A novel method for investigating optically stimulated luminescence in scintillators.

Optically stimulated luminescence (OSL) is a known property in many scintillators, and investigating the branching ratio of thermalized carriers to this photon-emission mechanism could aid both scintillator development and OSL-based dosimetry. We present a novel method for determining the branching ratio of thermalized carriers to OSL in scintillators while monitoring the energy deposition from 511 keV gamma photons on an event-by-event basis. We demonstrate the method using a cerium-doped lutetium oxyorthosilicate (LYSO:Ce) crystal, and validate that the observed signal indeed originates from OSL photons by estimating the lifetime of the OSL traps, which is consistent with values found in the literature. We report a branching ratio of thermalized carriers to the OSL traps in LYSO:Ce of (1.0±0.2)% upon excitation with 511 keV gamma photons, using a one-trap-one-recombination-center model. • New approach for assessing a dosimetric property in scintillators. • Branching ratio to OSL traps in LYSO:Ce reported for the first time. • OSL yield of LYSO:Ce is found to be 400 ± 80 photons per deposited MeV. [ABSTRACT FROM AUTHOR]