The measured electron response nonproportionalities of CaF2, BGO, and LSO

To study the light yield nonproportionality and intrinsic energy resolution of inorganic scintillators, a Compton coincidence technique was previously designed, implemented and benchmarked. This technique provides the ability to accurately measure the electron response of scintillation materials and thus provides an accurate means of studying these characteristics. In this study, the electron responses of two ''classic'' scintillators (CaF2(Eu) and Bi4Ge3O12 (EGO)) and a newer scintillator (Lu2SiO5:Ce3+ (LSO)) have been measured over the energy range from 5 keV to approximately 450 keV using this technique. Electron responses for all three scintillation materials are observed to increase monotonically with electron energy. EGO is observed to have the least nonproportionality, with its electron response varying about 20% over this energy range. Conversely the LSO electron response is observed to vary about 50% over this energy range and thus exhibits the largest nonproportionality.