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High-focusing Bragg-Crystal polychromator design for energy-dispersive X-ray absorption spectroscopy
J Pellicer-Porres1, A San Miguel, A Fontaine
1European Synchrotron Radiation Facility, BP 220, F-38043 Grenoble CEDEX, France.
Journal of Synchrotron Radiation
|May 12, 2006
Summary
A new silicon Bragg crystal polychromator design offers highly focused X-ray beams for extended X-ray absorption fine structure (EXAFS) experiments. This advancement achieves the smallest spot sizes for EXAFS optics, enhancing experimental capabilities.
Area of Science:
- Materials Science
- Condensed Matter Physics
- Synchrotron Radiation Science
Background:
- Dispersive extended X-ray absorption fine structure (EXAFS) experiments require precise focusing optics.
- Existing optics may not fully leverage advanced synchrotron light sources.
Purpose of the Study:
- To design and optimize a highly focusing profiled Silicon(111) Bragg crystal polychromator.
- To achieve optimal focusing for dispersive EXAFS experiments across a broad energy range (4-13 keV).
Main Methods:
- Utilized X-ray tracing simulations to optimize crystal profile and geometry.
- Considered all degrees of freedom in the optical design.
- Leveraged capabilities of undulator sources and beamline optics (ID24 at ESRF).
Main Results:
- Developed a profiled Si(111) Bragg crystal polychromator with optimized focusing.
- Achieved measured spot sizes between 20 and 40 micrometers in the 5-12 keV range.
- Obtained the smallest spot sizes reported for energy-dispersive EXAFS optics while maintaining a wide energy bandpass.
Conclusions:
- The designed polychromator provides superior focusing for EXAFS experiments.
- The results validate the optimization approach using X-ray tracing simulations.
- This advancement enables enhanced X-ray absorption spectroscopy experiments at synchrotron facilities.
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