We demonstrate the potential of X-ray photo-emission electron microscopy (XPEEM) to reveal valence-state images of the spatial distribution and relative concentration of metals in specific oxidation states. Additionally, XPEEM allows X-ray absorption spectra to be extracted from chosen pixel areas of the images. Using an in-house-built XPEEM instrument we show an application of the method in providing valence-state images of complex mineral intergrowths. The image resolution achieved with this instrument of simple design was ∼5 μm and reasonable quality X-ray absorption spectra were extracted from areas of ∼5×5 μm. These initial results suggest that by using commercial XPEEM instruments on 3rd generation, high-brightness synchrotron sources a spatial resolution of 100 nm or better could be achieved, with the ability to extract high-quality X-ray absorption spectra from areas of 0.1 μm2. Given that standard thin sections or polished blocks can be studied by XPEEM, and that each XPEEM image records ∼1000 μm2, XPEEM can be used in conjunction with other analytical methods such as EMPA and TEM-EELS/PEELS.

Microanalysis on the 10-nm level using imaging, diffraction, and spectroscopy of slow photo-emitted and reflected electrons is discussed. The instrumentation that uses a cathode lens is briefly reviewed, and a number of applications illustrate the power of this microanalysis method.