[1] SLAC Natl Accelerator Lab, Stanford, CA 94035 USA
[2] Dept Appl Phys, Stanford, CA 94035 USA
[3] Dept Mat Sci & Engn, Stanford, CA 94035 USA
[4] SLAC Natl Accelerator Lab, 2575 Sand Hill Rd, Menlo Pk, CA 94025 USA
[5] Western Digital Co, HGST, 3403 Yerba Buena Rd, San Jose, CA 95135 USA
[6] Dept Phys, Stanford, CA 94035 USA
[7] European XFEL GmbH, Albert Einstein Ring 19, D-22761 Hamburg, Germany