Differential elastic scattering cross sections, as a function of polar scattering angle, for incident electrons of energy 300 keV for (A) osmium, (B) lead, and (C) uranium atoms. This is taken from the NIST standard reference database SRD 64 (ref), and as described by Salvat et al., 2005. Angles for two objective apertures in the FEI/Thermo Fisher Scientific Tecnai TF30 TEM are indicated: a 20-μm diameter aperture subtending scattering angles of 0.005 radian, and a 40-μm diameter aperture subtending scattering angles of 0.01 radian.