Fig. 1. Schematic diagram of the Darwin differential method

Fig. 2. Multi-Lamellar approximate dynamic diffraction calculation model^[35]. (a) Bragg crystal; (b) Laue crystal

Fig. 3. Correction results of rocking curves of different crystals by multilayer approximate model^[37]. (a) 228.6 mm; (b) 152.4 mm; (c) 101.6 mm; (d) 50.8 mm

Fig. 4. Dynamic diffraction of Si(004) crystal with a 12-keV planewave^[47]. (a) Simulated optical path model; (b) diffracted wave; (c) transmitted wave; (d) energy flow; (e) diffracted intensity; (f) diffracted wave in 0° deviation angle; (g) transmitted wave in 0° deviation angle; (h) energy flow in 0°deviation angle

Fig. 5. Structure of typical bending focusing X-ray crystal spectrometer. (a) Johann spectrometer; (b) Johansson spectrometer

Fig. 6. Optical path of spherical curved crystal. (a) Diffraction light path along meridional/sagittal plane; (b) focus distance of meridional/sagittal plane

Fig. 7. Johann spectrometer with spherical bent crystal^[68]. (a) Schematic of spectrometer; (b) K-edge spectra and reference spectrum of selenium accumulation in pseudomonas

Fig. 8. Vacuum-formed bent crystal analyzer^[70]. (a) Experimental setup; (b) focus imaging contrast of SBCA & VF-BCA

Fig. 9. Focusing principle of toroidal crystal. (a) Diffractive light path along meridional/sagittal plane; (b) focus distance of meridional/sagittal plane

Fig. 10. Toroidal spectrometer^[76]. (a) Illustration of spectrometer; (b) grid imaging distribution; (c) comparison between toroidal crystal and spherical curved crystal; (d) imaging resolution

Fig. 11. Four-channel toroidal curved crystal spectrometer^[77]

Fig. 12. Different von Hamos curved crystal spectrometers^[78]. (a) Standard von Hamos focusing structure; (b) von Hamos focusing structure in XES spectrometer; (c) von Hamos focusing structure in XAFS spectrometer

Fig. 13. Comparison between von Hamos LiNbO₃(014-) crystal spectrometer and Johansson Si(111) crystal spectrometer^[81]. (a) Schematic of spectrometer; (b) comparison of the sulfur K_α XES

Fig. 14. Integrated von Hamos multi-crystal spectrometer^[82]. (a) Spectrometer with sixteen Si(111) crystals; (b) spectra of elastic scattering measurement

Fig. 15. Segmented von Hamos spectrometer and the spectrum specifications^[83]. (a) Diagram of principle; (b) diagram of setup; (c) measured Bragg angle; (d) measured resolution

Fig. 16. X-ray dispersion on the meridional plane of conical crystal

Fig. 17. Segmented conical analyzer^[90]. (a) Schematic of structure; (b) measured Mn K_α lines

Fig. 18. Diffraction focusing structure of conical crystal spectrometer with continuous variable curvature^[94]

Fig. 19. Variable curvature surface crystals prepared by thermoplastic method^[92]. (a) Schematic of fabrication process; (b) Ge crystal with variable curvature surface; (c) acquired XRF data

Fig. 20. Schematic of the multi-cone crystal and its performance^[96]. (a) Multi-cone α-quartz crystal; (b) spectrum comparison between multi-cone crystal and plane crystal; (c) focusing performance comparison between multi-cone crystal and plane crystal