Induced absorption spectra were measured for similarly-grown pure or La-doped single crystals after 60Co bombardment to between 1 and 230Gy. It was found that La doping considerably increased the radiation hardness of the material, just as it was known to do in the case of iso-structural PbWO4 single crystals. The transmission of as-grown undoped CaWO4 exhibited a decrease below 450nm, and revealed the presence of deep trapping states. These trapping centres were also effectively decreased by La doping. The induced absorption bands were explained in terms of known and hypothetical colour centres in the CaWO4 and PbWO4 single crystals.

Effect of La Doping on Calcium Tungstate Crystals Radiation Hardness. S.Baccaro, P.Bohacek, A.Cecilia, V.Laguta, M.Montecchi, E.Mihokova, M.Niki: Physica Status Solidi A, 2000, 178[2], 799-804