1. Egyptian Atomic Energy Authority,National Center for Radiation Research and Technology (NCRRT),Dep. of Radiation Engineering,Egypt,11765
2. The British University in Egypt,Faculty of Engineering,Department of Basic Science,El Sherouk City,Cairo,Egypt,11837
3. Banha University,Faculty of Engineering at Shobra,Cairo,Egypt,11672
4. The American University in Cairo,School of Sciences and Engineering,Department of Physics,New Cairo,Egypt,11835