Muon Radiography in Exploration Geophysics

PreviousNext No AccessProceedings of the 13th SEGJ International Symposium, Tokyo, Japan, 12–14 November 2018Muon radiography in Exploration GeophysicsAuthors: Taro KusagayaKunihiro MorishimaKouji NaritaKeiichi SuzukiToshiyuki NakanoMitsuhiro NakamuraTaro KusagayaKawasaki Geological Engineering Co., Ltd.Search for more papers by this author, Kunihiro MorishimaNagoya UniversitySearch for more papers by this author, Kouji NaritaScience Impact Inc.Search for more papers by this author, Keiichi SuzukiKawasaki Geological Engineering Co., Ltd.Search for more papers by this author, Toshiyuki NakanoNagoya UniversitySearch for more papers by this author, and Mitsuhiro NakamuraNagoya UniversitySearch for more papers by this authorhttps://doi.org/10.1190/SEGJ2018-005.1 SectionsAboutPDF/ePub ToolsAdd to favoritesDownload CitationsTrack CitationsPermissions ShareFacebookTwitterLinked InRedditEmail Abstract In the recent decade, a nondestructive investigation method, muon radiography, has been developing and applied to volcanoes, pyramids, blast furnaces, World Heritage, etc. With this technique, we can measure the density distribution inside the target object by cosmic-ray muons. Measured cosmic-raymuon intensities can be converted to density-related information. To measure cosmic-ray muons, for example, there are methods using scintillators or nuclear emulsions (high-sensitive photographic films). When using scintillators, we detect scintillation lights generated inside a scintillator by a high photo-sensitive sensor. On the other hand, when using nuclear emulsions, we get the picture of three dimensionally aligned silver grains inside the emulsion by a microscope. The film method has benefits such as availability without electricity, high spatial resolution, and high angle resolution. In this paper, we introduce the detailed cosmic-ray-muon measurement method by nuclear emulsion films. A nuclear emulsion is composed of a plastic basement sandwiched by emulsions containing silver halide compound. Their thicknesses are several hundred micrometers and dozens of micrometers, respectively. It is made inside a darkroom and vacuum-sealed not to expose to air and light. Since exposing to cosmic rays begins right after making, several nuclear emulsions are stacked just before the beginning of measurement and shifted just after the end of measurement. Thus, we can distinguish the trajectories recorded during the measurement period and the ones recorded in other periods. After developing nuclear emulsion, the exposed silver grains are read by a microscope and straight trajectories are recognized as cosmic-ray muons. These muon trajectories are integrated into each arrival direction, and thus we obtain the angle distribution of cosmic-ray muons. Finally, we show the difference of obtained density distribution inside a target object with different-angle-resolution measurements by synthetic calculation. Keywords: muon, cosmic ray, radiography nuclear emulsion, scintillator, densityPermalink: https://doi.org/10.1190/SEGJ2018-005.1FiguresReferencesRelatedDetails Proceedings of the 13th SEGJ International Symposium, Tokyo, Japan, 12–14 November 2018ISSN (online):2159-6832Copyright: 2019 Pages: 588 publication data© 2018 Published in electronic format with permission by the Society of Exploration Geophysicists of JapanPublisher:Society of Exploration GeophysicistsSociety of Exploration Geophysicists of Japan HistoryPublished Online: 29 Apr 2019 CITATION INFORMATION Taro Kusagaya, Kunihiro Morishima, Kouji Narita, Keiichi Suzuki, Toshiyuki Nakano, and Mitsuhiro Nakamura, (2019), "Muon radiography in Exploration Geophysics," SEG Global Meeting Abstracts : 15-18. https://doi.org/10.1190/SEGJ2018-005.1 Plain-Language Summary Keywordsmuoncosmic rayradiography nuclear emulsionscintillatordensityPDF DownloadLoading ...