[1] Comissao Nacl Energia Nucl IPEN CNEN SP, Inst Pesquisas Energet & Nucl, BR-05508000 Rio De Janeiro, SP, Brazil
[2] Univ Barcelona, Fac Fis, ECM, E-08028 Barcelona, Spain
[3] Univ Barcelona, Fac Fis, ICC, E-08028 Barcelona, Spain
[4] Univ Fed Pernambuco, Dept Energia Nucl, BR-50740540 Recife, PE, Brazil