Non-destructive elemental analysis of a carbonaceous chondrite with direct current Muon beam at MuSIC

K Terada,Y Kawashima,A Sato,S Tachibana,K Ninomiya,G Yoshida,Y Kawai,T Osawa,K Shimomura

doi:10.1038/s41598-017-15719-5

Abstract

Electron- or X-ray-induced characteristic X-ray analysis has been widely used to determine chemical compositions of materials in vast research fields. In recent years, analysis of characteristic X-rays from muonic atoms, in which a muon is captured, has attracted attention because both a muon beam and a muon-induced characteristic X-ray have high transmission abilities. Here we report the first non-destructive elemental analysis of a carbonaceous chondrite using one of the world-leading intense direct current muon beam source (MuSIC; MUon Science Innovative Channel). We successfully detected characteristic 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. Because of its high sensitivity to carbon, non-destructive elemental analysis with a muon beam can be a novel powerful tool to characterize future retuned samples from carbonaceous asteroids.

Highlights

The muon is one of the charged leptons, and has a mass of 105.7 MeV/c2, approximately 200 times heavier than the electron
A 3 cm × 3 cm × 0.6 cm chip of Jbilet Winselwan meteorite was prepared for the bulk elemental analysis at the MuSIC facility (Fig. 1)
The meteorite chip was exposed to the muon beam with the momentum of 60 MeV/c for about 20 hours, and a muonic X-ray spectrum emitting out from the ~3-mm depth of the sample was obtained with a high-purity germanium detector

Summary

Introduction

The muon is one of the charged leptons, and has a mass of 105.7 MeV/c2, approximately 200 times heavier than the electron. Electron-induced Kα–X-rays of C, O, Si, and Fe that are used for energy-dispersive X-ray spectroscopy (EDS) on scanning electron microscopes (SEM) and/or electron microprobes (EPMA) have energies of 0.3, 0.5, 1.7, and 6.4 keV, respectively, whereas muonic Kα–X-rays of C, O, Si, and Fe have energies of 75, 134, 400, and 1256 keV, respectively Such high-energy characteristic muonic X-rays can pass through the 1cm-size material without significant absorption. In November 2009, J-PARC MUSE (Japan Proton Accelerator Research Complex, MUon Science Establishment) succeeded in providing a decay muon rate of 106 muons/s for a momentum of 60 MeV/c, which has been the most intense “pulsed” muon beam in the world (25 Hz packet of muon cloud5) This intense pulsed muon beam has been used for various novel applications, one of which is non-destructive chemical analysis. Osawa et al. reported further technical development for the elemental analysis at J-PARC MUSE

Methods

Results

Conclusion