Room Temperature Investigation of the Photostimulated Afterglow in KCl:Eu2+ Crystals

KCl:Eu2+, γ‐irradiated at room temperature, is known to luminesce on photoexcitation in the F band with the emission spectrum of the impurity ion. Several experiments are made now: firstly, the emission—excitation spectrum is found to exhibit a peak at about 600 nm. Secondly, the samples are excited with the SH of a mode‐locked Nd glass laser. The maximum emission response occurs delayed at about 400 ns relative to the laser‐pulse peak. The luminescent quantum yield is estimated to be about 1%. The decay kinetics of the phosphorescent tail is also followed. A tentative model is discussed in which the luminescence results from a two‐step electron tunneling between excited F and Eu levels.