DOCSLIB.ORG

100208 Mcdonough Ext

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
100208 Mcdonough Ext PERSPECTIVES GEOPHYSICS Neutrinos created by nuclear decay may allow geoscientists to measure the distribution of Mapping the Earth’s Engine radioactive elements in the Earth. William F. McDonough article physicists and geophysicists optimal location for measuring the rarely meet to compare notes, but ear- Continental crust (>50%) distribution of heat-producing ele- lier this year researchers from these two Proposed Mantle (<50%) ments in the ancient core of a P geoneutrino disciplines gathered to discuss antineutrinos continent. Here, the antineutrino detectors (the antiparticle of the neutrino) (1). These signal will be dominated by the fundamental particles are a by-product of crustal component at about the reactions occurring in nuclear reactors and 80% level. This experiment will pass easily through Earth, but they are also SNO+ provide data on the bulk composi- generated deep inside Earth by the natural tion of the continents and place radioactive decay of uranium, thorium, and Core (~0%) limits on competing models of the potassium (in which case they are called continental crust’s composition. geoneutrinos). Particle physicists have re- The Boron Solar Neutrino experi- cently shown that it is possible to detect Hanohano ment (Borexino) detector, situated geoneutrinos and thus establish limits on the in central Italy (and hence some- amount of radioactive energy produced in the what removed from the regions of interior of our planet (2). This year’s joint France with many reactors), has meeting was aimed at enhancing communica- begun counting (5). This detector tion between the two disciplines in order to will accumulate a geoneutrino sig- on August 31, 2007 better constrain the distribution of Earth’s nal from a younger continental radioactive elements. Inside story. One model of the distribution of radioactive ele- region and surrounding Medi- Researchers from the Kamioka Liquid ments potassium, thorium, and uranium in Earth. New antineu- terranean ocean basin, thus receiv- scintillator Anti-Neutrino Detector (Kam- trino detectors in Canada (SNO+) and Hawaii (HANOHANO) ing a greater proportion of its sig- LAND) in Japan reported results that are con- should allow more precise determination of these distributions. nal from the mantle. sistent with the power output produced from Particle physicists from Hawaii the decay of thorium and uranium (16 TW), the reactor signal overwhelmed the geoneu- and their colleagues from elsewhere in the and the abundances of these elements in trino signal. New detectors are being devel- United States, Japan, and Europe are propos- Earth, as estimated by geoscientists (3). oped, deployed, and positioned in locations ing a 10,000-ton, portable geoneutrino detec- www.sciencemag.org (Potassium geoneutrinos cannot be detected at that have substantially smaller contributions tor that is deployable on the sea floor. This present due to the high background in this from nuclear reactors, and thus will provide detector, called Hawaii Antineutrino Ob- region of the spectrum.) The initial measure- more precise measurements of neutrinos and servatory (HANOHANO, which is also Ha- ment is also broadly consistent with the Th/U antineutrinos to both the Earth science and waiian for “magnificent”), would allow the ratio for Earth being equal to that of chondritic astrophysical communities. measurement of the geoneutrino signal com- meteorites, which is a fundamental assump- In addition to detecting geoneutrinos, these ing almost exclusively from deep within tion used by geochemists to model planetary facilities are designed to detect neutrinos from Earth, far removed from the continents and Downloaded from compositions. However, the upper power limit supernovae and determine their oscillation nuclear reactors (6). Thanks to the capability determined by the experiment (60 TW at the properties (like antineutrinos, neutrinos can of multiple deployments, this detector would 3σ limit) exceeds Earth’s surface heat flow by oscillate among their three different states). As provide the exciting possibility of obtaining a factor of 1.5 and is thus not very useful as a particle physicists continue to count geoneutri- signals from different positions on the globe. constraint for the models. nos, the signal-to-noise ratio will improve Ultimately, these different detectors will Nevertheless, there is great excitement and, with more counts, the uncertainty in the allow Earth scientists