HIGH RESOLUTION SOFT X-RAY SPECTROMETER FOR CHEMICAL STATE ANALYSIS BY PIXE

A soft X-ray crystal spectrometer designed for chemical state analysis by PIXE is described. A windowless, microchannel plate (MCP) electron multiplier combined with a photodiode array was used as a position-sensitive detector for X-rays diffracted by a plane crystal. The spectrometer was tested for Al Kα and Fe L X-ray spectra induced by 15 MeV N²⁺ ion impact. An energy resolution (FWHM) of 1.5 eV for the 1487 eV Al Kα_{1, 2} line was obtained for metallic Al, and satellite structures of Al Kα arising from multiply ionized states were well resolved. Fe L X-ray spectra were measured for Fe₂O₃ and metallic Fe. Chemical effects were clearly recognized in the Fe Lα/Lβ intensity ratio and in the intensity distributions of their multiple vacancy satellites.