[1] Ctr Nacl Aceleradores, E-41092 Seville, Spain
[2] Univ Sevilla, Dpto Fis Atom Mol & Nucl, E-41080 Seville, Spain
[3] Univ Nacl Autonoma Mexico, Inst Fis, Mexico City 01000, DF, Mexico
[4] Univ Nacl Autonoma Mexico, Inst Invest Antropol, Mexico City 04510, DF, Mexico