1. Institute of Plasma Physics, HFIPS, Chinese Academy of Sciences, P.O. Box 1126, Hefei 230031, P. R. China
2. University of Science and Technology of China, Hefei 230026, P. R. China
3. State Key Laboratory of Radiation Medicine and Protection, School for Radiological and Interdisciplinary Sciences (RAD-X) and Collaborative Innovation Center of Radiation Medicine of Jiangsu Higher Education Institutions, Soochow University, Suzhou 215123, China
4. The 404 Company Limited China National Nuclear Corporation, Jiayuguan 735100, China