Development on non-destructive muonic X-ray analysis:Appication to Earth and Planetary Science
K. TERADA1, A. SATO1, K. NINOMIYA1, Y. KAWASHIMA1, K. SHIMOMURA1, 2,D. Tomono1, G. YOSHIDA1, Y. KAWAI1, T. OSAWA3 and S. TACHIBANA4
1

Osaka University, 2High Energy Accelerator Research Organization.
3
Japan Atomic Energy Agency and 4Hokkaido University

The muon is a lepton with a mass of 105.7 MeV/c2, approximately 200 times heavier than the electron. So far,electron-induced characteristic X-ray analysis has been widely used to determine chemical compositions of materials in Earthand Planetary Science. In recent years, analysis of characteristic X-rays from muonic atoms, in which a muon is captured, hasattracted attention because both a muon beam and a muon-induced characteristic X-ray have high transmission abilities, ofwhich energies are about 200 times higher (e.g., muonic carbon-Kα is 75keV, whereas electron-induced carbon-Kα is 0.3keV). It is known that muonic X-ray analysis has great advantages in several ways; (1) non-destructive elemental analysis fromlight to heavy elements, (2) depth profile analysis, (3) isotopic measurement for heavy elements and (4) investigation ofchemical condition (redox-state). Such a non-destructive muonic X-ray analysis has a great potential to characterize precious
extraterrestrial samples returned by spacecrafts such as Hayabusa2 and OSIRIS-REx in 2020’s.
Following our successful detection of muonic X-ray spectra from carbonaceous chondrites, Murchison and Allendewith intense pulsed Muon beam at J-PARC [1], we have developed on muonic X-ray analysis at the MuSIC (MuSIC; MUon
Science Innovative Channel at Osaka University, [2, 3]), and obtained the fundamental data for quantitative analysis ofplanetary materials [4]. Using one of the world-leading intense direct current muon beam source, we successfully detectedcharacteristic muonic X-rays of Mg, Si, Fe, O, S and C from Jbilet Winselwan CM chondrite, of which carbon content is about
2 wt%, and the obtained elemental abundance pattern was consistent with that of CM chondrites. We also checked Muon
irradiation damage of pellets of mixed organic chemical reagents (alanine, glucose, paraformaldehyde, phenanthrene, andstearic acid) after 3–12 hour exposure to check the irradiation damage, and confirmed that they do not show any systematicchanges with either the exposure time or the depth, and are not different from those of non-exposed samples within thevariation of initial reagent mixtures. We also performed the muonic X-ray analysis of terrestrial PbS (Galena) for Pb isotopes
measurement and iron meteorite to check the feasibility of chemical condition (redox-state) measurement. At the symposium,we will report on our recent progress of muonic X-ray analysis and discuss on a future prospect for applications for earth andplanetary science.

Figure 1: Direct-current Muon beam line at MuSIC, Osaka University.

Figure 2: Muonic X-ray spectra of Jbilet Winselwan CM2 chondrite.

References[1] Terada, K. et al. 2014. Sci. Rep. 4, 5072; DOI:10.1038/srep05072 [2] Hino, Y. et al. 2014. Nuclear Physics B (Proc.
Suppl.) 253-255, 206-207. [3] Cook, S. et al. 2017. Physical Review Accelerators and Beams 20, 030101.