to test various models within the two communities, as advances in radioactive energy budget of Earth will shrink for the vertical and lateral distribution of tho- antineutrino detection are anticipated. The and the measured Th/U ratio of the planet will rium and uranium in Earth and will yield KamLAND detector was intentionally sited be determined to a greater precision. Mea- unparalleled constraints on the composition of near nuclear reactors in order to characterize surement uncertainties of 10% or better the continents and the deeper Earth. Insights antineutrino oscillation parameters (the reac- are possible with the new detectors, and are from geoneutrinos will also allow us to decide tor produces so-called electron antineutrinos, achievable with only 4 years of counting. among competing models of Earth’s interior. and antineutrinos can oscillate between the What does this mean for the Earth sci- Decades of research on the state of mantle three different “flavors”—the electron, muon, ences? Geoneutrino detectors will be sited on convection have assumed wide-ranging and tau antineutrinos)—and sense fluctua- continental crust of different ages, including values of the Urey ratio, the proportion of tions in reactor power output. Consequently, ancient cratons, the oldest pieces of continents radioactive energy output to the total energy (see the figure). One proposal is to convert the output of the planet. Geochemists have Sudbury Neutrino Observatory (SNO) to deduced a Urey ratio of ~0.4, whereas geo- The author is in the Department of Geology, University of Maryland, College Park, MD 20742, USA. E-mail: “SNO+” (4). This 1000-ton detector is sited in physicists prefer constructing mantle convec- [email protected] a mine in Ontario, Canada, and represents an tion models assuming higher Urey ratios that www.sciencemag.org SCIENCE VOL 317 31 AUGUST 2007 1177 Published by AAAS PERSPECTIVES range up to 1.0 (7). In addition, geoneutrino composed of high-density metal, has a References 1. Deep Ocean Anti-Neutrino Observatory Workshop, data, coupled with local heat-flow data, will markedly higher electron density than the sili- Honolulu, Hawaii, 23 to 25 March 2007, be used to evaluate models of bulk continental cate shells of Earth. Likewise, there is a www.phys.hawaii.edu/~sdye/hano.html. crustal composition. Competing models differ marked contrast in electron density for the 2. T. Araki et al., Nature 436, 499 (2005). 3. W. F. McDonough, in The Mantle and Core, R. W. Carlson, by almost a factor of 2 in their concentrations inner and outer core. Measurement of neu- Ed. (Elsevier-Pergamon, Oxford, 2003), vol. 2, pp. of potassium, thorium, and uranium, with trino dispersion in these layers would substan- 547–568. some models critically dependent on heat- tially improve our knowledge of the absolute 4. M. J. Chen, Earth Moon Planets 99, 221 (2006). 5. M. G. Giammarchi, L. Miramonti, Earth Moon Planets 99, flow data (8). radius of the core and hence the precision of 207 (2006). Beyond determining the amount and dis- global seismological models. Such beam 6. J. G. Learned, S. T. Dye, S. Pakvasa, in Proceedings of the tribution of heat-producing elements in Earth, studies could also place limits on the amount XII International Workshop on Neutrino Telescopes, M. Baldo-Ceolin, Ed. (Istituto Veneto di Scienze, Lettere ed particle physicists at the workshop described of hydrogen in the core. Arti Padora, 2007), pp. 235–269. future experiments, only a decade or so away The range of novel experiments underway 7. T. Lyubetskaya, J. Korenaga J. Geophys. Res. 112, from implementation, that would allow more and those just over the horizon will directly B03212 (2007). 8. R. L. Rudnick, S. Gao, in The Crust, R. L. Rudnick, Ed. precise determination of Earth’s structure. interrogate the interior of Earth in exciting and (Elsevier-Pergamon, Oxford, 2003), vol. 3, pp. 1–64. Dispersion of neutrino beams penetrating unparalleled ways (9); these tools will essen- 9. N. H. Sleep, Earth Moon Planets 99, 343 (2006). Earth are a function of the electron density of tially provide new ways of “journeying” to the different layers of the planet. The Earth’s core, center of the Earth. 