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Hawaii Anti-Neutrino Observatory

Hawaii Anti-Neutrino Observatory. For the Hanohano collaboration: Steve Dye University of Hawaii at Manoa and Hawaii Pacific University. Outline of Talk. Objectives 15% measurement of mantle U/Th neutrinos (Q U+Th = 8 ± 1 TW) Search for >1TW geo-reactor Methods

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Hawaii Anti-Neutrino Observatory

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

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

  3. Institutions and Personnel • 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 Tore Leraand, Joe Van Ryzin (PI) • + Others Neutrino Geophysics Workshop

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

  5. Predicted Geo-neutrino Signal (1032 proton-yrs = 1 TNU ≈ 1.2 kT-y of KamLAND oil) F. Mantovani et al., Phys. Rev. D 69, 013001 (2004). Neutrino Geophysics Workshop

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

  7. 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) = 0.012 Φ(U) = 8.1 TNU Φ(Th) = 2.2 TNU Φ(tot) = 10.3 TNU S = 8.8 per kT-y Predicted Mantle-neutrino Signal in Scintillating Oil S = Φ(TNU) x 0.85(kT/TNU) S = 7.9 per kT-y (Mantovani this workshop) S ~ 8.5 per kT-y (Lisi this workshop) * Corrected for oscillation Neutrino Geophysics Workshop

  8. Geo-neutrino Signal Geo-nu analysis Reactor-nu analysis Neutrino Geophysics Workshop

  9. Geo-neutrino Signal plus Known Backgrounds Neutrino Geophysics Workshop

  10. Geo-neutrino Signal + Background with Geo-reactor Neutrino Geophysics Workshop

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

  12. Geo-neutrino signature in Scintillating Oil Scintillating oil viewed with PMTs measures energy but not direction of geo-neutrino p Delayed signal Evis = 2.2MeV Δt ≈ 200µs Δr ≈ 10cm + Geo-neutrino νefrom β-decay on U/Th chain γ Prompt signal Evis=Eν- En - 0.8 MeV Neutrino Geophysics Workshop

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

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

  15. Backgrounds: Mantle-neutrino measurement • Scale KamLAND (Nature436 2005) • x 12 exposure • 1/40 210Po • Total expected 86±5 • Geo-reactor adds 19 events per TW Neutrino Geophysics Workshop

  16. Backgrounds: Geo-reactor search • Scale KamLAND (PRL94 2005) • x 13 exposure • 1/40 210Po • Rtarget= 5m • Total expected 36±2 • 1.2 TW discovery threshold Neutrino Geophysics Workshop

  17. Site Selection Many sites considered- best is same as DUMAND Neutrino Geophysics Workshop

  18. Hanohano Neutrino Geophysics Workshop

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

  20. Electronics prototypes PMT base Digitizer Neutrino Geophysics Workshop

  21. Conclusions • 10 kT-y exposure of Hanohano would • Measure BSE mantle U/Th to ~11% • Search for ~1TW geo-reactor • Hanohano in design stage • 4 kT target volume “KamLAND” • Deep ocean deployment for few years Neutrino Geophysics Workshop

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