Hawaii Anti-Neutrino Observatory

S. Dye --- 12/15/05S. Dye --- 12/15/05 Neutrino Geophysics WorkshopNeutrino Geophysics Workshop 11

Hawaii Anti-Neutrino Hawaii Anti-Neutrino ObservatoryObservatory

For the Hanohano collaboration:For the Hanohano collaboration:

Steve DyeSteve DyeUniversity of Hawaii at ManoaUniversity of Hawaii at Manoa

andand

Hawaii Pacific UniversityHawaii Pacific University


Outline of TalkOutline of Talk

ObjectivesObjectives• 15% measurement of mantle U/Th 15% measurement of mantle U/Th

neutrinos (Qneutrinos (QU+ThU+Th= 8 ± 1 TW)= 8 ± 1 TW)

• Search for >1TW geo-reactorSearch for >1TW geo-reactor MethodsMethods

• Big “KamLAND” in the deep oceanBig “KamLAND” in the deep ocean ConclusionsConclusions


Institutions and PersonnelInstitutions and Personnel

University of Hawaii at ManoaUniversity of Hawaii at ManoaSteve Dye, Peter Grach, Gene Guillian, Steve Dye, Peter Grach, Gene Guillian,

John Learned (PI), Jelena Maricic, John Learned (PI), Jelena Maricic,

Shige Matsuno, Sandip Pakvasa, Gary Varner,Shige Matsuno, Sandip Pakvasa, Gary Varner,

Mavourneen WilcoxMavourneen Wilcox

Makai Ocean EngineeringMakai Ocean EngineeringTore Leraand, Joe Van Ryzin (PI) Tore Leraand, Joe Van Ryzin (PI)

+ Others+ Others


Funding and SupportFunding and Support

CEROSCEROS** 1-year study funds 1-year study funds• Critical issues of deep ocean deploymentCritical issues of deep ocean deployment

Implosion of PMT modulesImplosion of PMT modules Optical properties of scintillating oilOptical properties of scintillating oil Low power electronicsLow power electronics Data transmissionData transmission

• Detector design criteriaDetector design criteria Size and sensitivitySize and sensitivity

UH Physics support infrastructureUH Physics support infrastructure

* Center of Excellence for Research in Ocean Sciences* Center of Excellence for Research in Ocean Sciences


Predicted Geo-neutrino SignalPredicted Geo-neutrino Signal

F. Mantovani et al., Phys. Rev. D 69, 013001 (2004).

(1032 proton-yrs = 1 TNU ≈ 1.2 kT-y of KamLAND oil)


Geo-neutrino sourcesGeo-neutrino sources

Japan Japan

~~11::33

mantle mantle : : crust crust

Hawaii Hawaii

~~33::11

mantlemantle : : crustcrust

Plot courtesy of S. EnomotoPlot courtesy of S. Enomoto


Predicted Mantle-neutrino Predicted Mantle-neutrino Signal in Scintillating Oil Signal in Scintillating Oil

Raghavan Raghavan et al.et al. (1998) (1998)

U(ppm) = 0.01U(ppm) = 0.01

ΦΦ(U) = 7.3 TNU(U) = 7.3 TNU**

ΦΦ(Th) = 1.9 TNU(Th) = 1.9 TNU**

ΦΦ(tot) = 9.2 TNU(tot) = 9.2 TNU**

S = 7.9 per kT-yS = 7.9 per kT-y

Enomoto Enomoto thesisthesis (2005) (2005)

U(ppm) = 0.012U(ppm) = 0.012

ΦΦ(U) = 8.1 TNU(U) = 8.1 TNU

ΦΦ(Th) = 2.2 TNU(Th) = 2.2 TNU

ΦΦ(tot) = 10.3 TNU(tot) = 10.3 TNU

S = 8.8 per kT-yS = 8.8 per kT-y

S = Φ(TNU) x 0.85(kT/TNU)

* Corrected for oscillation

S = 7.9 per kT-y (Mantovani this workshop)S ~ 8.5 per kT-y (Lisi this workshop)


Geo-neutrino SignalGeo-neutrino Signal

Geo-nuanalysis

Reactor-nuanalysis


Geo-neutrino Signal plus Known Geo-neutrino Signal plus Known BackgroundsBackgrounds


Geo-neutrino Signal + Background Geo-neutrino Signal + Background with Geo-reactorwith Geo-reactor


Significance and SignalsSignificance and Signals

Signal significance: Signal significance: σσ = S / √(S+B) = S / √(S+B) Mantle-neutrino signalMantle-neutrino signal

~80 events per 10 kT-y (1.7<E~80 events per 10 kT-y (1.7<Eνν(MeV)<3.4)(MeV)<3.4)

