Development of new cosmic-ray exposure age measurements using cosmogenic nuclides

2015 Fiscal Year Final Research Report

• Project/Area Number: 23340172
• Research Category: Grant-in-Aid for Scientific Research (B)
• Allocation Type: Single-year Grants
• Section: 一般
• Research Field: Geochemistry/Astrochemistry
• Research Institution: High Energy Accelerator Research Organization
• Principal Investigator: MATSUMURA Hiroshi 大学共同利用機関法人高エネルギー加速器研究機構, 放射線科学センター, 准教授 (30328661)
• Co-Investigator(Kenkyū-buntansha): SUEKI Keisuke 筑波大学, 数理物質科学研究科, 教授 (90187609)
• Project Period (FY): 2011-04-01 – 2016-03-31
• Keywords: ミュー粒子 / 核反応 / 宇宙線年代測定 / マグネタイト

Outline of Final Research Achievements

Long-lived radionuclides are produced by cosmic rays in surficial materials on Earth, and used for determinations of cosmic-ray exposure ages and erosion rates. The purpose of this study is a development of new cosmic-ray exposure age measurements using cosmogenic nuclides.
(1) Study of fast muon induced nuclear reactions: Most of radionuclides in deep underground are produced by fast-muon-induced nuclear reactions which is not known well. In this study, by muon irradiation experiments, it was found that the mechanism of the nuclear reaction induced by a fast muon is similar to by a photon.
(2) Development of cosmic-ray exposure age measurement using cosmogenic nuclides in magnetite: Quartz is routinely used as the target minerals for these geomorphological studies. In this study, it was indicated that magnetite is also available for the cosmic-ray exposure age measurement. Then, chemical experimental procedures for magnetite samples were facilitated to be used widely.

Free Research Field

放射化学