10.1126/science.1144405 ENGINEERING New technologies are being developed to protect the privacy of individuals in today’s Privacy By Design information society. George Duncan on August 31, 2007 nformation privacy used to come by advocates strengthening the powers of the default, mainly because of the high costs U.K. Information Commissioner to include Iimposed on any snooper. Yet today, tech- substantial penalties for misuse of data. nology has lowered the costs of gathering There are many important reasons to use information about individuals, linking per- personal information. For example, under sonal details, storing the information, and Megan’s Law, Web sites permit the public to broadcasting the results. Inexpensive net- locate and identify convicted sex offenders worked surveillance cameras capture our digi- in the United States. Depersonalized data on www.sciencemag.org tal image across time and place. Terabyte patient drug use can be mined to better target RAID (redundant array of independent disks) marketing efforts for pharmaceuticals; this drives provide cheap storage. Real-time data approach is used, for example, by Verispan (6). integration software turns fragmented per- Web-based social networks like Jaiku or Twitter sonal data into composite pictures of individu- facilitate peer-to-peer exchange of personal als (1). Communication that is universal, details. Road tolls can be debited electronically instantaneous, unlimited in capacity, and free from a driver’s personal account while monitor- Downloaded from for all (2) is becoming ever more plausible.
Load more

Recommended publications
  • Updated Geoneutrino Measurement with Borexino
    UPDATED GEONEUTRINO MEASUREMENT WITH BOREXINO LIVIA LUDHOVA FOR BOREXINO COLLABORATION IKP-2, FORSCHUNGSZENTRUM JÜLICH AND RWTH AACHEN UNIVERSITY, GERMANY SEPTEMBER 10TH, 2019 TAUP 2019, TOYAMA, JAPAN OUTLINE (OR WHERE IS THIS ENERGY COMING FROM?) • What are geoneutrinos and why to study them • Expected geoneutrino signal at LNGS (Italy) • Borexino and antineutrino detection • Borexino geoneutrino measurement: fresh new results • Geological interpretation EARTH’S HEAT BUDGET Radiogenic heat & Integrated surface heat flux: Geoneutrinos can help! Htot = 47 + 2 TW Lithosphere Mantle Heat production in lithosphere “well” known Big uncertainty Mantle cooling 7 - 9 TW Heat production in mantle 1 – 27 TW 4 – 27 TW Core cooling 9 – 17 TW Core cooling Mantle cooling Geoneutrinos: antineutrinos/neutrinos from the decays of long-lived radioactive isotopes naturally present in the Earth 238U (99.2739% of natural U) à 206Pb + 8 α + 8 e- + 6 anti-neutrinos + 51.7 MeV 232Th à 208Pb + 6 α + 4 e- + 4 anti-neutrinos + 42.8 MeV 235U (0.7205% of natural U) à 207Pb + 7 α + 4 e- + 4 anti-neutrinos + 46.4 MeV 40K (0.012% of natural K) à 40Ca + e- + 1 anti-neutrino + 1.32 MeV (BR=89.3 %) 40K + e- à 40Ar + 1 neutrino + 1.505 MeV (BR=10.7 %) q the only direct probe of the deep Earth q released heat and geoneutrino flux in a well fixed ratio q to measure geoneutrino flux = (in principle) = to get radiogenic heat q in practice (as always) more complicated….. Earth shines in geoneutrinos: flux ~106 cm-2 s-1 leaving freely and instantaneously the Earth interior (to
    [Show full text]
  • Review Article Geoneutrinos
    Hindawi Publishing Corporation Advances in High Energy Physics Volume 2012, Article ID 235686, 34 pages doi:10.1155/2012/235686 Review Article Geoneutrinos Ondrejˇ Srˇ amek,´ 1 William F. McDonough,1 and John G. Learned2 1 Department of Geology, University of Maryland, College Park, MD 20742, USA 2 Department of Physics and Astronomy, University of Hawaii, Honolulu, HI 96822, USA Correspondence should be addressed to Ondrejˇ Srˇ amek,´ [email protected] Received 9 July 2012; Accepted 20 October 2012 Academic Editor: Arthur B. McDonald Copyright q 2012 Ondrejˇ Srˇ amek´ et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. Neutrino geophysics is an emerging interdisciplinary field with the potential to map the abundances and distribution of radiogenic heat sources in the continental crust and deep Earth. To date, data from two different experiments quantify the amount of Th and U in the Earth and begin to put constraints on radiogenic power in the Earth available for driving mantle convection and plate tectonics. New improved detectors are under construction or in planning stages. Critical testing of compositional models of the Earth requires integrating geoneutrino and geological observations. Such tests will lead to significant constraints on the absolute and relative abundances of U and Th in the continents. High radioactivity in continental crust puts limits on land-based observatories’ capacity to resolve mantle models with current detection methods. Multiple-site measurement in oceanic areas away from continental crust and nuclear reactors offers the best potential to extract mantle information.
