Description
Laser-driven particle acceleration based on solid targets [1] is promising for a wide range of applications, from nuclear medicine to materials characterization. Laser-plasma radiation sources are attractive because they can generate various types of radiation (e.g., high-energy electrons, ions, neutrons, and γ-rays), allow for energy tuning, and can operate within potentially compact setups. For instance, precise control over the laser-pulse properties (e.g., intensity) and the solid-target parameters (e.g., thickness and surface conditioning) enables one to tune both the maximum ion energy and the number of accelerated ions. [2,3]. Therefore, laser-driven radiation sources represent promising alternatives to conventional accelerators which, although based on mature technologies, remain limited in terms of flexibility and compactness.
Particle Induced X-Ray Emission (PIXE) and X-Ray Fluorescence Spectroscopy (XRF) are complementary materials characterization techniques used in several fields including artworks analysis [4]. They rely on the irradiation of samples with protons and photons to induce characteristic X-ray emission. Notably, PIXE and XRF could benefit from the use of laser-plasma radiation sources [5-7]. Indeed, the energies of the accelerated particles and emitted photons from compact laser-driven particle sources are compatible with those required for the characterization of cultural heritage materials.
This contribution provides an overview of the laser-driven particle acceleration activities carried out at the Department of Energy of Politecnico di Milano [8] related to materials characterization with laser-driven particle sources. Then, we focus on the study of laser-driven PIXE and XRF techniques for the analysis of cultural heritage materials. Results obtained during an experimental campaign performed at the ELIMAIA beamline [9] (at the ELI Beamlines facility) driven by the HAPLS laser are presented. Using a proof-of-principle setup [10], laser-driven protons and photons were transported in air to irradiate certified materials, medieval bronzes, and Iron Age ceramics. We measured the characteristic X-rays emitted by the sample, and the spectra were analysed with a numerical tool that integrates the theoretical description of PIXE in the PyMCA code [11] for XRF analysis. In this way, it is possible to determine the elements present in the samples and their concentrations. This study lays the foundation for the development of laser–plasma accelerators tailored to the characterization of cultural heritage materials, suggesting that this approach could achieve results comparable to conventional sources while maintaining the inherent versatility of laser-driven systems.
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[3] I. Prencipe, et al., New Journal of Physics 23.9 (2021): 093015
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[5] F. Mirani et al., Science Advances (2021) 7-3
[6] P. Puyuelo-Valdes et al., Scientific Reports (2021) 11-9998
[7] M. Salvadori et al., Physical Review Applied (2024) 21-064020
[8] https://www.ensure.polimi.it/
[9] D. Margarone, et al. Quantum Beam Science 2.2 (2018): 8
[10] F. Gatti et al., IEEE Transaction on Instrumentation and Measurement (2024) 73-3536912
[11] V. A. Solé, et al. Spectrochimica Acta Part B: Atomic Spectroscopy 62.1 (2007): 63-68.
