1 / 31

Geoneutrinos: applications, future directions and defining the Earth’s engine

Geoneutrinos: applications, future directions and defining the Earth’s engine. Bill McDonough , * Yu Huang + Ondřej Šrámek and Roberta Rudnick Geology, U Maryland Steve Dye , Natural Science, Hawaii Pacific U and Physics, U Hawaii Shijie Zhong , Physics, U Colorado

dorjan
Download Presentation

Geoneutrinos: applications, future directions and defining the Earth’s engine

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Geoneutrinos: applications, future directions and defining the Earth’s engine Bill McDonough, *Yu Huang +OndřejŠrámek and Roberta Rudnick Geology, U Maryland Steve Dye, Natural Science, Hawaii Pacific U and Physics, U Hawaii ShijieZhong, Physics, U Colorado Fabio Mantovani, Physics, U Ferrara, Italy *graduate student +post-doc

  2. Update on Earth Models: …views from the last year! Murakami et al (May - 2012, Nature): “…the lower mantle is enriched in silicon … consistent with the [CI] chondritic Earth model.” Campbell and O’Neill (March - 2012, Nature): “Evidence against a chondritic Earth” Zhang et al (March - 2012, Nature Geoscience): The Ti isotopic composition of the Earth and Moon overlaps that of enstatite chondrites. Fitoussi and Bourdon (March - 2012, Science): “Si isotopes support the conclusion that Earth was not built solely from enstatite chondrites.” Warren (Nov - 2011, EPSL): “Among known chondrite groups, EH yields a relatively close fit to the stable-isotopic composition of Earth.” - Compositional models differ widely, implying a factor of three difference in the U & Th content of the Earth

  3. Nature & amount of Earth’s thermal power radiogenic heating vs secular cooling - abundance of heat producing elements (K, Th, U) in the Earth - clues to planet formation processes - amount of radiogenic power to drive mantle convection & plate tectonics - is the mantle layered or does it have large deep structures? estimates of BSE from 9TW to 36TW constrains chondritic Earth models estimates of mantle 1.3TW to 28TW superplume piles, e.g., source of Hawaii the future… Geoneutrino studies

  4. Plate Tectonics, Convection, Geodynamo Radioactive decay driving the Earth’s engine!

  5. 1s Earth’s surface heat flow 46 ± 3 (47 ± 2) Mantle cooling (18 TW) Crust R* (8 ± 1 TW) (Rudnick and Gao ‘03) Core (~9 TW) - (4-15 TW) Mantle R* (12 ± 4 TW) total R* 20 ± 4 *R radiogenic heat (after McDonough & Sun ’95) (0.4 TW) Tidal dissipation Chemical differentiation after Jaupart et al 2008 Treatise of Geophysics

  6. Earth’s thermal evolution: role of K, Th & U Archean boundary Power (TW) Arevalo, McDonough, Luong (2009) EPSL

  7. U in the Earth: • ~13 ng/g U in the Earth • Metallic sphere (core) • <<1 ng/g U • Silicate sphere • 20* ng/g U • *O’Neill & Palme (2008) 10 ng/g • *Turcotte & Schubert (2002) 31 ng/g • Continental Crust • 1300 ng/g U • Mantle • ~12 ng/g U Th/U = 4, K/U ~104 (established by chondrites) Chromatographic separation Mantle melting & crust formation

  8. 2011 Detecting Geoneutrinos from the Earth 2005 2010

  9. Terrestrial Antineutrinos 238U 232Th νe+ p+→ n + e+ 1.8 MeV Energy Threshold 1α, 1β 1α, 1β 238U 232Th 40K 234Pa 228Ac 2.3 MeV 2.1 MeV 5α, 2β 4α, 2β 214Bi 212Bi νe νe νe νe 3.3 MeV 2.3 MeV 2α, 3β 1α, 1β 206Pb 40K 40Ca 208Pb Terrestrial antineutrinos from uranium and thorium are detectable 1β 1% 31% 46% 20% Efforts to detect K geonus underway

  10. Determining Th/U is a challenge

  11. Summary of geoneutrino results Constrainting U & Th in the Earth McDonough, Learned, Dye (2012) Physics Today MODELS Cosmochemical: uses meteorites – O’Neill & Palme (’08); Javoy et al (‘10); Warren (‘11) Geochemical: uses terrestrial rocks – McD & Sun ’95; Allegre et al ‘95; Palme O’Neil ‘03 Geophysical: parameterized convection – Schubert et al; Davies; Turcotte et al; Anderson

