講演情報
[MZZ49-05]次世代地球ニュートリノ観測によるLLSVP化学組成の測定可能性評価
*許 智豪1、Simran Chauhan1、Brian C. Crow2、Max A. A. Dornfest2、Stephen T. Dye2、John Graham2、細谷 南咲1、井上 邦雄1、John G. Learned2、Viacheslav A. Li3、William McDonough4,5,6、小野 隆伸1、酒井 汰一1,7、Jackson Seligman2、Nathan Sibert2、Shang-Wen Stradleigh8、David Vartanyan9、渡辺 寛子1、Jeffrey Yepez2 (1.東北大学ニュートリノ科学研究センター、2.ハワイ大学マノア校、3.ローレンス・リバモア国立研究所、4.東北大学・海洋研究開発機構 変動海洋エコシステム高等研究所、5.マリーランド大学カレッジパーク校、6.中国科学院海洋研究所地球ニュートリノ研究センター、7.高エネルギー加速器研究機構、8.カリフォルニア大学マーセド校、9.カーネギー天文台)
キーワード：
地球ニュートリノ、マントル、放射性物質、地熱、LLSVP
Geophysical studies indicate that the Earth’s interior is highly heterogeneous, containing large-scale structures. One of the most prominent features is the Large Low Shear Velocity Provinces (LLSVPs), imaged by seismic tomography as regions with anomalously slow S-wave velocities relative to the surrounding mantle beneath the Pacific Ocean and Africa. The origin of these structures remains debated. One hypothesis suggests LLSVPs result from anomalous chemical compositions enriched in U, Th, and other elements (thermochemical piles), while an alternative hypothesis proposes they are purely thermal features without distinct chemical signatures.
Geoneutrino detection provides a promising approach to address this issue. Geoneutrinos, generated by the beta decay of radioisotopes inside the Earth, traverse the planet with little interaction and can be detected at the surface. However, previous measurements lack angular resolution, preventing the identification of specific source regions. Recent technological advances, such as gadolinium-doped liquid scintillators for enhanced neutron tagging and segmented detector designs, may enable geoneutrino observations with directional sensitivity.
In this study, we present a feasibility study on future geoneutrino detectors equipped with angular resolution. Specifically, we evaluate the sensitivity to mantle heterogeneities and the abundance of heat-producing elements within LLSVPs. Our results suggest that the optimal location for such a detector is near Hawaii, directly above the central Pacific LLSVP. This finding highlights the significant potential of the Ocean Bottom Detector (OBD) project to unravel the chemical nature of the deep Earth.
Geoneutrino detection provides a promising approach to address this issue. Geoneutrinos, generated by the beta decay of radioisotopes inside the Earth, traverse the planet with little interaction and can be detected at the surface. However, previous measurements lack angular resolution, preventing the identification of specific source regions. Recent technological advances, such as gadolinium-doped liquid scintillators for enhanced neutron tagging and segmented detector designs, may enable geoneutrino observations with directional sensitivity.
In this study, we present a feasibility study on future geoneutrino detectors equipped with angular resolution. Specifically, we evaluate the sensitivity to mantle heterogeneities and the abundance of heat-producing elements within LLSVPs. Our results suggest that the optimal location for such a detector is near Hawaii, directly above the central Pacific LLSVP. This finding highlights the significant potential of the Ocean Bottom Detector (OBD) project to unravel the chemical nature of the deep Earth.