Absolute x-ray energy calibration over a wide energy range using a diffraction-based iterative method.

Area of Science:

• Materials Science
• Condensed Matter Physics
• Analytical Chemistry

Background:

• Accurate x-ray energy calibration is crucial for energy-sensitive scattering and diffraction experiments.
• Existing methods lack precision over wide energy ranges, especially when transmission monitoring is unavailable or optics are fixed.
• A need exists for robust calibration methods applicable to hard x-ray regions.

Purpose of the Study:

• To develop a precise and fast absolute x-ray energy calibration method.
• To overcome limitations of traditional calibration techniques in specific experimental setups.
• To demonstrate the method's applicability in high-pressure and high-energy x-ray studies.

Main Methods:

• An iterative x-ray diffraction (XRD) based approach was employed.
• The method relies on precise variation of sample-to-detector distance using gauge blocks.
• The iterative algorithm converges to accurate x-ray energy values independent of initial guesses.

Main Results:

• The iterative method achieved convergence within 3.5 eV for 31.122 keV x-rays after three iterations.
• Common diffraction standards (CeO2, Au, Si) showed an energy deviation of 14 eV.
• The method was successfully applied to high-pressure GeO2 glass and pair distribution function measurements at 82.273 keV.

Conclusions:

• The proposed iterative XRD method provides precise and fast absolute x-ray energy calibration over a wide energy range.
• This technique is advantageous as it does not require element-specific absorption edges and is suitable for hard x-rays.
• The method demonstrates broad applicability in advanced x-ray characterization techniques.