S. Dye /15/05 Neutrino Geophysics Workshop 1 Hawaii Anti-Neutrino Observatory For the Hanohano collaboration: Steve Dye University of Hawaii at Manoa and Hawaii Pacific University

S. Dye /15/05 Neutrino Geophysics Workshop 2 Outline of Talk Objectives Objectives 15% measurement of mantle U/Th neutrinos (Q U+Th = 8 ± 1 TW)15% measurement of mantle U/Th neutrinos (Q U+Th = 8 ± 1 TW) Search for >1TW geo-reactorSearch for >1TW geo-reactor Methods Methods Big “KamLAND” in the deep oceanBig “KamLAND” in the deep ocean Conclusions Conclusions

S. Dye /15/05 Neutrino Geophysics Workshop 3 Institutions and Personnel University of Hawaii at Manoa University of Hawaii at Manoa Steve Dye, Peter Grach, Gene Guillian, John Learned (PI), Jelena Maricic, Shige Matsuno, Sandip Pakvasa, Gary Varner, Mavourneen Wilcox Makai Ocean Engineering Makai Ocean Engineering Tore Leraand, Joe Van Ryzin (PI) + Others + Others

S. Dye /15/05 Neutrino Geophysics Workshop 4 Funding and Support CEROS * 1-year study funds CEROS * 1-year study funds Critical issues of deep ocean deploymentCritical issues of deep ocean deployment Implosion of PMT modules Implosion of PMT modules Optical properties of scintillating oil Optical properties of scintillating oil Low power electronics Low power electronics Data transmission Data transmission Detector design criteriaDetector design criteria Size and sensitivity Size and sensitivity UH Physics support infrastructure UH Physics support infrastructure * Center of Excellence for Research in Ocean Sciences

S. Dye /15/05 Neutrino Geophysics Workshop 5 Predicted Geo-neutrino Signal F. Mantovani et al., Phys. Rev. D 69, (2004). (10 32 proton-yrs = 1 TNU ≈ 1.2 kT-y of KamLAND oil)

S. Dye /15/05 Neutrino Geophysics Workshop 6 Geo-neutrino sources Japan Japan ~1:3 ~1:3 mantle : crust Hawaii Hawaii ~3:1 ~3:1 mantle : crust Plot courtesy of S. Enomoto

S. Dye /15/05 Neutrino Geophysics Workshop 7 Predicted Mantle-neutrino Signal in Scintillating Oil Raghavan et al. (1998) U(ppm) = 0.01 Φ(U) = 7.3 TNU * Φ(Th) = 1.9 TNU * Φ(tot) = 9.2 TNU * S = 7.9 per kT-y Enomoto thesis (2005) U(ppm) = Φ(U) = 8.1 TNU Φ(Th) = 2.2 TNU Φ(tot) = 10.3 TNU S = 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)

S. Dye /15/05 Neutrino Geophysics Workshop 8 Geo-neutrino Signal Geo-nu analysis Reactor-nu analysis

S. Dye /15/05 Neutrino Geophysics Workshop 9 Geo-neutrino Signal plus Known Backgrounds

S. Dye /15/05 Neutrino Geophysics Workshop 10 Geo-neutrino Signal + Background with Geo-reactor

S. Dye /15/05 Neutrino Geophysics Workshop 11 Significance and Signals Signal significance: σ = S / √(S+B) Signal significance: σ = S / √(S+B) Mantle-neutrino signal Mantle-neutrino signal ~80 events per 10 kT-y (1.7<E ν (MeV)<3.4) 1 TW Geo-reactor signal 1 TW Geo-reactor signal 38 events per 10 kT-y (3.4< E ν (MeV)<9.3) Set σ ≥ 5 for discovery (P>99.99%) Set σ ≥ 5 for discovery (P>99.99%) σ=5 requires B<20 events per 10 kT-y

S. Dye /15/05 Neutrino Geophysics Workshop 12 Geo-neutrino signature in Scintillating Oil p + Prompt signal E vis =E ν - E n MeV Delayed signal E vis = 2.2MeV Δt ≈ 200µs Δr ≈ 10cm Scintillating oil viewed with PMTs measures energy but not direction of geo-neutrino γ ν e from β-decay on U/Th chain Geo-neutrino

S. Dye /15/05 Neutrino Geophysics Workshop 13 Identified Backgrounds Cosmic ray muons alpha source Radioactive materials fast neutrons spallation products Secondary cosmic rays Fast neutrons Spallation- 9 Li Dirty scintillating oil 13 C(α,n) 16 O Impurities outside Accidental coincidences Antineutrinos Nuclear reactors Earth’s crust Target Volume μ±μ± μ±μ±

S. Dye /15/05 Neutrino Geophysics Workshop 14 Background Reduction Location, location, location Location, location, location Far from nuclear reactors and continental crustFar from nuclear reactors and continental crust >4000 m.w.e. overburden>4000 m.w.e. overburden Clean, clean, clean Clean, clean, clean < 1/40 KamLAND 210 Po level< 1/40 KamLAND 210 Po level Radio-pure detector materialsRadio-pure detector materials

S. Dye /15/05 Neutrino Geophysics Workshop 15 Backgrounds: Mantle-neutrino measurement Scale KamLAND Scale KamLAND (Nature ) x 12 exposurex 12 exposure 1/ Po1/ Po Total expected 86±5 Total expected 86±5 Geo-reactor adds 19 events per TW Geo-reactor adds 19 events per TW 1.7<E ν (MeV)<3.4 Rate (10 kT-y) -1 9 Li (4 km) 0 ± Po 13 ± 3 Accidentals (<) 30 ± 1 Known Reactors (<) 14 ± 1 Crust neutrinos 29 ± 5 Total 86 ± 5

S. Dye /15/05 Neutrino Geophysics Workshop 16 Backgrounds: Geo-reactor search Scale KamLAND (PRL ) Scale KamLAND (PRL ) x 13 exposurex 13 exposure 1/ Po1/ Po R target = 5mR target = 5m Total expected 36±2 Total expected 36±2 1.2 TW discovery threshold 1.2 TW discovery threshold 3.4<E ν (MeV)<9.3 Rate (10 kT-y) -1 9 Li (4 km) 4 ± Po 3 ± 2 Accidentals 1 ± 0 Commercial Reactors 28 ± 1 Total 36 ± 2

S. Dye /15/05 Neutrino Geophysics Workshop 17 Site Selection Many sites considered- best is same as DUMAND

S. Dye /15/05 Neutrino Geophysics Workshop 18 Hanohano

S. Dye /15/05 Neutrino Geophysics Workshop 19 Current Status Prototype electronics fabricated and tested- G. Varner, M. Wilcox Prototype electronics fabricated and tested- G. Varner, M. Wilcox Scintillating oil pressure tests in preparation- P. Grach Scintillating oil pressure tests in preparation- P. Grach Implosion tests next year Implosion tests next year Ocean demonstration of prototype detector to follow Ocean demonstration of prototype detector to follow

S. Dye /15/05 Neutrino Geophysics Workshop 20 Electronics prototypes PMT baseDigitizer

S. Dye /15/05 Neutrino Geophysics Workshop 21 Conclusions 10 kT-y exposure of Hanohano would 10 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 stage Hanohano in design stage 4 kT target volume “KamLAND”4 kT target volume “KamLAND” Deep ocean deployment for few yearsDeep ocean deployment for few years