Particle-induced gamma emission
Particle-induced gamma-ray emission (PIGE) spectroscopy is a form of nuclear reaction analysis, one of the ion beam analysis thin-film analytical techniques. == Technology == Typically, an MeV proton beam is directed onto a sample which may be tens of microns thick, and the fast protons may excite the target nuclei such that gamma rays are emitted.
Source: Wikipedia — Particle-induced gamma emission (CC BY-SA 4.0)