1. Department of Materials Science and Engineering, Cornell University, Ithaca, NY 14853, USA.
2. Department of Radiology, Memorial Sloan-Kettering Cancer Center, 1275 York Avenue, New York, NY 10065, USA.
3. School of Applied and Engineering Physics, Cornell University, Ithaca, NY 14853, USA.
4. Kavli Institute at Cornell for Nanoscale Science, Ithaca, NY 14853, USA.
5. Department of Physics, Cornell University, Ithaca, NY 14853, USA.
6. Cornell High Energy Synchrotron Source (CHESS), Cornell University, Ithaca, NY 14853, USA.