PREMIER CAT - Enhancing the signal-to-noise ratio of EELS for quantitative EMCD measurements through compressive sensing
EMSL Project ID
49245
Abstract
Electron magnetic chiral dichroism (EMCD) is the electron wave analogue of X-ray magnetic circular dichroism (XMCD). It offers the possibility to study magnetic properties at the nanoscale in a transmission electron microscope (TEM). In a 'classical' EMCD setup, the sample is illuminated with an electron plane wave and acts as a beam splitter. Although it is meanwhile established that EMCD allows for the measurement of magnetic dichroism, only few examples are available that present quantitative results. Despite some progress in the field, the main challenge of quantitative EMCD remains to be the limited signal-to-noise (S/N) ratio of electron energy loss (EEL) spectra, which is inherent to EMCD experiments. While in recent approaches, the main focus lies on the optimization of the EMCD experiment itself less attention is paid to the post-acquisition analysis of the EEL spectra. Here, compressive sensing offers the possibility to reconstruct an experimental spectrum with a limited basis set using Bayesian mathematics to separate the “true” absorption edges of interest from contributions to the spectra such as the white noise of the CCD camera or artefacts due to sample drift and contaminations. As a consequence, the S/N ratio is expected to be significantly enhanced over that of the unprocessed spectra thereby providing data that is much more suitable for the further evaluation of EMCD.
Project Details
Start Date
2016-04-18
End Date
2016-09-30
Status
Closed
Released Data Link
Team
Principal Investigator
Team Members