Charles Explorer logo
🇬🇧

Diffraction of X-rays by Perfect Crystals

Class at Faculty of Mathematics and Physics |
NFPL038

Syllabus

1. Introduction. Historical remarks. Anomalous dispersion, atom from-factor, structure factor. Diffraction geometry, symmetrical and asymmetrical case, factor of asymmetry, Bragg and Laue case of X-ray diffraction. Refraction index of X-rays, generalized Ewald construction.

2. Perfect (nearly) infinite single crystal. Electromagnetic elements of dynamic theory of diffraction. Relative permitivity as a periodic function. Wave equation and its solution. Unified wave field. Dispersion equation. Polarization factor. Dispersion surfaces, properties of wave-field components. Multiple-beam cases.

3. Restricted perfect single crystal. Wave field in restricted crystal, graphical solution, determination of wave points. Boundary conditions in thick crystal with negligible absorption, primary extinction. Reflection coefficient, region of total reflection and deviation from Bragg angle for Bragg case. Pendelloesung phenomenon, criterion of applicability of dynamic theory. Energy flow in crystal. Wave field in crystal with absorption, Borrmann phenomenon. Beam of finite size. Restrictions of plane-wave theory, diffraction of spherical waves.

4. Real single crystal. Wave fields, methods of geometric optics, methods of wave optics, introduction to Takagi-Taupin theory.

5. Experimental aspects dynamic theory. High-resolution X-ray diffractometry, multiple-crystal arrangements, structure properties of epitaxial layers. X-ray difraction topography, study of real structure of single crystals.

Annotation

Electromagnetic bases of dynamic theory of X-ray diffraction. Wave field in crystal, absorption, energy flow, anomalous dispersion. High-resolution X-ray diffractometry, X-ray topography. Multiple crystal arrangements. For students of 4th and 5th year - Solid state physics.

Suitable after lectures FPL012 and FPL030