[1] Thomas Jefferson Natl Accelerator Facil, Newport News, VA 23606 USA
[2] Carnegie Mellon Univ, Pittsburgh, PA 15213 USA
[3] Univ Bonn, Helmholtz Inst Strahlen & Kernphys, D-53115 Bonn, Germany
[4] Johannes Gutenberg Univ Mainz, Inst Kernphys, D-55099 Mainz, Germany
[5] George Washington Univ, Ctr Nucl Studies, Washington, DC 20052 USA