Fabio Mantovani Siena University & INFN Ferrara A roadmap for geo-neutrinos: A roadmap for geo-neutrinos: theory and experiment theory and experiment arXiv:0707.3203
Summary • Geo-neutrinos: a new • Geo-neutrinos: a new probe of Earth's interior probe of Earth's interior • Open questions about • Open questions about radioactivity in the Earth radioactivity in the Earth • The impact of • The impact of KamLAND KamLAND • The potential of future • The potential of future experiments experiments You are • A possible shortcut in • A possible shortcut in here the roadmap the roadmap
Geo-neutrinos: anti-neutrinos from the Earth Geo-neutrinos: anti-neutrinos from the Earth 40 K in the Earth release heat together with anti U, Th and 40 K in the Earth release heat together with anti- - U, Th and U, Th and 40 K in the Earth release heat together with anti- neutrinos, in a well fixed ratio well fixed ratio: : neutrinos, in a neutrinos, in a well fixed ratio: • Earth emits (mainly) antineutrinos • Earth emits (mainly) antineutrinos • Earth emits (mainly) antineutrinos whereas whereas whereas Sun shines in neutrinos. Sun shines in neutrinos. Sun shines in neutrinos. • A fraction of geo • • A fraction of geo-neutrinos from U and Th (not from 40 K) are neutrinos from U and Th (not from 40 40 K) are A fraction of geo- -neutrinos from U and Th (not from K) are β on protons: above threshold for inverse β + above threshold for inverse β on protons: ν + → + − on protons: above threshold for inverse p e n 1.8 MeV • Different components can be distinguished due to different • Different components can be distinguished due to different • Different components can be distinguished due to different ν with highest energy are from Uranium. - ν energy spectra: e. g. anti- ν with highest energy are from Uranium. energy spectra: e. g. anti- with highest energy are from Uranium. energy spectra: e. g. anti
Probes of the Earth’s interior Probes of the Earth’s interior • Deepest hole is about 12 km • • Deepest hole is about 12 km Deepest hole is about 12 km • Samples from the crust (and the • • Samples from the crust (and the Samples from the crust (and the upper portion of mantle) are upper portion of mantle) are upper portion of mantle) are available for geochemical analysis. available for geochemical analysis. available for geochemical analysis. • Seismology reconstructs density • • Seismology reconstructs density Seismology reconstructs density profile (not composition) throughout profile (not composition) throughout profile (not composition) throughout all Earth. all Earth. all Earth. Geo- -neutrinos: a new probe of Earth's interior neutrinos: a new probe of Earth's interior Geo Geo-neutrinos: a new probe of Earth's interior � They escape freely and instantaneously from � � They escape freely and instantaneously from They escape freely and instantaneously from Earth’s interior. Earth’s interior. Earth’s interior. � They bring to Earth’s surface information about � � They bring to Earth’s surface information about They bring to Earth’s surface information about the chemical composition of the whole planet. the chemical composition of the whole planet. the chemical composition of the whole planet.
Open questions about natural Open questions about natural radioactivity in the Earth radioactivity in the Earth 1 - - What is the What is the 1 1 - What is the 4 - - What is hidden in the What is hidden in the 4 4 - What is hidden in the radiogenic contribution radiogenic contribution radiogenic contribution Earth’s core? Earth’s core? Earth’s core? to terrestrial heat to terrestrial heat to terrestrial heat (geo- -reactor, reactor, (geo (geo-reactor, production? production? production? 40 K, …) 40 K, …) 40 K, …) 2 - - How much How much 2 2 - How much U and Th in U and Th in U and Th in the crust? the crust? the crust? 5 - - Is the standard Is the standard 5 5 - Is the standard geochemical model geochemical model geochemical model 3 - - How much U and How much U and 3 3 - How much U and (BSE BSE) consistent ) consistent ( (BSE) consistent Th in the mantle? Th in the mantle? Th in the mantle? with geo- -neutrino data? neutrino data? with geo with geo-neutrino data?
“Energetics of the Earth and the “Energetics of the Earth and the missing heat source mistery” * missing heat source mistery” * � Heat flow from the Earth is the equivalent � � Heat flow from the Earth is the equivalent Heat flow from the Earth is the equivalent of some 10000 nuclear power plants of some 10000 nuclear power plants of some 10000 nuclear power plants H Earth H Earth = ( 30 = ( 30 - - 44 )TW 44 )TW H Earth = ( 30 - 44 )TW � The BSE canonical model, based on � � The BSE canonical model, based on The BSE canonical model, based on cosmochemical arguments, predicts a cosmochemical arguments, predicts a cosmochemical arguments, predicts a radiogenic heat production ~ 19 TW: radiogenic heat production ~ 19 TW: radiogenic heat production ~ 19 TW: ? ? ~ 9 TW estimated ~ 9 TW estimated from radioactivity in the from radioactivity in the ~ 9 TW estimated from radioactivity in the (continental) crust (continental) crust (continental) crust ~ 10 TW supposed supposed from radioactivity in the from radioactivity in the ~ 10 TW ~ 10 TW supposed from radioactivity in the mantle mantle mantle 19 TW 30 – 44 TW ~ 0 TW assumed ~ 0 TW assumed from the core from the core ~ 0 TW assumed from the core radiogenic heat flow heat � Unorthodox or even heretical models have � � Unorthodox or even heretical models have Unorthodox or even heretical models have been advanced… been advanced… been advanced… * D. L. Anderson (2005),Technical Report, www.MantlePlume.org
Predictions of the Predictions of the BSE reference model BSE reference model Fiorentini et al. - JHep. 2004 Signal from U+Th Mantovani et al. Fogli et al. Enomoto et al. [TNU] (2004) (2005) (2005) Pyhasalmi 51.5 49.9 52.4 Homestake 51.3 Baksan 50.8 50.7 55.0 Sudbury 50.8 47.9 50.4 Gran Sasso 40.7 40.5 43.1 Kamioka 34.5 31.6 36.5 Curacao 32.5 Hawaii 12.5 13.4 13.4 • 1 TNU = one event per 10 32 free protons per year • 1 TNU = one event per 10 32 free protons per year • All calculations in agreement to the 10% level • All calculations in agreement to the 10% level • Different locations exhibit different contributions of radioactivity • Different locations exhibit different contributions of radioactivity from crust and from mantle from crust and from mantle
Fiorentini et al. (2005) Geo-neutrino signal Geo-neutrino signal and radiogenic heat and radiogenic heat from the Earth from the Earth region allowed by region allowed by region allowed by BSE: signal between 31 and BSE: signal between 31 and BSE: signal between 31 and 43 TNU 43 TNU 43 TNU region containing all region containing all region containing all models consistent with models consistent with models consistent with geochemical and geochemical and geochemical and geophysical data geophysical data geophysical data The graph is site dependent: The graph is site dependent: The graph is site dependent: U and Th measured in U and Th measured in U and Th measured in � the “slope” is universal � � the “slope” is universal the “slope” is universal the crust implies a signal at the crust implies a signal at the crust implies a signal at � the intercept depends on the site � � the intercept depends on the site the intercept depends on the site least of 24 TNU least of 24 TNU least of 24 TNU (crust effect) (crust effect) (crust effect) Earth energetics implies Earth energetics implies Earth energetics implies the signal does not exceed � the width depends on the site the signal does not exceed � the signal does not exceed � the width depends on the site the width depends on the site 62 TNU 62 TNU 62 TNU (crust effect) (crust effect) (crust effect)
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