  12. Earth’s geoneutrino flux Interrogating the composition of the continental crust and “thermo-mechanical pile” (super-plumes?) in the mantle …

  13. Constructing a 3-D reference model Earth assigning chemical and physical states to Earth voxels

  14. Estimating the geoneutrino flux at SNO+ • Geology • Geophysics seismic x-section

  15. Global to Regional RRM SNO+ Sudbury Canada using only global inputs improving our flux models adding the regional geology

  16. Predicted Global geoneutrino flux based on our new Reference Model Yu Huang et al (2013) arXiv:1301.0365

  17. Models for understand Th & U in the Modern Mantle • Inputs • Bulk Sil. Earth • Cont. Crust • Depleted Mantle Geonu data Data vs Models BSE Models

  18. Structures in the mantle

  19. Testing Earth Models Šrámeket al (2013) 10.1016/j.epsl.2012.11.001; arXiv:1207.0853

  20. Predicted Global geoneutrino flux - new Reference Model Yu Huang et al (2013) arXiv:1301.0365 Predicted Mantle flux Šrámeket al (2013) 10.1016/j.epsl.2012.11.001; arXiv:1207.0853

  21. Present LS-detectors, data update? Borexino, Italy (0.6kt) KamLAND, Japan (1kt) SNO+, Canada (1kt) from 2002 to Nov 2009 +4.1 +29 106 9.9 -3.4 -28 under construction from May ‘07 to Dec ‘09 (online later this yr?)

  22. Daya Bay II China (20kt) LENA, EU (50kt) Future detectors? Hanohano International ocean-based (50kt)

  23. THE LENA DETECTOR AN OVERVIEW 100m 30m DETECTOR DIMENSIONS inner detector- 50kt of organic liquid scintillator (Ø 26m)- 13,500 photomultipliersouter muon veto- water Čerenkov detector- 2m of active shielding LOCATION - mine or deep see plateau- depth of 4,000 m.w.e. to reducem-&cosmogenic background proton decaysolar neutrinosterrestrial neutrinosatmospheric neutrinos artificial neutrino sources supernova neutrinosdiffuse SN neutrino backgroundPHYSICS GOALS

  24. Daya Bay II Geoneutrino Signal

  25. Hanohano An experiment with joint interests in Physics, Geology, and Security • multiple deployments • deep water cosmic shield • control-able L/E detection A Deep Ocean e Electron Anti-Neutrino Observatory Deployment Sketch Descent/ascent 39 min

  26. Earth’s radiogenic (Th & U) power • 20 ± 9 TW* (23 ± 10) • Prediction: models range from • 11 to 28 TW • Future: -SNO+ online 2013 • …2020…?? • Daya Bay II • LENA • Hanohano? • Neutrino Tomography… 

  27. Geoneutrinos: ongoing efforts and wish list - Directionality - 40K geonus - Detecting hidden objects down there

  28. Reconstructed event direction • Interaction kinematics • Neutron absorption • Position resolution • Scintillator properties Δθ Delayed n capture Δθ Neutron Emission Angle θn νe Neutrino direction Prompt e+ Neutron Kinetic Energy (keV) Measuring Antineutrino Direction • Terrestrial antineutrino direction • measurement shows promise- • Much to gain for geology • Further study warranted after Hiroko Watanabe’s past presentations

  29. Potassium Geo-neutrinos? • Absolute amount differs, but proportion of radiogenic heat production are similar • 40K ~19%, 232Th 42% and 238U 39% • 40K give the largest flux of geonus! • Where is the potassium in the Earth? • Continental crust has ~40%, mantle ~60% • K may reside in the Earth’s core after Mark Chen’s past presentations

  30. Detecting 40K-geoneutrinos • Using 106Cd based detectors (M. Chen, 2006) • Directional Dark Matter detectors • (Dye et al, 2013) • elastic scattering on electrons

  31. Plenty of suggestions for Geo-reactors deep inside the Earth Based on: R. de Meijer & W. van Westrenen South African Journal of Science (2008)

More Related