This work investigates the thermoluminescent (TL) glow of Er2O3-doped ZrO2 sample, after separate irradiation with UV and synchrotron x-ray radiations. Experimental results indicate that, in addition to a major TL peak at 98 °C and a minor one at 205 °C, another minor peak appears at 135 °C. The intensity of two minor peaks, particularly the one at 135 °C, increases rapidly with the photon energy. Initial rise method is used to obtain the activation energies of 0.96 and 0.99 eV for 135 and 205 °C TL peaks, respectively. Moreover, the trap depth is theoretically estimated by invoking a HHe+2 like model in which an electron is trapped by an effective positive charge localized on an oxygen site but perturbed by two effective positive charges localized on a cation site. Derived theoretical trap depths, 0.95 and 0.97 eV, are in excellent agreement with experimental values. © 1999 American Institute of Physics.