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“ Georeactor ” Detection with Gigaton Antineutrino Detectors. Neutrinos and Arms Control Workshop February 5, 2004 Eugene Guillian University of Hawaii. Finding Hidden Nuclear Reactors. The focus of this conference is on detecting hidden man-made nuclear reactors - PowerPoint PPT Presentation
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““Georeactor” Detection with GGeoreactor” Detection with Gigaton Antineutrino Detectorsigaton Antineutrino Detectors
Neutrinos and Arms Control WorkshopNeutrinos and Arms Control Workshop
February 5, 2004February 5, 2004
Eugene GuillianEugene Guillian
University of HawaiiUniversity of Hawaii
Finding Hidden Nuclear ReactFinding Hidden Nuclear Reactorsors
The focus of this conference is on detectinThe focus of this conference is on detecting hidden man-made nuclear reactorsg hidden man-made nuclear reactors
But there may be a But there may be a natural nuclear reactnatural nuclear reactor hidden in the Earth‘s core!or hidden in the Earth‘s core!
The “Georeactor” ModelThe “Georeactor” Model
An unorthodox modelAn unorthodox model Chief proponent: Chief proponent: J.M.HerndonJ.M.Herndon
The modelThe model A fuel breeder fission reactor in the Earth‘s suA fuel breeder fission reactor in the Earth‘s su
b-coreb-core Size:Size: ~4 miles radius ~4 miles radius Power:Power: 3-10 TW 3-10 TW
Man-made vs. GeoMan-made vs. Geo
Man-made:Man-made: (~500 reactors) x (~2 GW) = (~500 reactors) x (~2 GW) = 1 TW1 TW
Georeactor:Georeactor: 3-10 TW3-10 TW
If a georeactor exists, it will be the dominant source of antineutrinos!
Outline of PresentationOutline of Presentation
1.1. Georeactor detection strategyGeoreactor detection strategy
2.2. Describe the georeactor modelDescribe the georeactor model
3.3. Can a georeactor be detected with KamLCan a georeactor be detected with KamLAND?AND?
4.4. What minimum conditions are necessary What minimum conditions are necessary to detect a georeactor?to detect a georeactor?
Strategy for Georeactor DetecStrategy for Georeactor Detectiontion
If a georeactor does If a georeactor does notnot exist… exist…
• From commercial power plants• Depends on the net power output• Rate corrected to 100% livetime & efficiency• Assume no neutrino oscillation
• Corrected to 100% livetime & efficiency• Neutrino oscillation effect included
Slope = average neutrino oscillation survival probability
<R> = Average
2f = Spread
<R> = Average
f = Spread
Rmin = (1-f)<R>
Rmax = (1+f)<R>
Y-inercept = Georeactor Rate
0
Strategy for Georeactor DetecStrategy for Georeactor Detectiontion
If a georeactor If a georeactor doesdoes exist… exist…
10 TW georeactor
Nonzero Y-intercept(0.0742 events/day @ 10 TW)
Georeactor Detection StrategGeoreactor Detection Strategyy
Plot observed rate against expected backgPlot observed rate against expected background rateround rate
Fit line through dataFit line through data Y-intercept = Y-intercept = georeactor rategeoreactor rate
The Georeactor ModelThe Georeactor Model
What we can all agree on:What we can all agree on:1.1. The Earth is made of the The Earth is made of the same stuff as metsame stuff as met
eoriteseorites
2.2. In its earliest stages, the Earth was In its earliest stages, the Earth was moltenmolten
3.3. The Earth gradually The Earth gradually cooledcooled, leaving all but t, leaving all but the outer core in solid formhe outer core in solid form
Melting a RockMelting a Rock
Very high temperature:Very high temperature: All of rock in liquid formAll of rock in liquid form
Lower temperature:Lower temperature: SlagSlag solidifies solidifies Alloys and opaque mineralsAlloys and opaque minerals still in liquid for still in liquid for
mm
Slag floatsSlag floats
Apply This Observation to the Apply This Observation to the EarthEarth
Very Hot!
All Liquid
Apply This Observation to the Apply This Observation to the EarthEarth
Cooler
Slag solidifies,Floats to surface
Fission Fuel Trapped by SlaFission Fuel Trapped by Slag?g?
Actinides (U, Th, Actinides (U, Th, etcetc.) are .) are lithophilelithophile (or ox (or oxiphile)iphile) If given a chance, they combine with slagIf given a chance, they combine with slag Slag rises to surface as the Earth coolsSlag rises to surface as the Earth cools Fission fuel found in the Earth‘s crust and maFission fuel found in the Earth‘s crust and ma
ntle, not in the corentle, not in the core Therefore, a georeactor cannot form!Therefore, a georeactor cannot form!
Fission Fuel Trapped by SlaFission Fuel Trapped by Slag?g?
