Absorption Coefficients of Fine Structures of X-ray Absorption Spectra at Various Absorber Thickness

By using the North American Philips Diffraction Unit and Wide Range Goniometer modified to a tube spectrometer described by Coster and De Lang, the fine structures of X-ray K absorption spectra of copper in metallic copper, CuCl 2 ·2H 2 O, CuSO 4 ·5H 2 O and cobalt in CoCl 2 ·6H 2 O at various thickness were measured. The structures near the absorption edges are affected by the absorber thickness. The mass absorption coefficients of maximum absorption jumps become large with decreasing absorber thickness, and the small maximum and ninimum near the absorption edges also become indistinct with increasing absorber thickness. The wavelengths of these structures are slightly affected. This is due to the finite resolving power of the spectrometer and the tail of the spectral window as mentioned by Parratt. In the high energy regions from the absorption edges the absorption coefficients are not affected by the absorber thickness.