1. Radiochemistry
Lab, School of Nuclear Science and Technology, Lanzhou University, 730000 Lanzhou, P. R. China
2. Center
for Nuclear Technologies, Technical University of Denmark, DTU Risø Campus, DK-4000 Roskilde, Denmark
3. Key
Laboratory of Special Function Materials and Structure Design, Ministry
of Education, Lanzhou University, 730000 Lanzhou, P. R. China
4. Xi’an
AMS Center, State Key Laboratory of Loess and Quaternary Geology,
Institute of Earth Environment, Chinese Academy of Sciences, 710061 Xi’an, P. R. China