1. Department of Technical Services, National Radiation Protection Agency, Yaoundé, Cameroon
2. Laboratory of Nuclear Physics, Department of Physics, Faculty of Science, University of Yaounde I, Yaounde, Cameroon
3. Nuclear Technology Section, Energy Research Laboratory, Institute of Geological and Mining Research, Yaounde, Cameroon
4. Direction Générale de la Radioprotection et de la Sûreté Nucléaire, Ministère des Mines, de l’Energie et des Ressources Hydrauliques, Libreville, Gabon