Observation of anti-neutrinos emitted from radioactive isotopes inside the Earth(geo-neutrinos) bring direct information on the Earth’s chemical composition and its heat balance, which strongly relate to the Earth’s dynamics.
To date, two experiments (KamLAND and Borexino) have measured geo-neutrinos and constrained the range of acceptable models for the Earth’s composition, but distinguishing the mantle flux by land-based detectors is challenging as the crust signal is about 70 % of the total anti-neutrino flux.
Given the oceanic crust is thinner than continental crust and has lower concentration of radioactive elements, geo-neutrino detector in the ocean, Ocean Bottom Detector (OBD), makes it sensitive to geo-neutrinos originating from the Earth’s mantle. Another unique feature of OBD is keeping the distance from the reactors which are the main background sources for land-based detectors. In addition, this movable detector can observe at multiple points in the ocean.
Our working group was jointly constructed from interdisciplinary communities in Japan which include particle physics, geoscience, and ocean engineering. We have started to work on technological developments of OBD.
In this presentation, I present the status of development and future plan.