Fig. 1. Transmission of X-ray for C1 windows with different energies

Fig. 2. Experimental setup of fluorescence-detected soft X-ray absorption measurement

Fig. 3. Absorption spectrum data acquisition flow chart and software interface based on LabView. (a) Flow chart of data acquisition; (b) user interface

Fig. 4. Fluorescence spectra at photo energy of 700 eV

Fig. 5. 2D-mapping of fluorescence intensity with incident photon energy varied from 680 eV to 714 eV

Fig. 6. F K-edge absorption spectra of target gas CF₄ obtained through partial fluorescence yield

Fig. 7. F K-edge absorption spectrum of target gas CF₄ obtained through partial fluorescence yield when the pressure is 6.7 Pa

Fig. 8. Fluorescence absorption spectrum for N element in iodine methylamine lead (CH₃NH₃PbI₃)