Atomic Scale Resolution Electron Tomography: Data Analysis, Projection Alignment and 3D Reconstruction

Electron tomography is a powerful technique that enables to determine the 3D internal structure of a sample from a tilt series of 2D projections. Although current aberration-corrected transmission electron microscopes can achieve a resolution of 0.5 Å, radiation damage, projection misalignment and the “missing wedge” problem (i.e. specimens cannot usually be tilted beyond ±79°) have previously limited the resolution of general electron tomography to ~1 nm. Discrete tomography has recently been used to generate a 3D atomic reconstruction of a silver nanoparticle 2-3 nm in diameter, but this statistical method assumes prior knowledge of the particle’s lattice structure and requires that the atoms fit rigidly on that lattice.