ABSTRACT
The general objective of spectroscopy is to obtain, at a minimum, the qualitative identification of the source. Gamma rays and x rays are photons of electromagnetic radiation that are capable of producing ionization through the interactions with ambient atoms. The liberated photoelectron moves through the detector medium causing more ionization through Coulombic interactions. At higher photon energies, ranging between tens of keV up to several MeV, depending on the material, the Compton scattering effect becomes dominant compared to the photoelectric effect. In practice, for geometrical reasons, it is unlikely that forward scattering in the surroundings or shielding results in a significant number of scattered photons entering the detector. The shielding and surrounding material, when irradiated by energetic photons, can also fluoresce by the emission of characteristic x rays. Although much of bremsstrahlung is self-absorbed in the shielding, some of it can still interact in the detector. Measurements requiring high resolution spectroscopy generally require more expensive semiconductor spectrometers.
