Characterization and optimization of new high-quality inorganic fibers made of LuAG:Ce and LYSO:Ce

For the use in high energy physics detectors as well as in medical imaging applications several concepts have been developed in the last years, using the advantages of highly granular active detector components. Pulling inorganic fibers by the micro pulling down method provides a relatively fast and cost efficient method to provide such highly granular detector components in form of inorganic scintillation crystals. This paper will present some important aspects of the progress which has been made in optimizing the quality of fibers made of LuAG:Ce and LYSO:Ce. Based on these optimizations it became possible to reduce the attenuation coefficient from the initial value of > 1.0 cm^-1 by more than one order of magnitude, down to 0.02 cm^-1 for the best samples. In addition firsts results on the radiation hardness of inorganic LuAG:Ce fibers to 150 MeV protons will be presented. As a reference for the fibers, also small rectangular rods cut from large crystals, grown by conventional methods have been characterized and compared to the fibers.