1. Laboratory of Atomic, Molecular and Nuclear Physics, Department of Physics, Faculty of Science, University of Yaoundé I, P. O. Box 812, Yaoundé, Cameroon
2. The Nuclear Technology Section (NTS), Institute of Geological and Mining Research, P. O. Box 4110, Yaoundé, Cameroon
3. Department of Physics, Bertoua Higher Teachers’ Training College, University of Bertoua, P. O. Box 55, Bertoua, Cameroon