Actinides (U, Th, Actinides (U, Th, etcetc.) are .) are lithophilelithophile (or ox (or oxiphile)iphile) If given a chance, they combine with slagIf given a chance, they combine with slag Slag rises to surface as the Earth coolsSlag rises to surface as the Earth cools Fission fuel found in the Earth‘s crust and maFission fuel found in the Earth‘s crust and ma
ntle, not in the corentle, not in the core Therefore, a georeactor cannot form!Therefore, a georeactor cannot form!
If there is enough oxygen
If There Were Insufficient OxyIf There Were Insufficient Oxygengen
Some of the U, Th will be in Some of the U, Th will be in alloy and sulfalloy and sulfide ide formform
These sink as the Earth coolsThese sink as the Earth cools Elements with largest atomic number shouElements with largest atomic number shou
ld sink mostld sink most Therefore, fission fuel should sink to the cTherefore, fission fuel should sink to the c
enter of the Earthenter of the Earth Georeactor can form!Georeactor can form!
How Can One Tell if the Earth How Can One Tell if the Earth Is Oxygen Poor or Not?Is Oxygen Poor or Not?
Slag has high oxygen contentSlag has high oxygen content Alloys and opaque minerals have low oxygAlloys and opaque minerals have low oxyg
en contenten content Alloy/Slag mass ratioAlloy/Slag mass ratio
Strong correlation with oxygen content in a mStrong correlation with oxygen content in a meteoriteeteorite
Oxygen Level of the EarthOxygen Level of the Earth
Oxygen Content HighLow
AlloySlag
LessSlag
MoreSlag
Meteorite Data
Ordinary Chrondite
Enstatite Chrondite
Oxygen Level of the EarthOxygen Level of the Earth
Oxygen Content HighLow
AlloySlag
LessSlag
MoreSlag
Actinidestrapped in
slag
Freeactinides
Oxygen Level of the EarthOxygen Level of the Earth
Oxygen Content HighLow
AlloySlag
LessSlag
MoreSlag
AlloySlag
CoreMantle
=
Oxygen Level of the EarthOxygen Level of the Earth
Oxygen Content HighLow
AlloySlag
LessSlag
MoreSlag
Core/Mantle ratiofrom seismic data
Measuring the Earth‘s OxidatiMeasuring the Earth‘s Oxidation Levelon Level
Equate the following:Equate the following: CoreCore alloy & opaque mineralsalloy & opaque minerals Mantle + CrustMantle + Crust silicatessilicates
Obtain Earth‘s mass ratio from density profile meObtain Earth‘s mass ratio from density profile measured with seismic dataasured with seismic data
Compare with corresponding ratio in meteorites.Compare with corresponding ratio in meteorites. Oxygen Content of the Earth:Oxygen Content of the Earth:
Same asSame as meteorite with same mass ratio as the Earthmeteorite with same mass ratio as the Earth‘s‘s
Evidence for Oxygen-poor EaEvidence for Oxygen-poor Earthrth
Herndon, J.M. (1996) Proc. Natl. Acad. Sci. USA 93, 646-648.
The EarthSeems to beOxygen-poor!
33He Evidence for GeoreactorHe Evidence for Georeactor
Fission reactors produce Fission reactors produce 33HH 33H decays to H decays to 33He (half life ~ 12 years)He (half life ~ 12 years)
33He MeasurementsHe Measurements
In air:In air: RRAA = = 33He/He/44He = 1.4 x 10He = 1.4 x 10-6-6
From deep Earth:From deep Earth: R ≈ 8 x RR ≈ 8 x RAA
Elevated deep Earth levels difficult to explElevated deep Earth levels difficult to explainain Primordial Primordial 33He and “Just-so” dilution scenariosHe and “Just-so” dilution scenarios
A georeactor naturally produces A georeactor naturally produces 33He…He…
… … and Just the Right Amount!and Just the Right Amount!
SCALE Reactor Simulator(Oak Ridge)
Deep Earth Measurement(mean and spread)
Fig. 1, J.M.Herndon,Proc. Nat. Acad. Sci.USA, Mar. 18, 2003(3047)
Other PhenomenaOther Phenomena
Georeactor as a Georeactor as a fluctuatingfluctuating energy sourc energy source for geomagnetisme for geomagnetism
3 of the 4 gas giants 3 of the 4 gas giants radiate twice as muradiate twice as much heat as they receivech heat as they receive
OkloOklo natural fission reactor (remnant) natural fission reactor (remnant)
Can a Georeactor Be DetecteCan a Georeactor Be Detected with KamLAND?d with KamLAND?
KamLANDKamLAND A 0.4 kton antineutrino detectorA 0.4 kton antineutrino detector Currently, the largest such detector in the worlCurrently, the largest such detector in the worl
dd
2-parameter fit2-parameter fit Slope (constrained)Slope (constrained) Y-intercept (unconstrained)Y-intercept (unconstrained)
Can a Georeactor Be DetecteCan a Georeactor Be Detected with KamLAND?d with KamLAND?
