Time decay of stable absorption of gamma irradiated lithium niobate crystals doped by cuprum ions

The transient and stable color centers in pure and doped lithium niobate crystals (LNO) have been investigated in several works, for example in [1]. The stable color centers are centers which have lifetime higher then 1s. Unfortunately, the lifetime of color centers were studied in literature only for transient color centers, for example in [2]. In this work the lifetime of stable additional absorption induced by gamma irradiation in Cu doped of LNO crystal will be determined from data obtained during 10 years.