1. Natural and Artificial Radiation Laboratory, Department of Physics, Cheikh Anta Diop University, Dakar, Senegal
2. Institute of Applied Nuclear Technology, Cheikh Anta Diop University, Dakar, Senegal
3. Environmental Radioactivity Metrology Laboratory, Nuclear Safety and Radiation Protection Institute, Orsay, France
4. Carbon-14 Laboratory, Cheikh Anta Diop University, Dakar, Senegal