Transcript Neutrino Geophysics

Neutrino Geophysics in Hawaii
Presentation by Steve Dye
Associate Professor of Physics
Hawaii Pacific University
January 20, 2005
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Outline of Presentation
 Neutrinos
 Geophysics
 Neutrino
Geophysics
 HANOHANO
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Neutrinos
Discovery
 Place in nature
 Properties
 Detection

– Astrophysics
– Nuclear reactors
http://www.flyingneutrinos.com
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Discovery of Neutrino
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W. Pauli proposes
undetected particle
in β-decay (1931)
E. Fermi develops
theory of β-decay
with “little neutral
one” (1934)
C. Cowan and F.
Reines detect
neutrinos at nuclear
reactors (1950's)
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http://www.ps.uci.edu/physics/reinesphotos.html
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Neutrino’s Place in Nature
http://www.particleadventure.org/particleadventure/frameless/chart.html
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Neutrino Properties
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Come in three
flavours
– e, μ, τ
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No electric charge
Stable
Weak interactions
Massive (slightly)
Flavour oscillations
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Neutrino Detection
http://www.ps.uci.edu/physics/reinesphotos.html
http://www-sk.icrr.u-tokyo.ac.jp/doc/sk/photo/normal.html
http://www-personal.umich.edu/~jcv/IMBdiverbig.jpg
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Neutrino Astrophysics

Neutrinos are excellent astrophysical
probes
– Stable, uncharged, weakly-interacting

Low energy (eV scale)
– Detection of “Big Bang” neutrinos difficult

Medium energy (MeV scale)
– Detection of stellar neutrinos established

High energy (TeV to EeV scale)
– Detection of extragalactic neutrinos
progressing
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Neutrino AstrophysicsSN1987a
http://www-personal.umich.edu/~jcv/imb/imbp5.html
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http://elvis.phys.lsu.edu/svoboda/superk/cossun.pdf
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http://elvis.phys.lsu.edu/svoboda/superk/sun.gif
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Neutrinos from Nuclear Reactors
http://www.insc.anl.gov/pwrmaps/map/world_map.php
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Underground Neutrino Detector
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KamLAND in Japan
– 1000 tonnes of
liquid scintillator
– ~2000 PMTs
– Rate in 400 tonnes
~1/(2 days) from
reactors at 180 km
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Anti-Neutrino Detection
from John G. Learned “Monitoring All Earth Reactors”
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Neutrinos in Japan


KamLand signal
primarily neutrinos
from nuclear
reactors
Neutrinos from
Earth detected!
Raghavan hep-ex/0208038
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Summary Point #1
Neutrinos exist with measured
properties
 Neutrinos carry information from
deep inside stars, galaxies, and Earth
 Neutrinos of energy ~1 MeV can be
detected using proven techniques

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Geophysics
http://www.solarviews.com/cap/earth/earthfg2.htm
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Seismology

Earthquake waves
– Pressure waves
• P (primary) waves
– Shear waves
• S (secondary) waves
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Solids
– Transmit P and S
waves
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Fluids
– Transmit only P
waves
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http://www.mantleplumes.org/Energetics.html
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Earth’s Interior
http://mantleplumes.org/Energetics.html
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Geodynamo
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Magnetic field
– Dipole
– Convection in outer core
– Rotation of Earth
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Magnetic field
required for life to
exist
– Deflects radiation
– Helps retain
atmosphere
http://www.es.ucsc.edu/~glatz/geodynamo/html
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Global Heat Flow
http://www.geo.lsa.umich.edu/IHFC/heatflow.html
>24,000 field measurements
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http://www.geo.lsa.umich.edu/IHFC/heatflow.html
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Earth Radioactivity
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Long-lived radioactive isotopes
Decay of heavy elements heats the Earth
How much heat and from where are the main
questions
U/Th/K distribution in the core, mantle, crust
http://neutrino2004.in2p3.fr/slides/monday/fiorentini.pdf
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Summary Point #2
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Much to be learned in geophysics
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–
–
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Composition of mantle and core
Origin of Earth
Source of heat flow
Mechanism of geodynamo
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Geo-neutrinos
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Anti-neutrinos
from the Earth
Arise from decay
of radioactive
elements (U+Th+K)
in crust, mantle,
and maybe core
Detection above 1.8
MeV proven (U+Th)
Domogatsky et al., hep-ph/0409069
Rothschild, Chen and Calaprice: nucl-ex/9710001
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Geo-neutrinos
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Contributions from
continental crust,
oceanic crust, and
mantle
Possible
observational sites
–
–
–
–
–
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Japan
Italy
Canada
Russia
Curacao
Hawaii
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Geo-neutrinos at Curacao
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Dutch project
– Long, narrow
underground shafts
– Instrumented with
nuclear detectors
– Strives to measure
neutrino direction

Goal: Neutrino
tomography of Earth
R.J. de Meijer EARTH Info-001
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Anti-Neutrinos from the Core
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J. Marvin Herndon
Breeder (fission) reactor
deep within inner core
Explains heat flow,
geomagnetic field
variability, He3/He4
Power output 3-10 TW
Observable through
neutrino emission
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Geo-reactor neutrinos

Test of geo-reactor
hypothesis requires
special location for
clear signal
– Far from man-made
reactors
– Far from continental
crust

Hawaii is excellent
site
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Raghavan hep-ex/0208038
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HANOHANO
(Hawaiian for magnificent)
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Hawaii Anti-Neutrino Observatory
New initiative in Hawaii for neutrino geophysics project
Objectives are:
– Measure geo-neutrinos from mantle and U/Th
– Test geo-reactor hypothesis
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Method:
– Deploy KamLAND-like detector in the deep (4-5 km) ocean
near Hawaii and operate for about 1 year
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Funding:
– Submitting proposal to CEROS next week for design study
– If successful, propose CEROS follow-on for prototype testing
– Next go for order of $100M from NSF for full detector
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Deep Ocean Technology
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Hawaii-2 Observatory
– Deployed in 1998
– Another off Japan ’93
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Neutrino detector
possible in 3-5 years
http://oceanusmag.whoi.edu/images/v42n2-chave1en.jpg
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Summary and Conclusion
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Neutrino detection is a viable (only?) method
for learning what is inside Earth
Various neutrino geophysics projects being
considered around the globe
Hawaii is an excellent site for a project
Deep ocean technology sufficiently advanced
HANOHANO
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