Excitonic processes and their contribution to nonproportionality observed in the light yield of inorganic scintillators

Abstract

Using the derived expression for the light yield in a scintillator, the influence of linear radiative and non-radiative (quenching) rates on the nonproportionality in light yield is studied. It is found that if the excitation created within the electron track initiated by a γ-photon incident on a scintillator remains mainly excitonic, then nonproportionality can be minimised by inventing a scintillator material with linear radiative rate >10⁷ s⁻¹, linear quenching rate <10⁶ s⁻¹ and track radius ≥70 nm along with maintaining the rates of other nonlinear processes as discovered earlier. If one can increase the linear radiative rate to 10⁹ s⁻¹, then the nonproportionality can be eliminated at a track radius >20 nm.