3. Comparison with other excitation modes

X-ray emission can be induced by various exciting probes: heavy charged particles such as protons or alpha particles (PIXE), electrons (EPMA, EDX), X-ray photons and gamma photons from radioactive sources. Each of the resulting analytical techniques has its own specific advantages, such as analytical sensitivity, wide accessibility to a broad scientific community, or the fact that it can be applied on a microscopic scale. On this last point, techniques based on the use of gamma photons or X-ray photons from conventional X-ray tubes (XRF) cannot compete with synchrotron radiation sources (SXRF) with much brighter beams.