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David Shuh1 Lingfeng He2 Mitchell Meyer2 Jason Harp2 Claude Degueldre3

1, Lawrence Berkeley National Lab, Berkeley, California, United States
2, Idaho National Laboratory, Twin Falls, Idaho, United States
3, Lancaster University, Lancaster, , United Kingdom

Soft X-ray synchrotron radiation methodologies are being employed at the Advanced Light Source (ALS) of Lawrence Berkeley National Laboratory (LBNL) to characterize radioactive and actinide materials using spectromicroscopy approaches developed for the nanoscience investigations. Results from these studies have begun to provide improved fundamental knowledge that can be used as a scientific basis for the enhanced design of actinide materials, complexes, ligands, and the overall understanding of actinide materials. The experimental developments at the ALS have centered on studies of radioactive materials with the Molecular Environmental Science (MES) soft X-ray scanning transmission X-ray microscope (STXM) at Beamline 11.0.2 for spatially-resolved near-edge X-ray absorption spectroscopy (XAS). The spectromicroscopy capabilities of the STXM provide the means to determine the speciation and composition in a range of actinide materials, particularly those of technological and environmental interest with spatial resolution that can reach to the true nanoscale. A particular emphasis has been on the use of light atom (B, C, N, O, F, Na, Mg, Al, Si) ligand K–edge XAS technique to determine the electronic structure characteristics in an array of unique and relevant materials. Furthermore, there are a host of additional electron energy level thresholds (such as the L–edges of the transition metals, the M–edges of the lanthanides, and others) that can be probed by near-edge XAS in the soft X-rays. A key component of the aforementioned STXM spectromicroscopy investigations has been the partnership with theory that has provided the fundamental basis from which to interpret and more fully understand the information contained within the near-edge XAS spectra. Contemporary STXM spectromicroscopy studies have focused on fundamental studies of the electronic structure in actinide complexes, speciation of radioactive elements in environment, forensic science, and most recently to fast ion beam (FIB) prepared radioactive materials specimens in collaboration with Idaho National Laboratory. Future scientific developments and applications of soft X-ray STXM spectromicroscopy investigations utilizing ptychography methodologies will be discussed.

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