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Micro-XRF is a promising method to study elemental composition of samples and objects of various nature with spatial resolution of tens of microns to tens of nanometers [1]. Application of polycapillary optics for focusing and (optionally) collecting enables conduction of studies on synchrotron radiation (SR) sources of the second and higher generation, the minimum possible spatial resolution limited to values of 10 to 25 microns (effective width of the focus of X-ray lenses, depending on the energy of transmitted radiation) [1].
At a sufficiently high signal-to-noise ratio and small scanning step, one can attain subfocus resolution (i.e., its further reduction by a factor of 2-3 [2]) via processing chemical element distribution maps using deconvolution methods [3]. However, at operation on secondgeneration SR sources, this method is applicable for processing maps only for matrix and minor elements (with relative concentration of not less than one percent) [4].
We have developed a regularization approach for situations with signal noise of medium grade. This approach correctly takes into account a priori specific information and is aimed at identifying the most general properties of composition and morphology in micro-areas less than 15 microns in size. It was tested and showed a good result for two characteristic cases of practical importance, which arose in processing of a series of maps resulting from studies of geological and cosmic samples (e.x., [4-5] and so on) using micro-XRF.
The work was carried out in the framework of the state assignment for Budker INP SB RAS and the RFBR projects no. 19-05-50046, 18-03-01251. The work was partly done at the shared research center SSTRC on the basis of the Novosibirsk FEL/VEPP-4-VEPP-2000 complex at BINP SB RAS, using equipment supported by project RFMEFI62119X0022.
[1] I. Mantouvalou, W. Malzer et al. Spectrochemica Acta Part B. 77, 2012, 9-18 [2] D.S. Sorokoletov, Ya.V. Rakshun, E.P. Voytovich et al. Physics Procedia. 84, 2016, 295-301
[3] P. Wrobel, M. Czyzycki. Talanta. 113, 2013, 62-67
[4] F.A. Darin, Y.V. Rakshun, D.S. Sorokoletov et al. Bulletin of the Russian Academy of Sciences: Physics. 83, 2019, 1433-1436
[5] F. Darin, D. Sorokoletov, Ya. Rakshun et el, Journal of surface investigation: x-ray, synchrotron and neutron techniques, 12 (1), 2018, 123-127
