Radiation stability of M1-xPrxF2+x (M = Ca, Sr, Ba) crystals

The radiation stability of the mixed crystals M1-xRxF2+x (M = Ca, Sr, Ba) depends on types of the alkaline-earth and rare-earth ions. Different to Eu- and Ce-containing systems, M1-xPrxF2+x solid solutions have a low radiation resistance, which may be associated with hole trapping on praseodymium ion according to the reaction Pr3+ → Pr4+ which is typical for praseodymium. The coloration efficiency of M1-xPrxF2+x crystals grows in the row Ca → Sr → Ba, which is explained satisfactorily within the model of rare-earth clusters, the structure of which is determined by the ratio of the base alkaline-earth cation to the praseodymium ion radii.