Luminescence of ⁵D₃ and ⁵D₄ levels of Tb³⁺ in borate, phosphate and tungstate glasses excited by cathode rays as a possible tool for the study of surface fluorescence in glasses

Borate, phosphate and tungstate glasses doped by Gd³⁺, Tb³⁺ and Eu³⁺ were excited by cathode rays. As a result of this, fluorescence identical with the fluorescence of glasses excited by optical means, was observed. In the Tb³⁺ doped glasses strong fluorescence from ⁵D₃ level was obtained. This fluorescence was not observed under optical excitation with the Tb³⁺ concentration studied. The absence of quenching of the ⁵D₃ level is discussed. It is proposed that cathode ray excitation can be used as an instrument for studying surface fluoresence in glasses.