Rapid aberration measurement with pixelated detectors.

Aberration-corrected microscopy in a scanning transmission electron microscope requires the fast and accurate measurement of lens aberrations to align or 'tune' the corrector. Here, we demonstrate a method to measure aberrations based on acquiring a 4D data set on a pixelated detector. Our method is compared to existing procedures and the choice of experimental parameters is examined. The accuracy is similar to existing methods, but in principle this procedure can be performed in a few seconds and extended to arbitrary order. This method allows rapid measurement of aberrations and represents a step towards more automated electron microscopy.