TEY and FY complementary application for the analysis of Layered Samples with XAS in Cultural Heritage

XAS analysis is a great tool for investigating the local environment of an atomic species; however, like many X-ray techniques (e.g. XRF), the information collected is always an average of the whole volume investigated. Besides, the investigated volume size depends on various factors: i.e. source energy, sample density and composition, and collection mode. For example, in transmission, the whole irradiated volume is investigated, in fluorescence the volume depends on the geometry of acquisition and the fluorescence line energy, while in total electron yield, it depends on the Auger electron energy. The definition and quantification of the volume investigated may not be necessary if the sample is homogeneous. Still, it becomes crucial if we work with layered samples, as it often occurs in fields like electrochemistry (electrodes may be subjected to changes on the surface during their working cycles) or cultural heritage (where photochemical alteration processes are mostly observed on the sample’s surface).[1] In this presentation, we will talk about the advantages and issues in the analysis of layered samples in fluorescence and Total Electron Yield (TEY) mode, showing the complementarity of these two techniques in the cultural heritage samples analysis, both for punctual analyses and for mapping purposes, showing their application for the study of ceramics Luster samples.[2-4] Indeed, these samples present a complex layered structure, with various elements in different oxidation states in their layers, and can be easily employed as benchmark samples. [1] L. Monico, F. d’Acapito, M. Cotte, K. Janssens, A. Romani, G. Ricci, C. Miliani, L. Cartechini, Nuclear Instruments and Methods in Physics Research Section B: Beam Interactions with Materials and Atoms 2023, 539, 141–147. doi:10.1016/j.nimb.2023.03.040. [2] S. Padovani, I. Borgia, B. Brunetti, A. Sgamellotti, A. Giulivi, F. D’Acapito, P. Mazzoldi, C. Sada, G. Battaglin, Appl. Phys. A 2004, 79, 229–233. doi:10.1007/s00339-004-2516-2. [3] S. Padovani, C. Sada, P. Mazzoldi, B. Brunetti, I. Borgia, A. Sgamellotti, A. Giulivi, F. D’Acapito, G. Battaglin, Journal of Applied Physics 2003, 93, 10058–10063. doi:10.1063/1.1571965. [4] S. Padovani, D. Puzzovio, C. Sada, P. Mazzoldi, I. Borgia, A. Sgamellotti, B. G. Brunetti, L. Cartechini, F. D’Acapito, C. Maurizio, et al. Appl. Phys. A “XAFS Study of Copper and Silver Nanoparticles in Glazes of Medieval Middle-East Lustreware (10th–13th Century)” 2006, 83, 521–528. doi:10.1007/s00339-006-3558-4.