"Large Size Doped Lead Tungstate Scintillator and Its Preparation Technique" is awarded second prize of the National Invention Technology

The annual national science-technology award ceremony for 2007 was held at the Great Hall of the People on January 8, 2008. The project of our institute, ”Large Size Doped Lead Tungstate Scintillator and Its Preparation Technique”, is awarded second prize of the National Invention Technology. The main participants of this project are Yan Dongsheng, Yin Zhiwen, Liao Jingying, Shen Bingfu, Yuan Hui and Shao Peifa. As the honor delegate, Professor Liao Jingying went to Beijing to receive the prize.

In the early 1990s, European nucleon research center (CERN) invited us to participate in its large-scale hadron collider (LHC) international cooperation, and to research and develop lead tungstate (PbWO4, is called PWO) crystals which they need. In view of the high request of CERN and the key problems of synthesis and properties of PWO crystal, researchers expanded their work in the direction of doping technology and synthesis craft. Within 14 years’ exploration and key technologies R&D, they obtained large size and high quality doped PWO crystals in mass production which are grown successfully by the Bridgman method. And our institute is the unique unit who possesses this technology in our country.

In the doping technology aspect, researchers made the first discovery of high effective dopant -Y2O3 in the world,and put forward the innovative study on anionic-cationic co-doped PWO crystal for the first time. They invented the Y3+/F- doping technology and craft. In the preparation process aspect, researchers found that the evaporation rate of PbO is higher than that of WO3 in the PWO melt, and this conclusion has been used in real crystal growth. They invented the new technology for growing large size doped PWO crystals by the modified Bridgman method. They made integration innovations in the directions of pre-synthesis of raw materials, furnace design, temperature field design, growth parameters and so on.

The properties of PWO crystals of this project reach international leading level, which have obtained several science and technology achievements with independent intellectual properties. Quantities of large size PWO crystals have been used in high-energy physics projects and famous international scientific research institutions of America, Europe and Japan. These applications have fully demonstrated the competence and influence of PWO crystals in international great science projects, which brings remarkable economic and social benefits at the same time.