KamLANDKamLAND A 0.4 kton antineutrino detectorA 0.4 kton antineutrino detector Currently, the largest such detector in the worlCurrently, the largest such detector in the worl
dd
2-parameter fit2-parameter fit Slope (constrained)Slope (constrained) Y-intercept (unconstrained)Y-intercept (unconstrained)
Solar neutrinoexperiments
Can a Georeactor Be DetecteCan a Georeactor Be Detected with KamLAND?d with KamLAND?
KamLANDKamLAND A 0.4 kton antineutrino detectorA 0.4 kton antineutrino detector Currently, the largest such detector in the worlCurrently, the largest such detector in the worl
dd
2-parameter fit2-parameter fit Slope (constrained)Slope (constrained) Y-intercept (unconstrained)Y-intercept (unconstrained)
Georeactor Rate
Measuring the Georeactor RatMeasuring the Georeactor Rate with KamLANDe with KamLAND
Slope constrained by solar neutrino measurements
Slope ≈ 0.75 ± 0.15
Georeactor rate
Large BackgroundLarge Background
Background
Signal
S/B ≈ 1/3 ~ 1/8
Slope UncertaintySlope Uncertainty
1 uncertainty in solar neutrino oscillation parameters (m2, sin22)(rough estimate)
Best fit
Can a Georeactor be DetecteCan a Georeactor be Detected?d?
Use Use Error EllipseError Ellipse to answer this question to answer this question
Ellipse EquationEllipse Equation
Ellipse EquationEllipse Equation
Measured georeactore rate
(y-intercept)
True georeactore rate
Distance of measuredrate from true value
Ellipse EquationEllipse Equation
Mueasured slope Best estimate of slope(from solar experiments)
Distance of measuredslope from best estimate
Ellipse EquationEllipse Equation
Correlation between slopeand rate measurements
Ellipse EquationEllipse EquationConfidence level
of fit result
Ellipse EquationEllipse Equation
Ellipse Parameters
They determine the size of the ellipse
Ellipse EquationEllipse Equation
Ellipse Parameters
RRgg Georeactor rateGeoreactor rate
TT Exposure timeExposure time
<R><R> Average background rateAverage background rate
ff Spread in background rateSpread in background rate
mm Slope uncertaintySlope uncertainty
Parametersdepend on
Ellipse ParametersEllipse Parameters<R> = average background rate f = fractional spread of background rate T = Exposure time Rg = georeactor ratem = oscillation probability uncertainty m0 = 0.75
Error Ellipse for KamLAND, Error Ellipse for KamLAND, 3 Years3 Years
<R> ≈ 0.62 events/day<R> ≈ 0.62 events/day f ≈ 16% f ≈ 16% ((i.e.i.e. RMS(R)/<R> = 0.16) RMS(R)/<R> = 0.16)
T = 3 years T = 3 years (12% down time fraction not included)(12% down time fraction not included)
RRgg = 0.0742 events/day = 0.0742 events/day (10 TW georeactor)(10 TW georeactor)
mm = 0.15 = 0.15 (slope uncertainty from solar (slope uncertainty from solar meas.) meas.)
mm00 = 0.75 = 0.75 (slope = avg. surv. prob.)(slope = avg. surv. prob.)
KamLAND, 3 YearsKamLAND, 3 Years
KamLAND, How Many Years?KamLAND, How Many Years?
40 years for90% confidence level!
Effect of Background SpreadEffect of Background Spread
Reducing the Background LeReducing the Background Levelvel
Slope Uncertainty ImprovemeSlope Uncertainty Improvementsnts
Detector SizeDetector Size
1 Gigaton = 2,500,000
Gigaton Detector
Go ~ 2.5 km along axis!
Gigaton Detector
Summary of ResultsSummary of Results
Georeactor will Georeactor will NOTNOT be observed with Ka be observed with KamLANDmLAND
Large spread in background rate helpsLarge spread in background rate helps Low background levelLow background level
Georeactor detectable with small detectorGeoreactor detectable with small detector
Summary of ResultsSummary of Results
Slope uncertaintySlope uncertainty Improved knowledge helps somewhatImproved knowledge helps somewhat
A ~10A ~1022 increase in detector size allows ge increase in detector size allows georeactor detectionoreactor detection
1 Gigaton = 2.5 million x KamLAND1 Gigaton = 2.5 million x KamLAND
Most antineutrinos detected by a gigaton detector will be from the georeactor!
Event Rate @ Gigaton DetectEvent Rate @ Gigaton Detectoror
0.0742 events/day0.0742 events/day 0.4 kton0.4 kton 10 TW10 TW x 2,500,000
≈ 200,000 events/day
Expected rate from man-made reactors: 20,000 ev/day
CaveatCaveat
In this analysis, information from the antinIn this analysis, information from the antineutrino energy spectrum was not used.eutrino energy spectrum was not used.
