Particle‐InducedX‐Ray Emission

Abstract

Particle‐Induced X‐Ray Emission (PIXE) is an analytical technique established in the decade of 1970s, which makes use of MeV ion beams (mainly proton beams) to induce x‐ray emission from materials. It is used both in macro mode, where beam spots are of the order of millimeters, and in micro mode, where ion beams are focused to micrometer size (or even below this, since 100 nm spots are already available for PIXE). It has major advantages for the analysis of sensitive and/or complex samples because it is essentially a non‐destructive technique. For example, some laboratories are equipped with facilities where the beam is extracted into the atmosphere, allowing the analysis of paintings and other cultural heritage samples. Recent developments also make possible the analysis of samples that are not homogeneous but composed of different layers. In this case, PIXE has large advantages relative to electron microprobe analysis (EPMA) because the particle beam scattering is very small, such that the micro‐beam remains focused along several micrometers into the sample. Finally, the use of x‐ray detection systems having high resolution (resolving power of the order of 100 or more) is presently moving from pure fundamental work towards applications as more complex samples need to be analyzed.