Fig. 6 Images of an NCD ball before and after the FIB milling. Images of an NCD ball before and after the FIB milling. (A) Secondary electron image of a ball before ion milling, as taken in the Scios DualBeam system (FEI Deutschland GmbH) at a voltage of 20 kV and a current of 0.8 nA. mag, magnification; Det, detector; ETD, Everhart Thornley detector; HV, high voltage; HFW, horizontal field width. (B) Gallium ion image of the same ball (taken at 30 kV and 30 pA) after milling at 30 kV and 5 nA. Natalia Dubrovinskaia et al. Sci Adv 2016;2:e1600341 Copyright © 2016, The Authors