1 TW Geo-reactor signal1 TW Geo-reactor signal38 events per 10 kT-y (3.4< E38 events per 10 kT-y (3.4< Eνν(MeV)<9.3)(MeV)<9.3)

Set Set σσ ≥ 5 for discovery (P>99.99%) ≥ 5 for discovery (P>99.99%)σσ=5 requires B<20 events per 10 kT-y=5 requires B<20 events per 10 kT-y


Geo-neutrino signature in Geo-neutrino signature in Scintillating OilScintillating Oil

p

+

Prompt signalEvis=Eν- En - 0.8 MeV

Delayed signal

Evis = 2.2MeVΔt ≈ 200µs Δr ≈ 10cm

Scintillating oil viewed with PMTs measures energy but not direction of geo-neutrino

γνe fromβ-decay onU/Th chain

Geo-neutrino


Identified BackgroundsIdentified Backgrounds

Cosmic ray muons

alpha source

Rad

ioacti

ve m

ate

rials

fast neutrons

spallationproducts

•Secondary cosmic raysFast neutronsSpallation- 9Li

•Dirty scintillating oil 13C(α,n)16O

•Impurities outsideAccidental coincidences

•AntineutrinosNuclear reactors

Earth’s crust

TargetVolume

μ±

μ±


Background ReductionBackground Reduction

Location, location, locationLocation, location, location• Far from nuclear reactors and Far from nuclear reactors and

continental crustcontinental crust• >4000 m.w.e. overburden>4000 m.w.e. overburden

Clean, clean, cleanClean, clean, clean• < 1/40 KamLAND < 1/40 KamLAND 210210Po levelPo level• Radio-pure detector materialsRadio-pure detector materials


Backgrounds: Mantle-neutrino Backgrounds: Mantle-neutrino measurementmeasurement

Scale KamLAND Scale KamLAND ((NatureNature 436436 2005) 2005)

• x 12 exposurex 12 exposure• 1/40 1/40 210210PoPo

Total expected Total expected 86±586±5

Geo-reactor adds 19 Geo-reactor adds 19 events per TW events per TW

1.7<E1.7<Eνν(MeV)<3.4(MeV)<3.4 Rate (10 kT-y)Rate (10 kT-y)-1-1

99Li (4 km)Li (4 km) 0 ± 00 ± 0

210210PoPo 13 ± 313 ± 3

AccidentalsAccidentals (<) 30 ± 1(<) 30 ± 1

Known ReactorsKnown Reactors (<) 14 ± 1(<) 14 ± 1

Crust neutrinosCrust neutrinos 29 ± 529 ± 5

TotalTotal 86 ± 586 ± 5


Backgrounds: Geo-reactor searchBackgrounds: Geo-reactor search

Scale KamLAND Scale KamLAND ((PRLPRL 9494 2005) 2005)• x 13 exposurex 13 exposure• 1/40 1/40 210210PoPo

• RRtargettarget= 5m= 5m Total expected 36±2Total expected 36±2 1.2 TW discovery 1.2 TW discovery

thresholdthreshold

3.4<E3.4<Eνν(MeV)<9.3(MeV)<9.3 Rate (10 kT-y)Rate (10 kT-y)-1-1

99Li (4 km)Li (4 km) 4 ± 14 ± 1

210210PoPo 3 ± 23 ± 2

AccidentalsAccidentals 1 ± 01 ± 0

Commercial Commercial ReactorsReactors

28 ± 128 ± 1

TotalTotal 36 ± 236 ± 2


Site SelectionSite Selection

Many sites considered- best is same as DUMAND


HanohanoHanohano


Current StatusCurrent Status

Prototype electronics fabricated and Prototype electronics fabricated and tested- tested- G. Varner, M. WilcoxG. Varner, M. Wilcox

Scintillating oil pressure tests in Scintillating oil pressure tests in preparation- preparation- P. GrachP. Grach

Implosion tests next yearImplosion tests next year Ocean demonstration of prototype Ocean demonstration of prototype

detector to followdetector to follow


Electronics prototypesElectronics prototypes

PMT base Digitizer


ConclusionsConclusions

10 kT-y exposure of Hanohano would10 kT-y exposure of Hanohano would• Measure BSE mantle U/Th to ~11%Measure BSE mantle U/Th to ~11%• Search for ~1TW geo-reactorSearch for ~1TW geo-reactor

Hanohano in design stageHanohano in design stage• 4 kT target volume “KamLAND”4 kT target volume “KamLAND”• Deep ocean deployment for few yearsDeep ocean deployment for few years

Hawaii Anti-Neutrino Observatory

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