The constituent elements of the sample absorb some of these neutrons and emit prompt gamma rays which are measured with a gamma ray spectrometer.
Iridium-192 is commonly used as a gamma ray source in industrial radiography to locate flaws in metal components.
Iridium-192 is also a strong gamma ray emitter.
The neutron can be detected by its capture on an appropriate nucleus, releasing a gamma ray.
A secondary gamma ray with less energy (hence lower frequency) also emerges from the interaction.
During this interaction, energy is transferred from the gamma ray to the electron, which is a directly ionizing particle.
The atom is not ionised, and the gamma ray continues on, although at a lower energy.
This low gamma ray production rate makes it more difficult to find and identify this isotope.