2021 Volume 52 Pages 63-68
F K-edge X-ray absorption spectra (XAS) of insulators such as AlF3 a nd L iF w ere obtained at BL-11 in the SR Center of Ritsumeikan University. To obtain the spectra, two kinds of electron yield methods were used simultaneously. One is total electron yield (TEY) method measuring sample current, and the other is partial electron yield (PEY) method detecting high energy electrons emitted from the sample. As is expected, the TEY method produced distorted spectra for the insulators. The electron emission from the sample surface after the X-ray absorption causes positive potential (charge-up) on the surface. Since the charge-up potential varies during the XAS measurements depending upon the variation in X-ray absorbance and the rate of discharge, the variation in absorbance results in the TEY data distortion. However, it was found that such distortion almost disappeared in the PEY spectra. The PEY method collects only the high energy electrons, thus the number of electrons detected by the PEY detector depends less on the charge-up potential and it can be a very convenient experimental mode for insulator samples.
