1. Department of Nuclear Physics, National Institute of Research and Development for Physics and Nuclear Engineering "Horia – Hulubei", PO Box MG – 6, 077125 Magurele/Ilfov, Romania
2. Department of Atomic and Nuclear Physics, University of Bucharest, PO Box MG-11, 077125, Magurele/Ilfov, Romania
3. National Institute of Research and Development for Physics and Nuclear Engineering "Horia – Hulubei", PO Box MG – 6, 077125 Magurele/Ilfov, Romania
4. Department of Atomic and Nuclear Physics, University of Bucharest PO Box MG-11, 077125 Magurele/Ilfov, Romania