CSEDI Collaborative Research: Neutrino Geophysics: collaboration between geology and particle physics

University Of Colorado At Boulder, Boulder CO

Investigators

Abstract

The Earth's interior radiates approximately 46 terawatts (TW, 1012 J s-1) of heat (total combined production of nuclear power today is about 1 TW of energy). The Earth's thermal energy comes from the cooling of the planet, minor contributions from tidal friction and inner core growth, and significantly from the decay of radioactive elements. The exact proportional contribution of these heat supplies is unknown. Plate tectonics is the primary manifestation of heat transport within the Earth today. Large tectonic plates are produced at mid-ocean ridges and transported across the surface of the globe to deep ocean trenches, where they plunge into the Earth's interior sending cold slabs into the interior and cooling the planet. In order to better understand the dynamic processes that occur both within the solid Earth as well as on the planet's surface, we must develop a comprehensive model of Earth composition and structure that is internally consistent with observations from the fields of geology, geochemistry, geophysics and particle physics. The abundance and distribution of naturally-occurring radioactive elements is integral to the understanding of Earth dynamics, as radiogenic heat provides a key source of energy that serves to drive mantle convection, plate tectonics and the evolution of the entire planet. The primary objectives of the proposed research are to: (1) understand the nature and three-dimensional distribution of naturally-occurring radioactive elements in the Earth, particularly potassium, thorium and uranium, which produce >99% of all radiogenic heat in the Earth; (2) develop an internally consistent model of the Earth, including the thermal constitution and evolution of the planet; and, (3) build Earth models that can be tested against data from newly developed antineutrino detectors. (Antineutrinos are neutral nuclear particles produce during beta-decay of radioactive elements.) The proposed work plan involves dynamic modeling to determine the geometry, distribution and chemical composition of the Earth's major reservoirs, namely the continental crust, mantle and metallic core. Model results will be interpreted in conjunction with antineutrino data in order to develop a comprehensive, three-dimensional model of Earth composition and structure.