1. Laboratory of Atomic, Molecular and Nuclear Physics, Department of Physics, Faculty of Science, University of Yaounde I, P. O. Box 812, Yaounde, Cameroon
2. Department of Physics, Faculty of Science, University of Maroua, P. O. Box 814, Maroua, Cameroon
3. Laboratory of Theorical Physics, University of Bamenda, P. O. Box 39, Bambili, Cameroon
4. Nuclear Technology Section, Institute of Geological and Mining Research, P. O. Box 4110, Yaounde, Cameroon