[1] Univ Mainz, Inst Kernphys, D-55099 Mainz, Germany
[2] TH Darmstadt, Inst Kernphys, D-64289 Darmstadt, Germany
[3] Univ Calif Los Alamos Natl Lab, Div Phys, Los Alamos, NM 87545 USA
[4] Univ Ljubljana, Jozef Stefan Inst, Ljubljana, Slovenia
[5] Rutgers State Univ, Dept Phys & Astron, Piscataway, NJ 08855 USA
[6] Arizona State Univ, Dept Phys & Astron, Tempe, AZ 85287 USA
[7] State Univ Ghent, Dept Subatom & Radiat Phys, B-9000 Ghent, Belgium