About XRF tomography at XFM
XRF tomography allows the elemental rendering of 3D volumes at micron scale lengths, which sets it apart from absorption contrast tomography with which you may be familiar. XRF tomography is now offered as a standard user measurement at XFM and is scheduled to be offered at the Nanoprobe beamline within 2027.
An XRF tomography measurement requires significant investment in sample preparation and mounting as well as of order 100-fold increase in experimental (beam) time. Accordingly, proposals should only request XRF tomography if there is a strong case for this modality, and all other options have been exhausted. A 2D XFM experiment would be an excellent precursor to tomographic analysis.
XRF tomography samples need to be small, on the order of hundreds of microns in diameter and typically have a light organic matrix, so the XRF can escape from within the sample (self-absorption is minimized; see de Jonge and Vogt, below).
XRF tomography references:
E Lombi et al. Fast X-Ray Fluorescence Microtomography of Hydrated Biological Samples. Plos ONE 6 (2011) e20626
G McColl et al. Caenorhabditis elegans Maintains Highly Compartmentalized Cellular Distribution of Metals and Steep Concentration Gradients of Manganese. PloS ONE 7 (2012) e32685
MD de Jonge & S Vogt. Hard X-ray fluorescence tomography - an emerging tool for structural visualization. Current Opinion in Structural Biology. 20 (2010) 606
AJ Berry et al. Wetted two-grain boundaries in olivine aggregates and seismic velocities in the oceanic upper mantle. Earth and Planetary Science Letters 651 (2025) 119119
doi:10.1016/j.epsl.2024.119119.
A-M Carey et al. A review of recent developments in the speciation and location of arsenic and selenium in rice grain. Analytical and Bioanalytical Chemistry 402 (2012) 3275
General introduction to elemental imaging in plants including XRF tomography:
PM Kopittke, et al. Synchrotron-Based X-Ray Fluorescence Microscopy as a Technique for Imaging of Elements in Plants. Plant Physiology 178 (2018) 507 https://academic.oup.com/plphys/article/178/2/507/6116539
