Niels Cautaerts

ALPHABETA is an open‐source program we developed to make the life of transmission electron microscope users easier. Work on the transmission electron microscope, or TEM, is done by correctly orienting a thin sample with respect to the electron beam. The orientation determines how images made from the sample will look. Studying a sample may require the user to orient it in multiple different ways. This orienting must be done by adjusting ‘tilt’ parameters of the stage on which the sample sits in the microscope. Correctly adjusting these tilt parameters to obtain the correct orientation is a job that requires practice and experience. Our program should facilitate this step of working with the microscope, because it calculates the tilt parameters to achieve a certain orientation. This paper describes the mathematics behind the software and provides some examples from the work of the authors. We also evaluate how accurate the calculation is. The examples included are orienting to different zone axes, which are special crystal orientations, and making a series of images that provide a 3D effect when played after each other of particles that can only be visualised in particular orientations.