Coincident event detection for advanced spectroscopy in transmission electron microscopy.

Many materials around us show properties that depend in a sensitive way on small amounts of foreign atoms in an environment of majority atoms. Transmission electron microscopy is a very powerful method to study the atomic structure of materials down to the atomic scale, and spectroscopic methods allow to pinpoint the types of atoms present. Two spectroscopic methods, EELS and EDX, are commonly used and rely on the excitation of the atoms when interacting with a beam of accelerated electrons. Both methods however have significant shortcomings, especially when it comes to obtaining detailed information on these all-important minority atoms. In this project, we propose to make use of recent developments in detectors for electrons and X-rays that form the basis of these spectroscopic methods. We propose to collect atomic excitation events in a time resolved fashion, which allows us to select those events where both an electron and X-ray is detected at the same time. In doing so, we join the benefits of both EELS and EDX methods and dramatically improve the performance of these spectroscopic methods in cases where small amounts of atoms are present in an environment of a majority of other elements. We will test the benefits of a prototype setup on several types of materials that are relevant for society: modern engineering alloys, materials for future quantum computers and semiconductors for electronics and photovoltaic applications.

Keywords:ELECTRON MICROSCOPY

Disciplines:Electronic (transport) properties, Metrology, Nanophysics and nanosystems, Optical properties and interactions with radiation, Spectroscopic methods