Rocking curve and spatial coherence properties of a long X-ray compound refractive lens

Area of Science:

• Optics and Photonics
• Materials Science

Background:

• Accurate modeling of long X-ray compound refractive lenses (CRLs) is crucial for advanced X-ray applications.
• Previous theories often simplified geometrical aperture, angular divergence, and source size effects in CRL systems.

Purpose of the Study:

• To develop and validate a refined semi-analytical theory for long X-ray CRLs.
• To accurately account for geometrical aperture, angular divergence, and source size.
• To estimate the transverse coherence length of X-ray beams after passing through complex CRL sets.

Main Methods:

• Development of a semi-analytical theory based on recurrence relations.
• Incorporation of precise geometrical aperture, angular divergence, and source size parameters.
• Validation against experimental data for a 40.7 cm Beryllium (Be) CRL.

Main Results:

• The theory accurately predicts the rocking curve width of a long Be CRL, aligning with experimental results.
• The transverse coherence length of an X-ray beam after passing through CRLs of arbitrary complexity is estimated.
• At the focal point, the calculated coherence length matches the diffraction-limited beam size, showing minimal deviation from the real beam size.

Conclusions:

• The developed semi-analytical theory provides a robust framework for analyzing long X-ray CRL systems.
• The accurate estimation of transverse coherence length is vital for optimizing X-ray beam quality and applications.
• The theory's predictive power supports the design and application of advanced X-ray optics.