  The trap depth distribution in persistent phosphors, along with the charging
and working conditions, determines the performance of these phosphors.
Extracting the trap depth distribution is often hindered by the presence of a
thermal barrier for charging, which leads to temperature-dependent filling of
traps. Within the framework of a local charge transition for the trapping and
recombination, we propose a method for extracting the trap depth distribution
from electron population functions. They were converted from thermoluminescence
curves via the Tikhonov regularization in the framework of first-order
kinetics. The theoretical model predicts the evolution of a filling function
for the traps with increasing charging temperature. The relative filling
functions at different charging temperature, together with the corresponding
electron population function, were used to reconstruct the actual underlying
trap depth distribution. The method provides good precision and resolution.
Trap depth distributions deepen our understanding of the properties of
persistent phosphors.
