1. Research Centre for Nuclear Science and Technology, Institute of Geological and Mining Research, Yaoundé, Cameroon
2. Laboratory of Electrical and Electronic systems, Department of Physics, Faculty of Science, University of Yaoundé I, Yaoundé, Cameroon
3. Nuclear Physics Laboratory, Faculty of Science, University of Yaoundé I, Yaoundé, Cameroon
4. Department of Radiation Science, Graduate School of Health Sciences, Hirosaki University, Hirosaki, Aomori, Japan