BAB Alawad

Department of Physics, University of Pretoria 0028, South Africa
Department of Physics, Sudan University of Science and Technology, Khartoum, Sudan

S Biira

Department of Physics, University of Pretoria 0028, South Africa

H Bissett

Applied Chemistry Division, South Africa Nuclear Energy Corporation (Necsa), P.O Box 582, Pretoria 0001, South Africa

JT Nel

Applied Chemistry Division, South Africa Nuclear Energy Corporation (Necsa), P.O Box 582, Pretoria 0001, South Africa

TT Hlatshwayo

Department of Physics, University of Pretoria 0028, South Africa

PL Crouse

Department of Chemical Engineering, University of Pretoria 0028, South Africa

JB Malherbe

Department of Physics, University of Pretoria 0028, South Africa