Effect of γ-irradiation on the lattice parameter and colour centre concentration in pure Ca2+, Sr2+ and Eu2+ doped KCI crystals

The changes of lattice parameter and colour centre concentration are examined in KCI crystals (both pure and Me²⁺-doped) irradiated by γ-rays at room temperature. For the pure crystals the relative volume change vs. F-centre concentration plot reveals the presence of two stages, one ascribed to the introduction of colour centre pairs (or F centres only) and other to the generation of the new dislocations (or new dislocations with trapped-hole centres). In Me²⁺ doped crystals the lattice expansion bears a complex character (in the initial irradiation stage a transient maximum appears). Additional anomaly appears in Eu²⁺ KCI in the high-dose range where in spite of a distinct F-centre concentration drop a marked raise of the lattice parameter is observed.