Development of non-destructive isotopic analysis methods using muon beams and their application to the analysis of lead

Elemental isotopic ratios are measured in various research fields and provide useful information regarding age, origin, geological and biological activities, ancient climate, etc. Here, we report a new isotopic analysis method without sample destruction using muon-induced characteristic X-rays. We demonstrated this method by conducting muon-beam irradiation experiments on two Pb plates with different isotopic ratios: natural isotopic composition and artificially enriched 208Pb. The observed broad X-ray peaks of the Pb Kα line around 6 MeV were deconvolved with 206Pb, 207Pb, and 208Pb isotopes, giving the isotopic ratios. The resulting isotopic ratios were consistent with those obtained from mass spectrometry.