1. Lawrence Livermore National Laboratory, Livermore, California 94550, USA
2. Directorate of Research and Applied Science, AWE plc, Reading RG7 4PR, United Kingdom
3. NASA Goddard Space Flight Center, 8800 Greenbelt Rd., Greenbelt, Maryland 20771, USA
4. Max-Planck-Institut für Kernphysik, Saupfercheckweg 1, D-69117 Heidelberg, Germany