Dynamic automation in transmission electron microscopy: application to electron holography

Abstract

Instrumental and methodological developments in electron microscopy have always been an active subject of research. The continuous instrumental development, in particular with the advent of new brighter electrons sources, sensitive cameras(direct electron detection), aberration corrector , high collection angle EDX detector,... has led to the emergence of new methods of observation by original techniques. In parallel of these development, automation of the electron microscope is a growing research area. Algorithms were first developed for focusing and astigmatism correction, leading to computer-assisted alignment of higher order aberrations for spherical-aberration-corrected TEM. Automation was extended to acquire tomographic tilt series for cryo-microscopy, diffraction tomography, and holographic tomography, and recording images of many specimen areas and defocus values for single-particle analysis in cryo-microscopy. Further refinements include object displacement and focus prediction to accelerate acquisition of tilt series for shorter acquisition and less beam induced damage , online reconstruction of tilt series for preliminary inspection of data at the microscope, alignment of individual particles in images to correct for beam induced movement...