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SUMMARY:Physics-guided NMF for the analysis of STEM/EDXS data : from raw d
 ata to quantified chemical phases.
DTSTART:20220113T131500
DTEND:20220113T140000
DTSTAMP:20260916T120422Z
UID:47dbd66bd5a226cc61d247b45f6bd0c00bdd79b1ad914261a3892753
CATEGORIES:Conferences - Seminars
DESCRIPTION:Dr. Adrien Teurtrie\, SB IPHYS LSME\nEnergy-dispersive X-ray s
 pectroscopy (EDXS) in the scanning transmission electron microscope (STEM)
  is a useful tool for the local chemical analysis at the nanoscale. Using 
 the scanning mode it is possible to acquire a so-called spectrum-image whi
 ch is a 3D datacube with an EDXS spectrum at each position of the scan. In
  the simplest cases it is straightforward to obtain a chemical map by inte
 grating some part along the energy axis. Often\, the spatial overlap betwe
 en phases with different chemistry or the spectral overlap between X-ray c
 haracteristics peaks make the analysis of STEM/EDXS spectrum images a comp
 lex task. A few decomposition algorithms\, such as Principal Component Ana
 lysis (PCA) or Non-Negative Matrix Factorization (NMF)\, are commonly used
  to retrieve the pure phases and their distribution in the sample from STE
 M/EDXS data. However\, the outputs of these methods tend to contain artefa
 cts and lack accuracy.\nTo address these issues we designed an improved ve
 rsion of the NMF that incorporates a physical model of the EDXS into the d
 ecomposition. Using this new algorithm\, it is possible to obtain an accur
 ate decomposition of a spectrum-image in pure phases as well as a chemical
  quantification of each phases.\nIn this presentation we will demonstrate 
 the operating principle of the algorithm. We will also show a comparison o
 f the performances of our algorithm with those in the literature on both s
 imulated and experimental data.
LOCATION:https://epfl.zoom.us/j/63992244026
STATUS:CONFIRMED
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