A general method for baseline-removal in ultrafast electron powder diffraction data using the dual-tree complex
Laurent P René de Cotret1, Bradley J Siwick
1Department of Physics, McGill University , 3600 rue University, Montréal, Québec H3A 2T8, Canada.
Structural Dynamics (Melville, N.Y.)
|January 14, 2017
Summary
Background subtraction in ultrafast electron powder diffraction (UEPD) is challenging for complex materials. The dual-tree complex wavelet transform (DTCWT) method accurately extracts diffraction intensities, even with time-varying backgrounds.
Area of Science:
- Materials Science
- Crystallography
- Data Analysis
Background:
- Ultrafast electron powder diffraction (UEPD) presents challenges in background subtraction, especially for materials with complex structures and overlapping diffraction peaks.
- Identifying pure background regions in scattering vector data is often not feasible.
Purpose of the Study:
- To evaluate background subtraction algorithms for UEPD data.
- To compare discrete and dual-tree complex wavelet transforms (DTCWT) for analyzing UEPD patterns.
Main Methods:
- Simulated UEPD data from the M1-R phase transition in Vanadium Dioxide (VO2) with a time-varying background were used.
- Performance comparison of discrete wavelet transform and DTCWT algorithms.
Main Results:
- The DTCWT approach achieved high accuracy in intensity extraction, better than 2% across the entire simulated scattering vector range.
- The accuracy of the DTCWT method was found to be independent of the delay time.
Conclusions:
- DTCWT is a robust and accurate method for background subtraction in UEPD, particularly for complex materials.
- The developed method provides reliable intensity data for time-resolved studies.
- A Python package implementing the DTCWT algorithm is available for researchers.