    [Show full text]
  • Experimental Aspects of Geoneutrino Detection: Status and Perspectives
    Experimental Aspects of Geoneutrino Detection: Status and Perspectives O. Smirnov,1 1JINR, Joint Institute for Nuclear Research, Dubna, Russian Federation October 22, 2019 Abstract Neutrino geophysics, the study of the Earth's interior by measuring the fluxes of geologically produced neutrino at its surface, is a new interdisciplinary field of science, rapidly developing as a synergy between geology, geophysics and particle physics. Geoneutrinos, antineutrinos from long- lived natural isotopes responsible for the radiogenic heat flux, provide valuable information for the chemical composition models of the Earth. The calculations of the expected geoneutrino signal are discussed, together with experimental aspects of geoneutrino detection, including the description of possible backgrounds and methods for their suppression. At present, only two detectors, Borexino and KamLAND, have reached sensitivity to the geoneutrino. The experiments accumulated a set of ∼190 geoneutrino events and continue the data acquisition. The detailed description of the experiments, their results on geoneutrino detection, and impact on geophysics are presented. The start of operation of other detectors sensitive to geoneutrinos is planned for the near future: the SNO+ detector is being filled with liquid scintillator, and the biggest ever 20 kt JUNO detector is under construction. A review of the physics potential of these experiments with respect to the geoneutrino studies, along with other proposals, is presented. New ideas and methods for geoneutrino detection are reviewed. Contents 1 Introduction 2 2 Geoneutrinos and the Earth's heat 4 2.1 Long-lived radiogenic elements . 4 2.2 Radiogenic heat and geoneutrino luminosity of the Earth . 9 arXiv:1910.09321v1 [physics.geo-ph] 21 Oct 2019 3 Geoneutrino flux calculation 11 3.1 Neutrino oscillations .
    [Show full text]
  • Neutrino Oscillations: the Rise of the PMNS Paradigm Arxiv:1710.00715
    Neutrino oscillations: the rise of the PMNS paradigm C. Giganti1, S. Lavignac2, M. Zito3 1 LPNHE, CNRS/IN2P3, UPMC, Universit´eParis Diderot, Paris 75252, France 2Institut de Physique Th´eorique,Universit´eParis Saclay, CNRS, CEA, Gif-sur-Yvette, France∗ 3IRFU/SPP, CEA, Universit´eParis-Saclay, F-91191 Gif-sur-Yvette, France November 17, 2017 Abstract Since the discovery of neutrino oscillations, the experimental progress in the last two decades has been very fast, with the precision measurements of the neutrino squared-mass differences and of the mixing angles, including the last unknown mixing angle θ13. Today a very large set of oscillation results obtained with a variety of experimental config- urations and techniques can be interpreted in the framework of three active massive neutrinos, whose mass and flavour eigenstates are related by a 3 3 unitary mixing matrix, the Pontecorvo- × Maki-Nakagawa-Sakata (PMNS) matrix, parameterized by three mixing angles θ12, θ23, θ13 and a CP-violating phase δCP. The additional parameters governing neutrino oscillations are the squared- mass differences ∆m2 = m2 m2, where m is the mass of the ith neutrino mass eigenstate. This ji j − i i review covers the rise of the PMNS three-neutrino mixing paradigm and the current status of the experimental determination of its parameters. The next years will continue to see a rich program of experimental endeavour coming to fruition and addressing the three missing pieces of the puzzle, namely the determination of the octant and precise value of the mixing angle θ23, the unveiling of the neutrino mass ordering (whether m1 < m2 < m3 or m3 < m1 < m2) and the measurement of the CP-violating phase δCP.
