1. Chemical
Metrology, Measurement Science and Standards, National Research Council Canada, Ottawa, Ontario K1A 0R6, Canada
2. State
Key Laboratory of Geohazard Prevention and Geoenvironment Protection, Chengdu University of Technology, Chengdu, Sichuan 610059, China
3. College
of Earth Sciences, Chengdu University of Technology, Chengdu, Sichuan 610059, China
4. Ionizing
Radiation Standards, Measurement Science and Standards, National Research Council Canada, Ottawa, Ontario K1A 0R6, Canada