X-ray excited luminescence of Sr1−xEuxF2+x solid solutions

X-ray excited luminescence of SrF2 revealed a sharp and a broad emission band at 231.5 and 316.5 nm respectively while the presence of small concentrations of Eu+3 in SrF2 showed emission bands at 301 and 417 nm. Increase in europium concentration resulted in sharp bands towards red region around 593, 617, 693 and 702 nm and suppressed the broad bands at 301 and 417 nm. The emission bands at 231.5, 316.5 nm in SrF2 and 275, 301 nm in Sr1-XEuXF2+X are attributed to host emission and ionization of VK centers due to fluorine ions while the others are characteristic emission bands of europium. An energy transfer from the host as well as VK centers emission may be responsible for exciting europium and resulting sharp emissions towards red region.