High-pressure, High-temperature X-ray Absorption Fine Structure Transmission Cell for the Study of Aqueous Ions with Low Absorption-edge Energies
We describe a method to acquire x-ray absorption fine structure (XAFS) spectra of low-Z atoms dissolved in high-pressure liquids and supercritical fluids. The method is applicable to energies at and below the Ca K edge (4038.5.5 eV). The cell design incorporates 25 {micro}m-thick x 700 {micro}m diameter diamond x-ray windows in a Poulter-type seal geometry. X-ray focusing mirrors were used to reduce both the horizontal and vertical beam size to about 200 {micro}m so that the incident beam would pass cleanly through the 300 {micro}m aperture of the cell. Pathlengths in the range from 50 to 1000 {micro}m can be selected with appropriate spacers. The maximum operating conditions of the flow-through cell design are 500 C and 1 kilobar. We show that only a relatively small number of XAFS scans are required to generate high signal-to-noise ratio spectra for a supercritical water solution (400 C) containing 1 m CaCl2 using a bending-magnet beamline (20-BM, PNC-CAT, Advanced Photon Source, Argonne National Laboratory).
- Research Organization:
- Pacific Northwest National Lab., Richland, WA (US)
- Sponsoring Organization:
- US Department of Energy (US)
- DOE Contract Number:
- AC05-76RL01830
- OSTI ID:
- 15011661
- Report Number(s):
- PNNL-SA-41977; KC0302020; TRN: US0501291
- Journal Information:
- Review of Scientific Instruments, Vol. 75, Issue 12; Other Information: PBD: 1 Dec 2004
- Country of Publication:
- United States
- Language:
- English
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