The FA(III)centers have been obtained by X-ray irradiation and light conversion in T1+:KC1 single crystals, its emmission band and excitation band lies from 1.3 to 1.7m and 0.9 to 1.2m with peaks at 1.5m and 1m respectively (77K). The light and thermal stability (R.T)of FA(III)centers decreases slowly in the first few days, and then remains unchanged, the stable FA(III)centers can be finally obtained.