Mechanical Properties and Anisotropy in PbWO₄ Single Crystal

The mechanical properties of PbWO₄ (PWO) crystals grown by the vertical Bridgman method are systematically investigated using the microindentation technique. In the present work, the Vickers microhardness H_ν, fracture toughness K_c, yield strength σ_y and friability index B_i of PbWO₄ crystals are measured. The Vickers microhardness H_ν on the (100) wafer is about 140 MPa, which means that PWO is a little ``soft'' scintillator. The anisotropy of mechanical properties is also investigated under a steady load of 0.5 kg. The (100) wafer of the crystal exhibits combined mechanical properties more excellent than those of (111) and (001) wafers, and the values of K_c, σ_y, and B_i are 0.538 MPa・m^1/2, 51.11 kg/mm² and 284.96 νm^-1/2, respectively.