X‐ray fluorescence measurements of x‐ray absorption near edge structure at the Si, P, and S L edges

High‐resolution (≤0.2 eV) x‐ray absorption near edge structure (XANES) spectra have been recorded at the Si, P, and S 2p edges of several compounds using microchannel plates to detect the ultrasoft x‐ray fluorescence after 2p excitation or ionization. The fluorescence yield (FY) XANES of SiO₂, Si, InP, FeS₂, and Na₂S₂O₃ are of at least as good quality as the XANES recorded using total electron yield (TEY), despite the extremely small fluorescence yield. The FY spectra obtained show two significant advantages over the TEY spectra. First, the FY XANES is much more bulk sensitive; and second the resolution of the FY spectra is usually considerably better.