Therefore the statement that KamLAND cTherefore the statement that KamLAND cannot say anything meaningful about a geannot say anything meaningful about a georeactor is prematureoreactor is premature Setting 90% limit may be possibleSetting 90% limit may be possible Positive identification, however, Positive identification, however, isis impossiblimpossibl
ee
ConclusionConclusion
An array of gigaton detectors whose primaAn array of gigaton detectors whose primary aim is arms control ry aim is arms control will definitely allow will definitely allow the detection of a georeactorthe detection of a georeactor (if it exists) (if it exists)
The detection of a georeactor will have giaThe detection of a georeactor will have giant repercussions on our understanding of nt repercussions on our understanding of planet formation and geophysicsplanet formation and geophysics
Evidence for Oxygen-poor EaEvidence for Oxygen-poor Earth (2)rth (2)
If we accept that the Earth was made from If we accept that the Earth was made from molten meteorites, the following mass ratiomolten meteorites, the following mass ratios must holds must hold
Mass(core) Mass(alloys, opaque minerals) =Mass(mantle) Mass(slag)
Using density profile from seismic data
Meteorite data
Evidence for Oxygen-poor EaEvidence for Oxygen-poor Earth (3)rth (3)
Herndon, J.M. (1996) Proc. Natl. Acad. Sci. USA 93, 646-648.
The EarthSeems to beOxygen-poor!
Earth‘s Interior from Earth‘s Interior from Two ModelsTwo Models
33He/He/44He from the Georeactor ModelHe from the Georeactor Model
SCALE Reactor Simulator(Oak Ridge)
Deep Earth Measurement(mean and spread)
Fig. 1, J.M.Herndon,Proc. Nat. Acad. Sci.USA, Mar. 18, 2003(3047)
Detection StrategyDetection Strategy
Background (commercial nuclear reactors)
Signal (georeactor)
Slope = average oscillation survival probability
Detection StrategyDetection Strategy
Slope constrained by solar neutrino measurements
Slope ≈ 0.75 ± 0.15
Georeactor rate
Slope UncertaintySlope Uncertainty
1 uncertainty in solar neutrino oscillation parameters (m2, sin22)(rough estimate)
Best fit
Slope UncertaintySlope Uncertainty
Measuring the Georeactor PoMeasuring the Georeactor Powerwer
Fit a line through data: Fit a line through data: observed vs. expected rateobserved vs. expected rate
xi = expected e rateyi = observed e ratei = stat. err. yi
i = bin index
b = georeactor ratem = commercial reactor e avg. survival probabilitym0 = best estimate from solar experimentsm = estimated uncertainty
Measuring the Georeactor PoMeasuring the Georeactor Powerwer
Fit a line through data: Fit a line through data: observed vs. expected rateobserved vs. expected rate
xi = expected e rateyi = observed e ratei = stat. err. yi
i = bin index
b = georeactor ratem = commercial reactor ne avg. survival probabilitym0 = best estimate from solar n experimentsm = estimated uncertainty
Measure this
Line Fit to DataLine Fit to Data
What Conditions are Necessary tWhat Conditions are Necessary to Detect a 10 TW Georeactor? o Detect a 10 TW Georeactor?
Detector sizeDetector size Signal and background scale by the same factorSignal and background scale by the same factor
Exposure timeExposure time Overall increase in statisticsOverall increase in statistics
Slope (average survival probability)Slope (average survival probability) Uncertainty that is independent of exposure timeUncertainty that is independent of exposure time Improvement over time with more/better solar Improvement over time with more/better solar meas meas
urementsurements Commercial reactor backgroundCommercial reactor background Spread in background levelSpread in background level
Error Contour FormulaError Contour Formula
Error Contour FormulaError Contour Formula<R> = average background rate f = fractional spread of background rate T = Exposure time Rg = georeactor ratem = oscillation probability uncertainty m0 = 0.75
KamLAND, 3 YearsKamLAND, 3 Years
KamLAND, How Many Years?KamLAND, How Many Years?
Summary of ResultsSummary of Results
Improved knowledge of neutrino oscillation Improved knowledge of neutrino oscillation parameters help, but not enough to allow parameters help, but not enough to allow KamLAND to detect a georeactorKamLAND to detect a georeactor
A x100 increase in detector size will allA x100 increase in detector size will allow 99% detection of a 10TW georeactoow 99% detection of a 10TW georeactor, even under high background conditior, even under high background conditions as in KamLANDns as in KamLAND Don‘t need to go all the way to a gigaton (x20Don‘t need to go all the way to a gigaton (x20
00), although it will allow a comfortable margi00), although it will allow a comfortable marginn