Electron Diffraction Based Nano-Metrology

Lead Research Organisation: University of Cambridge
Department Name: Materials Science & Metallurgy


This project is based on the development and application of a new form of electron
microscopy, namely scanning electron diffraction (SED) microscopy, a technique in
which a fine-scale (nm-sized) electron probe is scanned across a region of interest
and electron diffraction patterns are acquired at every point in the scanned area. The
remarkably rich dataset this produces provides a wealth of crystallographic data that can
be used to determine atomic structure, the presence of defects and the local
microstructure. In particular, by carefully analysing subtle distortions in the electron diffraction pattern, one can measure a local strain tensor with nanometer spatial resolution. In this project, I wish to build on successful initial results to develop strain mapping into a true nano-metrological technique, improving the robustness and sensitivity of the strain determination and quantifying the limits of the practice."


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Johnstone DN (2020) Density-based clustering of crystal (mis)orientations and the Python library. in Journal of applied crystallography

Studentship Projects

Project Reference Relationship Related To Start End Student Name
EP/N509620/1 01/10/2016 30/09/2021
1937212 Studentship EP/N509620/1 01/10/2017 30/09/2021 Phillip Crout
Title Python for Electron Microscopy: pyxem, diffsims and orix 
Description pyxem provides an open source framework for the interpretation of S(P)ED data. This is complemented by diffsims, a TEM simulation package written in pure python and orix, an orientation data analysis package. 
Type Of Technology Software 
Year Produced 2019 
Open Source License? Yes  
Impact The software remains in its infancy, but with over 6000 downloads (pyxem) at time of writing it seems very likely the packages will soon find users beyond its developers and their collaborators. 
URL https://github.com/pyxem/pyxem