XANES: X-ray Absorption Near Edge Structure

X-ray Absorption Near Edge Strucure (XANES) is a type of X-ray Absorption Spectroscopy (XAS). It refers to the absorption fine structure close to an absorption edge, about the 10 eV below the absorption edge and 20 eV above the edge. This region usually shows the largest variations in the X-ray absorption coefficient and is often dominated by intense, narrow resonances. This technique provides information on the electronic structure o the unoccupied levels and very few techniques can do this. XANES is also called Near Edge X-Ray Absorption Fine Structure (NEXAFS). Today, the term NEXAFS is typically used for soft X-ray absorption spectra (surface sciences, organics) and XANES for hard X-ray spectra (coordination chemistry, metal atoms). 

microXANES is a subset of XANES, where XANES measurements are carried out on a micron-size spatial scale. To do this a small beam is obtained using focusing optics as opposed to larger beam sizes used during regular XAS.