Trapping of electrons by H super(+) in the x-ray storage phosphor Ba sub(3)(PO sub(4)) sub(2):Eu super(2+), La super(3+)

When co-doped with La super(3+), Ba sub(3)(PO sub(4)) sub(2):Eu super(2+) shows an intense thermally stimulated luminescence after x-ray irradiation. The phosphor is also optically stimulable. The stimulated emission is due to the Eu super(2+) ion. In the absence of Eu super(2+) a broad emission band is observed which is tentatively ascribed to a phosphate group close to the La super(3+) ion. EPR reveals the presence of H super(0) after irradiation. It is concluded that the substitution of La super(3+) on a Ba super(2+) site is accompanied by the introduction of H super(+) into the lattice. The latter ion acts as an electron trap; detrapping yields the stimulated luminescence.