    [Show full text]
  • Exploring the Earth's Mantle with Geoneutrinos
    IL NUOVO CIMENTO Vol. 36 C, N. 1 Gennaio-Febbraio 2013 DOI 10.1393/ncc/i2013-11446-1 Colloquia: IFAE 2012 Exploring the Earth’s mantle with geoneutrinos ∗ G. Fiorentini(1)(2)(3),G.L.Fogli(4)(5),E.Lisi(5), F. Mantovani(1)(3)( ), A. M. Rotunno(4)andG. Xhixha(2) (1) Dipartimento di Fisica, Universit`a di Ferrara - Via Saragat 1, 44100 Ferrara, Italy (2) INFN, Laboratori Nazionali di Legnaro - Via dell’Universit`a 2 - 35020 Legnaro (PD), Italy (3) INFN, Sezione di Ferrara - Via Saragat 1, 44100 Ferrara, Italy (4) Dipartimento Interateneo di Fisica “Michelangelo Merlin” Via Amendola 173, 70126 Bari, Italy (5) INFN, Sezione di Bari - Via Orabona 4, 70126, Bari, Italy ricevuto il 31 Agosto 2012 Summary. — The KamLAND and Borexino experiments have observed, each at ∼ 4σ level, signals of electron antineutrinos produced in the decay chains of thorium and uranium in the Earth’s crust and mantle (Th and U geoneutrinos). Various pieces of geochemical and geophysical information allow an estimation of the crustal geoneutrino flux components with relatively small uncertainties. The mantle component may then be inferred by subtracting the estimated crustal flux from the measured total flux. On the base of this approach we find that crust- subtracted signals show hints of a residual mantle component, emerging at ∼ 2.4σ level by combining the KamLAND and Borexino data. The inferred mantle flux slightly favors scenarios with relatively high Th and U abundances, within ±1σ uncertainties comparable to the spread of predictions from recent mantle models. PACS 95.55.Vj – Neutrino, muon, pion, and other elementary particle detectors; cosmic ray detectors.
