Scintillation characteristics of Lu3 Al5 O12: Ce optical ceramics

Optical absorption, luminescence, and scintillation characteristics of Lu3 Al5 O12: Ce optical ceramics were measured and compared with an analogous high quality single crystal. Optical absorption of the former shows an additional light scattering loss due to nanovoids and/or refraction index inhomogeneities. Even though radioluminescence intensity of the optical ceramics prepared by a coprecipitation route exceeds that of single crystal, its scintillation light yield is lower due to the charge carrier retrapping in the process of energy transfer towards the Ce3+ emission centers. Retrapping processes are evidenced by thermoluminescence measurements below room temperature. Lu3 Al5 O12: Ce optical ceramics does not show the presence of the LuAl antisite defects which decreases the scintillation figure of merit in single crystals grown from the melt [M. Nikl, Phys. Status Solidi A 202, 201 (2005)]. Furthermore, using the ceramic technology, one can achieve both the homogeneous doping and higher Ce concentration. Similar to Y3 Al5 O12: Ce, the optical ceramics may therefore become competitive to the Lu3 Al5 O12: Ce single crystals, if trapping phenomena at other defects can be further reduced.