya and Nomoto, Toyokazu and Ashida, Takaki and Miura, Kazuya and Soda, Kazuo and Yamagishi, Kazue and Hosoya, Noriyasu and Kutluk, Ghalif and Namatame, Hirofumi and Taniguchi, Masaki},
abstractNote = {In soft X-ray energy region, there are really many absorption edges for the constituents of the useful materials. We have reported the powerful XAFS measurement system at soft X-ray energy beamline on small or compact storage ring HiSOR and also recent NEXAFS spectra data about nano, bio and catalytic materials. The XAFS measurement system has a Be window, which can separate the ultra-high vacuum (UHV) and the atmospheric pressure condition. Moreover the XAFS spectra can obtain by yielding a fluorescent X-ray emitted from the samples.},
doi = {10.1063/1.2436381},
journal = {AIP Conference Proceedings},
number = 1,
volume = 879,
place = {United States},
year = {Fri Jan 19 00:00:00 EST 2007},
month = {Fri Jan 19 00:00:00 EST 2007}
}
  • X-ray absorption fine structure (XAFS) measurements are widely used for the analysis of electronic structure. Generally, XAFS in the soft X-ray region is measured under vacuum, but chemical structures under vacuum are typically different from those under operando conditions, where chemical species exhibit their function. Here, we developed an XAFS measurement instrument, as a step toward operando fluorescent, which yields XAFS measurement using synchrotron radiation in the soft X-ray region. We applied this method to analyze the local electronic structure of the sulfur atoms in L-cysteine in different pH solutions. In water at pH 7, the hydrogen atom does notmore » dissociate from the thiol (-SH) group in L-cysteine, which forms a structure surrounded by and interacting with water molecules. The XAFS spectrum of L-cysteine in solution was altered by changing the pH. At pH 9, the hydrogen atom dissociated and a thiolate anion was formed. Although the -SH group was oxidized to SO{sub 4}{sup 2−} when L-cysteine was adsorbed on a metal surface and dried, no oxidation was observed in solution. This may be because the water molecules were densely packed and protected the -SH group from oxidation. Our results show that this instrument aimed toward operando fluorescence XAFS measurements in the soft X-ray region is useful for structural analysis of sulfur atoms in organic molecules in air and in solution. The instrument will be applied to the structural analysis of materials containing elements that have absorption edges in soft X-ray region, such as phosphorus and alkali metals (potassium and cesium). It will be also particularly useful for the analysis of samples that are difficult to handle under vacuum and materials that have specific functions in solution.« less
  • A soft X-ray spectroscopy system has been constructed at the Synchrotron Radiation Center at Ritsumeikan University in which XAFS spectra in different modes, total electron yield, fluorescence yield and transmission, can be obtained simultaneously. It not only shortens total measurement time but also allows to make direct comparison of the spectra from the same sample area containing somewhat different information on the atomic and electronic structure of sample material. Spectra of silicon dioxide deposited on the silicon substrate and those of sodium thiosulfate are shown as examples. Discussion is given on the possibility of the use of the system formore » investigating absorption mechanism in sample material.« less
  • We have developed a compact experimental set-up for X-ray absorption fine structure (XAFS) measurements in He at atmospheric pressure (AP) in the soft X-ray region and used it for Mg and Cl K-edge XAFS measurements of MgCl{sub 2} and MgCl{sub 2{center_dot}}6H{sub 2}O. The spectra of MgCl{sub 2{center_dot}}6H{sub 2}O measured in He at AP were significantly different from those measured in vacuum. This suggests the importance of performing soft X-ray XAFS experiments under AP to obtain reliable spectra from hydrated compounds.
  • We have proposed a new experimental arrangement to measure spectral reflectance of nano-materials for analyzing higher order structure with laser-plasma soft x-rays. Structure modification of annealed Mo/Si multilayers and a nylon-6/clay hybrid with poor periodicity was investigated. The measurement of the spectral reflectance of soft x-rays from laser-produced plasma was found to be a useful method for the structure analysis of nano-materials, especially those of rather poor periodicity.
  • A detector setup with three LN-cooled Si(Li) diodes is used to measure soft x-ray spectra (0.8--20 keV) emitted from the inside walls of the PDX vessel during the plasma discharge. The setup is part of a pulse-height-analysis system, which is used to measure the plasma and wall radiation simultaneously at five different radial positions. The wall and the plasma radiation are measured under different plasma conditions (e.g., OH and neutral beam heating). The wall radiation is very much increased during the neutral beam heating, with an enhancement factor of at least 10 over the OH wall radiation. Since we measuremore » the plasma and the wall radiation at the same time, the measurements allow the conclusion that the wall radiation can be attributed essentially to fluorescence (line radiation, e.g., Ti-K/sub ..cap alpha../) and scattering (continuum part of the wall radiation spectrum). The fluorescence and the scattering are both caused by soft x-ray radiation flux coming from the plasma. There seems to be no need to invoke other, more exotic causes for the wall radiation, for example, charge particle bombardment of the wall.« less