    [Show full text]
  • 40K Geoneutrino Detection
    40K Geoneutrino Detection Mark Chen Queen’s University and the Canadian Institute for Advanced Research Neutrino Geoscience 2015, Paris, France June 15, 2015 Why Potassium Geoneutrinos? n ~16% of Earth’s radiogenic heat is from 40K q would be good to quantify after 238U and 232Th n K/U ratio in chondrites > in the crust q would measurement help pin down abundances of other moderate volatiles in the Earth? n K may reside in the Earth’s core?? q e.g. Murthy, Lee and Jeanloz, Ohtani q does this help solve some core energetics issues (e.g. geodynamo, heat flow at CMB)? Th & U Volatility trend @ 1AU from Sun slide from Bill McDonough 40K Decay 40K→40Ca + e− +ν n 89.28% Qβ=1.311 MeV e 40 − 40 n 10.72% QEC=1.505 MeV K + e → Ar +ν e q 10.67% to 1.461 MeV state (Eν = 44 keV) q 0.05% to g.s. (Eν = 1.5 MeV) 0.0117% isotopic abundance 40K Spectrum + threshold for ν e + p → e + n [figure from KamLAND Nature paper] Potassium Geoneutrino Fluxes n (5-15) × 106 cm−2 s−1 for the antineutrinos 5 −2 −1 n (5-15) × 10 cm s for the 44 keV νe 3 −2 −1 n (2-6) × 10 cm s for the 1.5 MeV νe n compare to 1.44 MeV pep solar νe 8 −2 −1 1.42 × 10 cm s (and also CNO solar neutrinos at 1.5 MeV) You can probably forget about detecting the –5 1.5 MeV νe … only 63 keV away and 10 less intense! 40 K ν e Detection n ν e -e scattering q requires electron recoil directionality due to large flux of solar neutrinos (could imagine giant TPC) n 1/3 event per ton per year n NC nuclear excitation q not distinctive from νe or γ nuclear excitation n NC coherent neutrino-nucleus scattering
    [Show full text]
  • Expected Geoneutrino Signal at JUNO
    Expected geoneutrino signal at JUNO Virginia STRATI1,2,*, Marica BALDONCINI1,3, Ivan CALLEGARI2, Fabio MANTOVANI1,3, William F. McDONOUGH4, Barbara RICCI1,3, Gerti XHIXHA2 1 Department of Physics and Earth Sciences, University of Ferrara, Via Saragat 1, 44121 - Ferrara, Italy 2 INFN, Legnaro National Laboratories, Viale dell’Università, 2 - 35020 Legnaro (Padua) Italy 3 INFN, Ferrara Section, Via Saragat 1, 44121 - Ferrara, Italy 4 Department of Geology, University of Maryland, 237 Regents Drive, College Park, MD 20742, USA. *Corresponding author Email: [email protected] Abstract Constraints on the Earth’s composition and on its radiogenic energy budget come from the detection of geoneutrinos. The KamLAND and Borexino experiments recently reported the geoneutrino flux, which reflects the amount and distribution of U and Th inside the Earth. The JUNO neutrino experiment, designed as a 20 kton liquid scintillator detector, will be built in an underground laboratory in South China about 53 km from the Yangjiang and Taishan nuclear power plants, each one having a planned thermal power of approximately 18 GW. Given the large detector mass and the intense reactor antineutrino flux, JUNO aims to collect high statistics antineutrino signals from reactors but also to address the challenge of discriminating the geoneutrino signal from the reactor background. 6.5 The predicted geoneutrino signal at JUNO is 39.75.2 TNU, based on the existing reference Earth model, with the dominant source of uncertainty coming from the modeling of the compositional variability in the local upper crust that surrounds (out to ~500 km) the detector. A special focus is dedicated to the 6° × 4° Local Crust surrounding the detector which is estimated to contribute for the 44% of the signal.
    [Show full text]
  • Partial Radiogenic Heat Model for Earth Revealed by Geoneutrino Measurements
    ARTICLES PUBLISHED ONLINE: 17 JULY 2011 | DOI: 10.1038/NGEO1205 Partial radiogenic heat model for Earth revealed by geoneutrino measurements The KamLAND Collaboration* The Earth has cooled since its formation, yet the decay of radiogenic isotopes, and in particular uranium, thorium and potassium, in the planet’s interior provides a continuing heat source. The current total heat flux from the Earth to space is 44:2 ± 1:0 TW, but the relative contributions from residual primordial heat and radiogenic decay remain uncertain. However, radiogenic decay can be estimated from the flux of geoneutrinos, electrically neutral particles that are emitted during radioactive decay and can pass through the Earth virtually unaffected. Here we combine precise measurements of the geoneutrino flux from the Kamioka Liquid-Scintillator Antineutrino Detector, Japan, with existing measurements from the C8:8 Borexino detector, Italy. We find that decay of uranium-238 and thorium-232 together contribute 20:0−8:6 TW to Earth’s heat flux. The neutrinos emitted from the decay of potassium-40 are below the limits of detection in our experiments, but are known to contribute 4 TW. Taken together, our observations indicate that heat from radioactive decay contributes about half of Earth’s total heat flux. We therefore conclude that Earth’s primordial heat supply has not yet been exhausted. he Kamioka Liquid-Scintillator Antineutrino Detector mantle, outer core and inner core. Although the mechanical (KamLAND) Collaboration reported the results of the first properties and bulk composition of the shells are well established, Tstudy of electron antineutrinos (νe s) produced within the their detailed composition, including the abundances of radiogenic Earth in 2005 (ref.
