Fig. 1. Structural diagram of filter and slit assembly

Fig. 2. Simulation model built by Geant4

Fig. 3. Energy spectra of X-rays entering the detector obtained by simulation (a) Without the filter and the slit; (b) With the filter of 12.3 μm (~3 absorption lengths) thickness, and without slit; (c) With the filter of 12.3 μm thickness and the slit; (d) With only the filter of 24.6 μm (~6 absorption lengths) thickness; (e) With the filter of 24.6 μm thickness and the slit

Fig. 4. Schematic diagram of the internal structure of multi-layer grid ionization chamber

Fig. 5. Principle diagram of multi-layer grid ionization chamber detection (color online)

Fig. 6. Schematic diagram of XAFS data acquisition system of BL11B beamline

Fig. 7. Digitized noise box plot of fluorescence gas detector and Lytle detector (color online)

Fig. 8. Layout of intrinsic response time measurement of multi-grid fluorescent ionization chamber

Fig. 9. Rise time of multi-grid fluorescent ionization chamber under different high voltages

Fig. 10. Relationship between the applied voltage and the output intensity of fluorescence gas detector

Fig. 11. Relationship between output intensity of fluorescence gas detector and incident X-ray intensity

Fig. 12. Original XAFS spectrum of the same sample measured by self-developed fluorescence gas detector and Lytle detector respectively. The insets show k-weighted EXAFS in k space (a) XAFS of Cu sample with 0.1 wt% Cu, (b) XAFS of Co₃O₄ with 1 wt% Co, (c) XAFS of Pt/ZEO with 0.5 wt% Pt, (d) XAFS of Mo-Ru sample with 0.2 wt% Mo