Thermoluminescence and Phosphorescence of VUV‐ and X‐Irradiated CaO Monocrystals at Low Temperatures

Thermoluminescence (TL) of CaO and CaO‐Bi monocrystals VUV‐irradiated at 80 K or X‐irradiated at 4.2 K is reported. Varying the energy of VUV‐irradiation, the TL creation spectra (TLCS) of various peaks are derived. From the analysis of these spectra it is concluded that in the excitation spectrum of CaO indirect transitions may play an important role already from Eexc = 6.5 eV. Long‐lived phosphorescence, as well as low‐temperature TL peaks at 20, 37, and ≈ 50 K of X‐irradiated CaO and CaO‐Bi monocrystals at LHeT are observed. The observed phosphorescence is interpreted as a tunneling recombination between holes and electrons, trapped, respectively, by cation vacancies (V centers) and unidentified donor centers, thermal destruction of which takes place at ≈50 K.