    [Show full text]
  • Updated Geoneutrino Measurement with the Borexino Detector
    Updated Geoneutrino Measurement with the Borexino Detector Aktualisierte Geoneutrino-Messung mit dem Borexino-Detektor von Sindhujha Kumaran Master arbeit in Physik vorgelegt der Fakultat¨ fur¨ Mathematik, Informatik und Naturwissenschaften der RWTH AACHEN September 2018 angefertigt im Physikalischen Institut III. B Erstgutachter und Betreuer Zweitgutachter Prof. Dr. Livia Ludhova Prof. Dr. Achim Stahl Physikalischen Institut III. B Physikalischen Institut III. B RWTH Aachen RWTH Aachen Ich versichere, dass ich die Arbeit selbstst¨andigverfasst und keine anderen als die angegebenen Quellen und Hilfsmittel benutzt sowie Zitate kenntlich gemacht habe. Aachen, den To my dearest brother, Aswin. \That you are here|that life exists and identity, That the powerful play goes on, and you may contribute a verse." -O Me! O Life!, Walt Whitman Abstract Geoneutrinos are electron antineutrinos and neutrinos emitted in the radioactive decays from the Earth's interior. Due to the intrinsic dependence of the geoneutrino flux and the heat produced in the radioactive decays, geoneutrinos contribute uniquely to our knowledge about the Earth. The main goal of neutrino geophysics is to use the obtained geoneutrino signals in estimating the abundance and distribution of the heat producing elements such as 238U, 235U, 232Th and 40K. The radiogenic heat contribution, especially the mantle contribution to the total surface heat flux and the nature of the mantle still remain as open questions. The combination of the total geoneu- trino flux (≈106 cm−2s−1) and the weak interaction cross section (≈10−42 cm−2s−1) lead to huge statistical uncertainties in the current measurements. This has made the study of geoneutrinos quite challenging and so far, only two detectors, namely KamLAND and Borexino, have measured geoneutrinos.
    [Show full text]
  • Geoneutrinos and the Heat Budget of the Earth
    Geoneutrinos and the heat budget of the Earth Ondřej Šrámek University of Maryland presented at Department of Geophysics, Charles University in Prague on 14 November 2012 Collaboration with Bill McDonough (UMD), Steve Dye (HPU), Shijie Zhong (UCB), Edwin Kite (Caltech), Vedran Lekić (UMD) Seismology Geodynamics Mineral physics Experimental Geochemistry particle physics ......... Geoneutrinos “Geoneutrinos” = electron anti-neutrinos emitted in β− decays of naturally occurring radionuclides geo-ν’s now detectable ... and have been detected Measuring radioactivity of the Earth! How much radiogenic heating in the mantle?? What is the Earth made of?? Chemical reservoirs in the mantle?? 1. geophysical motivation 2. neutrino history 3. antineutrino production, propagation, detection 4. observations of geoneutrinos 5. predictions of geoneutrinos flux 6. perspectives Radiogenic heating rate in the mantle...? How do we know it...? heat output (surface heat flux) 238U primordial heat + 232 radiogenic heating Th 40K ? How much radiogenic heating in the Earth? How is it spatially distributed? ... implications for geodynamics U Th K Composition of Silicate Earth • U, Th, K are lithophile elements, strong arguments against presence in the core • Composition of “Silicate Earth” (BSE) of interest, Silicate Earth = whole Earth minus the core • [But: some unorthodox models even predicting natural nuclear reactor in Earth’s deep interior] • Cosmochemistry and geochemistry: BSE compositional estimates • Difficult. Usual problem in geophysics: rock samples only
