1. Postgraduate School for Fundamental and Applied Sciences, University of Douala Fundamental Physics Laboratory, , P.O. Box 24157, Douala , Cameroon
2. National Radiation Protection Agency (NRPA) , P.O. Box 5331, Akwa, Douala , Cameroon
3. University of Ghana School of Nuclear and Allied Sciences, , P.O. Box AE 1, Atomic, Accra , Ghana
4. Radation Protection Institute, Ghana Atomic Energy Commission , P.O. Box LG80, Legon, Accra , Ghana
5. Radiological and Medical Science Research Institute, Ghana Atomic Energy Commission , P.O. Box LG80, Legon, Accra , Ghana
6. University of Maroua, Faculty of Science , P.O. Box 814, Maroua , Cameroon