The absorption of crystals which had been doped with Cr3+ during growth, or by diffusion, was investigated before and after 105Gy of γ-irradiation and before and after proton irradiation to a fluence of 1014/cm2. It was found that Cr could also be introduced as Cr2+. Electron spin resonance measurements were made of Cr-doped crystals which had been irradiated with γ-rays and electrons. A paramagnetic peak was observed after γ- and electron irradiation. It vanished, after annealing (400C, 3h), from both optical and electron spin resonance spectra. Some Mn2+ lines were also observed, which diminished only after electron irradiation.

Radiation Defects in LiNbO3 Single Crystals Doped with Cr3+ Ions. S.M.Kaczmarek, R.Jablonski, I.Pracka, M.Swirkowicz, J.Wojtkowska, S.Warchol: Crystal Research and Technology, 1999, 34[5-6], 729-35