THERMOLUMINESCENCE OF DOPED GD3GA5O12 GARNET CERAMICS

Gadolinium gallium garnet ceramics (GGG) doped with CP3+, Pr3+ and Bi3 + have efficient luminescence. Excited by X-rays some of the investiga ted scintillators show an afterglow which is detrimental to an applica tion in medical radio diagnostics. Thermoluminescent measurements betw een 50 K and 600 K gave results that allow to estimate the trap concen tration in these materials. Only shallow traps could be found in GGG:C r. It seems that these traps are caused by lattice defects relative to oxygen deficiency. The thermoluminescence at higher temperatures of G GG:Pr and GGG:Bi reveals deep traps which determine the afterglow in t hese luminescent materials.