Luminescence properties and scintillation mechanisms of Ce3+-, Pr3+- and Nd3+-doped lutetium pyrosilicate

Whereas Ce3+-doped Lu2Si2O7 presents a high scintillation light yield (around 26,000 ph/MeV), Pr3+- and Nd3+-doped Lu2Si2O7 (LPS) are not so efficient (5000 ph/MeV and <1000 ph/MeV, respectively). Time-resolved spectroscopy using synchrotron radiation was used in order to study either undoped LPS and Ce3+-, Pr3+- or Nd3+-doped (LPS). The existence of a self-trapped exciton (STE) and its relative energy position could explain the limited light yield of Pr3+-doped LPS. For Nd3+-doped LPS, an efficient non-radiative relaxation from the lowest 4f25d to a 4f3 level (2G7/2), can occur, resulting in poor scintillation properties.