A study was reported of the influence of illumination on generation and decay of point defects in TeO2 crystals following electron irradiation at ~400K. Electron irradiation was believed to cause a large concentration of diamagnetic O vacancies denoted by VOx and a smaller concentration of vacancies with one trapped electron denoted by VO.. When the sample was UV illuminated at 330nm and 77K or lower, electron spin resonance measurements showed that the number of VO. centers increased and a comparable gain of VO’ centers (3 electrons in the vacancy) occurred. A brief illumination at 660nm caused the VO’ signal to disappear and the VO. signal to decrease and return to its original value. Changes in the crystal’s optical absorption obtained from spectra measured with polarized light were given. When VO’ centers were removed by bleaching, or by thermal annealing, broad bands at 600 and 700nm disappeared and there were increased in optical absorption at 380, 440 and 480nm. These processes were reversed by a new UV illumination at 330nm and 77K. The growth and decay kinetics of VO’ centers and VO. centers measured by electron spin resonance indicated the same rates of percentage change in their concentrations. Explanation of these reversible processes supported selected models for the three different vacancy centers.Paramagnetic and Diamagnetic Defects in e- and UV-Irradiated TeO2 Single Crystals. A.Watterich, L.A.Kappers, O.R.Gilliam, R.H.Bartram, I.Földvári, L.Korecz: Nuclear Instruments and Methods in Physics Research Section B, 2002, 191[1-4], 261-5