Fundamental limitations of scintillators

Speed and light output are the two most important parameters characterizing scintillation materials. While the limit of speed is set by the Einstein coefficientA of the relevant luminescent transition, light output is determined by efficiencies of three processes acting in sequence: energy conversion, transfer and luminescence. We will present a scheme to characterize any given material and apply it to some known and established materials as well as to new materials utilizing d-f transitions on Ce3+ ions. We will demonstrate that, while the conversion efficiency may, in some cases, be low because of high losses to optical phonons, it is by far the transfer step, which is responsible for vast differences in light outputs of different Ce materials.