Radiation color centers in Y3Al5O12:Cr3+tals

An investigation was made of the absorption and thermoluminescence spectra of color centers in a batch of yttrium aluminum garnet crystals with chromium concentrations in the range 0–0.8 %. The induced absorption in the region of 300 nm was found to be due to ionization defects in the lattice of these crystals. The absorption at 380 and 480 nm was attributed to the chromium impurity and it appeared when the chromium concentration was in the range 0.03–0.3 %. The 380 and 480 nm maxima corresponded to two types of trap with levels at 1.1 and 0.8 eV.