A Data-Driven Workflow for Preprocessing, Anomaly Detection, and Simulation-Guided EXAFS Analysis of Cu in Steel

5 Jan 2026, 15:56
3m
Siemens Auditorium (ETH Zurich)

Siemens Auditorium

ETH Zurich

Campus Hönggerberg
Poster and Flash Presentation Flash Presentations

Speaker

Duc-Chau Nguyen (ALBA Synchrotron - CELLS)

Description

We present an integrated workflow for X-ray Absorption Spectroscopy (XAS) data processing, designed for extensible, automated analysis using Python. First, we developed a two-pass rolling median filter (with windows of 21 and 7 points and median absolute deviation thresholds of 6 and 5, respectively) to detect glitches from the incident intensity signal (I₀). The identified glitches are then removed from both I₀ and the fluorescence signal (If), yielding clean spectra for subsequent analysis. Second, we applied Z-score normalization to the absorption spectra, followed by interpolation onto a common energy grid, and then performed Principal Component Analysis (PCA) for unsupervised exploration of spectral variation across measurements. PCA reduces dimensionality, highlights systematic changes, clusters related scans, and flags outliers for inspection. Next, we applied this workflow to Cu K-edge (8.979 keV) XAS in fluorescence mode for 22MnB5 steel sheets with 0.1–0.3 wt.% Cu. Larch-based extended X-ray absorption fine structure (EXAFS) simulations were used to assess the impact of k-range on data quality. Comparing simulated EXAFS data with kmax ≈ 11 Å⁻¹ and extended k-ranges shows that higher-k measurements improve amplitude and resolution, enabling better discrimination between structural models. This modular pipeline provides a reproducible framework for XAS analysis, expandable with additional preprocessing and machine learning techniques.

Author

Duc-Chau Nguyen (ALBA Synchrotron - CELLS)

Co-authors

Dr Seyedeh Leila Panahi (ALBA Synchrotron - CELLS) Dr Marc Raventós (ALBA Synchrotron - CELLS) Dr Oleg Usoltsev (ALBA Synchrotron - CELLS) Dr Núria Bagués (ALBA Synchrotron - CELLS) Dr Jaume Pujante (Eurecat, Center Tecnologic de Catalunya Unit of Metallic and Ceramic Materials, Placa de la Ciencia 2, Manresa,08243, Spain) Dr Surya Kumaran (Arcelormittal maizieres Research SA, Rue Andre Campra 6 Immeuble Cezanne, Saint Denis, 93200, France) Dr Joaquín Otón (ALBA Synchrotron - CELLS)

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