ENDOR investigation of the Eu2+ activator in the X-ray storage phosphor BaFBr

Electron paramagnetic resonance (EPR) and electron nuclear double resonance (ENDOR) have been used to investigate the surrounding of the activator ion Eu2+ in single crystals of the X-ray storage phosphor BaFBr. An analysis o f the Eu2+ superhyperfine interaction with the next fluorine neighbours sho wed that Eu2+ substitutes for Ba2+ and is not shifted from a regular positi on within experimental error, in spite of the large difference in ionic rad ii. EPR and ENDOR investigations on BaFBr:Eu2+ powders established that dif ferent methods of producing these materials have no influence on the local environment of Eu2+.