1Radek Novotný, 1,2Gunther Kletetschka, 3Filip Košek, 4Daniela Popelková
Icarus (in Press) Open Source Link to Article [DOI: 10.1016/j.icarus.2026.117299]
1Institute of Hydrogeology, Engineering Geology and Applied Geophysics, Faculty of Science, Charles University, Prague, Czech Republic
2Geophysical Institute, University of Alaska Fairbanks, United States of America
3Institute of Geochemistry, Mineralogy and Mineral Resources, Faculty of Science, Charles University, Prague, Czech Republic
4Imaging Methods Laboratory, BIOCEV, Vestec, Czech republic
Copyright Elsevier
This study investigates the response of lunar breccia minerals and selected reference materials to accelerated Ga+ ion irradiation using focused ion beam (FIB) processing combined with Raman spectroscopy. Anorthite and pyroxene bearing clasts from Apollo 15 breccias 15405 and 15445 were examined alongside monocrystalline silicon, magnetite, and pyrite to evaluate mineral specific structural modifications induced by heavy ion exposure. Samples were characterized by Raman spectroscopy before and after irradiation with 30 keV Ga+ ions at four beam currents (0.43, 0.79, 2.5, and 9.3 nA). Silicate phases exhibited band broadening, peak shifts, and partial amorphization consistent with increasing lattice disorder. Monocrystalline silicon showed progressive damage of the crystalline structure, while magnetite and pyrite displayed enhanced structural disorder and modifications of Fe-bearing spectral features. At the highest irradiation conditions, Ga implantation and local heating may have contributed to the observed changes. Based on published SRIM-derived displacement estimates, the maximum Ga+ fluence applied in this study corresponds to approximately 105–106 years of natural solar wind exposure in terms of cumulative atomic displacement damage. This estimate is intended only as an approximate comparison between laboratory irradiation and natural space weathering. Although Ga+ FIB irradiation does not directly reproduce natural solar wind conditions, it provides an accelerated approach for assessing the relative susceptibility of planetary materials to heavy ion induced structural degradation and offers implications for future spectroscopic and paleomagnetic investigations of lunar samples.