On glow curves obtained by ionizing and non‐ionizing radiation

Two distinct groups of glow peaks have recently been observed in nominally pure, uv excited alkali halides. These glow peaks are investigated in comparison with those obtained by X‐irradiation. Different processes are assumed to be responsible for the excitation of the thermoluminescence (TL) emitted at the various peaks. One process, which is connected with the creation of Frenkel pairs, causes the excitation of TL by uv light in the region of the first exciton band. This process appears also to be dominant in the excitation of “virgin”, pure samples by X‐rays. Another process is involved in the excitation of TL by ionizing uv light. This excitation, which is restricted in this case to a thin surface layer, is attributed to the presence of oxygen impurities and the generation of V_K centres.