    [Show full text]
  • Editorial Neutrino Masses and Oscillations
    Hindawi Publishing Corporation Advances in High Energy Physics Volume 2014, Article ID 823127, 4 pages http://dx.doi.org/10.1155/2014/823127 Editorial Neutrino Masses and Oscillations Elisa Bernardini,1 Leslie Camilleri,2 Vincenzo Flaminio,3 Srubabati Goswami,4 and Seon-Hee Seo5 1 DESY, Platanen Allee 6, 15738 Zeuthen, Germany 2 Columbia University 435 W. 116th Street, New York, NY 10027-7201, USA 3 Physics Department and INFN, Largo Bruno Pontecorvo, 56127 Pisa, Italy 4 Physical Research Laboratory, Navrangpura, Ahmedabad 380009, India 5 Department of Physics and Astronomy, Seoul National University, Republic of Korea Correspondence should be addressed to Vincenzo Flaminio; [email protected] Received 17 December 2013; Accepted 17 December 2013; Published 30 March 2014 Copyright © 2014 Elisa Bernardini et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. The publication of this article was funded by SCOAP3. The year 2013 marks the 100th anniversary of the birth of originated a vast number of both experimental and theoreti- Bruno Pontecorvo, who first suggested the possibility that cal developments. neutrinos might have a nonzero mass such that oscillations The original ideas (1957-58) are first considered in this among different neutrino states might occur. Pontecorvo paper. This is followed by the consideration of a later paper constantly pursued this idea, after the discovery of other by Pontecorvo on neutrino oscillations (1967) and by the neutrino flavours, until his death. anticipation of the solar neutrino problem.
    [Show full text]
  • GEONEUTRINO RADIOMETRIC ANALYSIS for GEOSCIENCES (GRAFG) at DUSEL HOMESTAKE, SOUTH DAKOTA White Paper Update to DEDC, June 30, 2008
    GEONEUTRINO RADIOMETRIC ANALYSIS FOR GEOSCIENCES (GRAFG) AT DUSEL HOMESTAKE, SOUTH DAKOTA White Paper Update To DEDC, June 30, 2008 by P. ILA, W. GOSNOLD, G. I. LYKKEN, P. JAGAM Abstract Neutrino detection is a mature area of research, which is rapidly developing in the area of particle physics to improve detection sensitivities and optimization for specific applications. Large-scale detectors (meaning kilo-ton or more in size) were designed and built to study particle physics properties and solar neutrinos. Recently a 1-ton detector was optimized for detecting the antineutrinos from a power reactor. Directionality in the detection of the neutrinos was exploited in Cerenkov detectors. In this context it was realized the 1-ton detector is competitive and mobile for certain applications in geosciences. The cost of building large detectors is in the range of few hundred millions dollars. The 1-ton detector can be built for under10 million dollars. A fully tested and used detector may be available for immediate research and development purposes in geosciences. Our goal is to develop a radiometric method using antineutrinos from the Earth for in-situ determination of the heat producing elements (HPE) in regions inaccessible to conventional sampling techniques. We also want to investigate correlations with HPE in different geothermal regions. Page 1 of 21 INTERESTED PRINCIPALS, COLLABORATORS AND OTHERS Working Group Members: • Group Leader and Low Radioactivity Measurement of HPE: Dr. P. Ila, Earth, Atmospheric and Planetary Sciences Dept., Massachusetts Institute of Technology, Cambridge, MA • Heat Flow/Geophysics: Prof. W. Gosnold, Geology and Geological Engineering Dept., Grand Forks, University of North Dakota, ND • Cosmic-ray Physics: Prof.
    [Show full text]