[1] Karlsruhe Inst Technol, Inst Kernphys, D-76021 Karlsruhe, Germany
[2] Univ Michoacana, Inst Fis & Matemat, Morelia, Michoacan, Mexico
[3] Univ Turin, Dipartimento Fis, I-10124 Turin, Italy
[4] Karlsruhe Inst Technol, Inst Expt Kernphys, D-76021 Karlsruhe, Germany
[5] Horia Hulubei Natl Inst Phys & Nucl Engn, Bucharest, Romania
[6] INAF Torino, Osserv Astrofis Torino, Turin, Italy
[7] Univ Sao Paulo, Inst Fis Sao Carlos, BR-05508 Sao Paulo, Brazil
[8] Univ Wuppertal, Fachbereich Phys, Wuppertal, Germany
[9] Univ Siegen, Dept Phys, D-57068 Siegen, Germany
[10] Radboud Univ Nijmegen, Dept Astrophys, NL-6525 ED Nijmegen, Netherlands
[11] Natl Ctr Nucl Res, Dept Astrophys, Lodz, Poland
[12] Univ Bucharest, Dept Phys, Bucharest, Romania