[1] Forschungszentrum Karlsruhe, Inst Kernphys, D-76021 Karlsruhe, Germany
[2] OAW, Inst Hochenergiephys, A-1060 Vienna, Austria
[3] Univ Karlsruhe, Inst Expt Kernphys, D-76021 Karlsruhe, Germany
[4] Univ Lecce, Dept Phys, I-73100 Lecce, Italy
[5] Inst Nucl Energy Res, Sofia 1784, Bulgaria
[6] Andrzej Soltan Inst Nucl Studies, PL-90950 Lodz, Poland