17:15 〜 19:15
[SIT21-P01] Development of Ocean Bottom Detector for Direct Measurement of Mantle Geoneutrinos: Simulation studies and Prototype Development
キーワード：radiogenic heat, geoneutrinos, mantle, oceanic crust
Total heat flow at the surface of the Earth from its interior is estimated to be about 47 TW. It comes from two sources – primordial and radiogenic. Radiogenic heat is primarily generated by decays of heat producing elements (HPE) 40K, 232Th, 238U, 235U and about 0.5% from 87Rb and 147Sm. Geoneutrinos, electron anti-neutrinos produced in beta minus decays of U, Th are a powerful tool to measure the radiogenic heat of the Earth. Because they interact weakly with matter, they travel undisturbed from their point of origin to the surface, carrying valuable information about the Earth's interior. Measuring the geoneutrino flux provides insights into the contribution of radiogenic heat to the total heat budget of our planet, abundance and distribution of U, Th in Earth.
The first experimental observation of geoneutrinos was reported in 2005 by the KamLAND (KL) detector and subsequent observations were made by Borexino (BX). Data from these experiments estimate the radiogenic heat flow to be about 20 TW, in agreement with the geochemical models of the composition of the Earth. The two land based detectors, soon to be joined by a third one – SNO+ and later by the fourth one – JUNO, employ geological models to disentangle the crustal and mantle contributions in the total geoneutrino flux.
However, due to inaccessibility of mantle the current geological model estimates of radiogenic power from mantle varies by an order of magnitude. Experimental observations from KL and BX lack in statistical significance because almost 70% of geoneutrino signals comes from their local lithosphere - continental crust where the distribution of HPE is highly heterogenous. This makes it challenging to isolate the contribution of radiogenic heat from mantle and takes us to the point of needing a detector far away from the continental crust. Thus, we propose to deploy a neutrino detector on the ocean floor because the crust beneath the oceans is much thinner than at the continents, allowing greater sensitivity to mantle geoneutrinos. Simulations show that such a detector placed in a strategically chosen location in the ocean will detect about 70% of geoneutrino signals from the mantle, thus making experimental advancements in the field of neutrino geophysics.
In this talk I will present the simulation studies of the proposed Ocean Bottom Detector, focusing on the expected geoneutrino spectrum and background, as well as the development of a prototype to assess the feasibility of large-scale deployment and demonstrate the advanced technologies that will be incorporated in the large size detector.
The first experimental observation of geoneutrinos was reported in 2005 by the KamLAND (KL) detector and subsequent observations were made by Borexino (BX). Data from these experiments estimate the radiogenic heat flow to be about 20 TW, in agreement with the geochemical models of the composition of the Earth. The two land based detectors, soon to be joined by a third one – SNO+ and later by the fourth one – JUNO, employ geological models to disentangle the crustal and mantle contributions in the total geoneutrino flux.
However, due to inaccessibility of mantle the current geological model estimates of radiogenic power from mantle varies by an order of magnitude. Experimental observations from KL and BX lack in statistical significance because almost 70% of geoneutrino signals comes from their local lithosphere - continental crust where the distribution of HPE is highly heterogenous. This makes it challenging to isolate the contribution of radiogenic heat from mantle and takes us to the point of needing a detector far away from the continental crust. Thus, we propose to deploy a neutrino detector on the ocean floor because the crust beneath the oceans is much thinner than at the continents, allowing greater sensitivity to mantle geoneutrinos. Simulations show that such a detector placed in a strategically chosen location in the ocean will detect about 70% of geoneutrino signals from the mantle, thus making experimental advancements in the field of neutrino geophysics.
In this talk I will present the simulation studies of the proposed Ocean Bottom Detector, focusing on the expected geoneutrino spectrum and background, as well as the development of a prototype to assess the feasibility of large-scale deployment and demonstrate the advanced technologies that will be incorporated in the large size detector.