1. Accelerator Technology and Applied Physics, Lawrence Berkeley National Laboratory, 1 Cyclotron Road, Berkeley, California 94720, USA
2. QCD Labs, COMP Centre of Excellence, Department of Applied Physics, Aalto University, P.O. Box 13500, FI-00076 Aalto, Finland
3. The Molecular Foundry, Lawrence Berkeley National Laboratory, 1 Cyclotron Road, Berkeley, California 94720, USA
4. Department of Physics, National University of Singapore, 2 Science Drive 3, Singapore 117551, Singapore
5. GSI Helmholtz Center for Heavy Ion Research, 64291 Darmstadt, Germany
6. Institute of Materials Physics, WWU Münster, Wilhelm-Klemm-Straße 10, 48149 Münster, Germany
7. Technical University of Darmstadt, 64287 Darmstadt, Germany