The estimation of size of gigantic ions of chromium in corundum lattice

Some TL glow peaks appear in corundum crystals subjected to ionizing irradiation. The highest temperature TL peak at about 600 K, is due to chromium impurity. The non-chromium TL peaks are suppressed at an increase of chromium concentration. They disappear completely at a sufficiently low chromium concentration because of an anomalous big capture cross-section of charge carriers by chromium ions. The free charge carriers capture radius was estimated from dependence of TL intensity of non-chromium TL glow-peaks on the chromium concentration. It was equal to 4.2 nm.