Feng, XQ (reprint author), Chinese Acad Sci, Shanghai Inst Ceram, State Key Lab High Performance Ceram & Superfine, Shanghai 200050, Peoples R China.
Heavily trivalent ions doped into PbWO4 will exert a distinct influence on the scintillation performance and the conductivity of the crystal. In the light of the doping mechanism, the microstructure of the heavily La3+ doped and undoped PbWO4 crystals was studied using extended X-ray absorption fine structure (EXAFS) and X-ray Photoelectron Spectroscopy (XPS). When heavily doped, La3+ may substitute the W sites as well as the Pb2+ sites for self-compensation by forming La dimers or La small aggregates, which results in a significant decrease in the light yield. Another charge compensator, the interstitial oxygen ion, was also observed and is discussed in this paper.