Scintillation characteristics of PbWO4 single crystals doped with Th, Zr, Ce, Sb and Mn ions

In our previous papers we reported that La3+, Gd3+, Y3+, and Lu3+ dopings significantly improve the optical and scintillation characteristics, including radiation hardness, of PbWO4 single crystals. The hypothesis of Pb2+ deficiency in the grown crystals and its charge compensation by the mentioned trivalent ions occupying the Pb2+ sites has been proposed to explain the observed improvement. Under such assumption, tetravalent-ion doping may be as efficient as or even more efficient than trivalent-ion doping in improving PbWO4 scintillator. Recently we extended the dopant ions to stable tetravalent ions (Th4+, Zr4+) and some other ions (Ce3+,4+, Sb3+,5+, Mn2+). We have found that the tetravalent-ion (Th4+) doping gives similar improvement compared with the trivalent-ion doping in consistency with the expectation mentioned above. The ions with two different possible charge states (Ce3+,4+, Sb3+,5+) gave finite but much less improvement than the trivalent and tetravalent ions. Ce3+,4+ doping reduced the light yield significantly. Annealing of undoped PWO in PbO vapour was also studied to examine the possibility of reducing the Pb2+ deficiency