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The IceCube collaboration

Hiroko Miyamoto and the IceCube collaboration are using the Earth as a filter to detect cosmic neutrinos and study their interactions. This overview discusses their findings, detector deployment, calibration, and science goals.

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The IceCube collaboration

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  1. Hiroko Miyamoto

  2. The IceCube collaboration Antarctica Hiroko Miyamoto

  3. Earth Detector cosmic ray • Look for the neutrino’s interaction product (e,m,t) • Use the earth as a filter • 1:1,000,000 background rejection! n n m HE νs come from…- SN, AGN, GRB, EHE proton…?

  4. Infrequently, a cosmic neutrino is captured in the ice, i.e. the neutrino interacts with an ice nucleus • In the crash a muon (or electron, • or tau) is produced Cherenkov light cone muon interaction Detector • The muon radiates blue light in its wake • Optical sensors capture (and map) the light neutrino Hiroko Miyamoto

  5. Recent AMANDA results • Atmospheric Neutrinos - reported 3329 atmospheric νs from the period 2000-2003. flux: E-3.7 >1TeV, Emax ~ 300 TeV. (K. Munich for the IceCube Collaboration, ICRC Pune 2005, K. Daum et al., Zeitschrift fur Physik C66 (1995) 417) • GRB search - Searched more than 500 GRBs. No observed signal. -> most stringent limits (K.Kuehn for the IceCube Collaboration, M.Stamatikos for the IceCube Collaboration, B.Hughey for the IceCube Collaboration, ICRC Pune 2005) • Neutralino Dark matter - limit for the Sun based on one year of data (2000) (M.Ackermann et al., Astropart.Phys. 24 (2006) 459) • Point source searches- 5 years of data (1001 effective days) of the AMANDA-II detector have been analyzed for a signal from neutrino point sources.... Hiroko Miyamoto

  6. AMANDA-II Skymap - Point Sources Significance / s 2000-2004 Largest fluctuation: 3.7s at 12.6 h, +4.5 deg Random events • No statistically significant source of neutrinos has been found so far. • The analysis provides the most stringent limits on neutrino fluxes from point sources on the northern hemisphere. • From the end of 2007 IceCube will improve the limits beyond the reach of AMANDA-II . Several “hotspots” are identifiable, however.... 69 out of 100 sky maps with randomized events show an excess higher than 3.7s Hiroko Miyamoto

  7. IceCube Science Goals • Steady galactic and extra-galactic neutrino sources (SNRs, AGNs, binary stars) • Variable neutrino sources (micro-quasars, magnetars) • GRBs • Exotic neutrino sources (monopoles) • GZK neutrinos Hiroko Miyamoto

  8. Detector Overview & Deployment status 2006 Hiroko Miyamoto

  9. ~1 km Digital Optical Module IceTop 1450m AMANDA 60 DOMs IceCube 2450m • 400ns/6.4ms time range • 400 photoelectron/15ns • measure individual photon arrival time • 1~2ns time resolution The IceCube Detector • Measure individual photon arrival time: • 2 ping-ponged four-channel Advanced Transient Waveform Digitizers (ATWDs): • 200-700 MHz • 128 samples (400 ns • max range) • 400 pe / 15 ns • Fast Analog-to-Digital • Converter: • 40 MHz • 6.4 s range • InIce IceCube detector • 70 strings • 60 modules each • Horizontal spacing ~ 125m • Vertical spacing ~ 17m • Depth from 1450-2450m • Sensitive to neutrinos from • few hundred GeV to • extremely high energies • 9 strings deployed • IceTop air shower array • 80 surface detector • stations • 2 frozen water tanks for each station 32 tanks deployed • AMANDA-II • 677 OMs on 19 strings • Dark Noise rate ~ 700 Hz • Local Coincidence rate ~ 15 Hz • Deadtime < 1% • Signal digitized in the ice Hiroko Miyamoto

  10. 10” PMT Hamamatsu Flasher board 10” PMT Hamatsu-70 Main board 32.5 cm IceCube Digital Optical Module Hiroko Miyamoto

  11. IceTop station 2 frozen-water tanks / station 2 DOMs / tank String Deployment Setup at South Pole Hose reel Drill tower 5 MW Hot water generator IceTop tanks Hot-water drilling • Hole size ~60cm • Depth ~2.5km • Straight to 1m Hiroko Miyamoto

  12. String Deployment Drilling to 2500 m < 40h String deployment ~ 12h Hiroko Miyamoto

  13. and more This year’s strings deep in ice Toward 70 strings - km3 detector 9 strings and 16 ice-top stations have been deployed ~125m AMANDA Hiroko Miyamoto

  14. String Installation Schedule Baseline Plan Year Annual Total 2004/05 1 1 2005/06 8 9 2006/07 12 21 2007/08 14 35 2008/09 14 49 2009/10 14 63 2010/11 7+ 70+ Hiroko Miyamoto

  15. Detector Calibration Hiroko Miyamoto

  16. The Dust Logger ash layer 404nm CW Laser Light blocking brushes Photon counter Understanding of ice properties key to reliable event reconstruction J. Geophys. Res. 111 (2006) D13203 Hiroko Miyamoto

  17. A Scattering Absorption Polar Ice Optical Properties ice bubbles dust dust Measurements: ►in-situ light sources ►atmospheric muons Average optical ice parameters: λabs ~ 110 m @ 400 nm λsca_eff ~ 20 m @ 400 nm Hiroko Miyamoto

  18. Dark Freezer laboratory: Test all optical sensors for ~2 weeks at temperatures -55°C to +20°C Hiroko Miyamoto

  19. N2 N2 laser Beyond the general calibration… 2D PMT Scan Absolutely calibrated (Golden)PMT PMT/DOM Absolute Efficiency

  20. DOM 4π Scan N2 N2 laser Beyond the general calibration… Absolutely calibrated (Golden)DOM PMT/DOM Absolute Efficiency

  21. The Absolute Chain: Standard Candle and Golden DOMs~Detector calibration in situ SC • Known position and shape • Nitrogen (337 nm) pulsed laser • Cone reflected resembles cascades • Pointing-up • 1-10 PeV ne cascade equiv. GD GD • Absolute calibrated with nitrogen 337 nm laser • distance from SC 132, 233, 248 m • relative angle to SC -11.9, 56.2, 58.4 deg SC 130.04m Hiroko Miyamoto

  22. DAQ and trigger setup • Test data taking started since Feb.2006. Effective data started since June 2nd. • 5 DOMs Local Coincidence trigger • ~106 GB/day (~40GB/day with compression) data rate • ~4.8GB/day data are transferred to northern hemisphere via satellite network using several kinds of filtering. • e.g., filtered data which contains >= 80 hit DOMs are filtered as EHE data. • The satellite bandwidth will increase up to ~14GB/day in the future • All data recorded tapes will be carried to the northern sphere by people back from the SP. • ~1.3x107 InIce triggered events per day (~145Hz) with full-time operation Hiroko Miyamoto

  23. Data Example Event viewer の絵 Hiroko Miyamoto

  24. Science ongoing… (some examples) Hiroko Miyamoto

  25. m t t- E = 10 TeV Event Topologies ντ+N→τ travel ~2km τ→ντ+hadrons m e + N e- +X t + N t- +X 10 TeV   0.65o (E/TeV)-0.48 (3TeV < E < 100TeV) 375 TeV e at 1 PeV, Ø~500m 10 PeV  (500 m  track) Hiroko Miyamoto

  26. nt t- Tau Search • Decay modeBranching fraction • τ → ντ + e + νe 17.8% • τ → ντ + X(hadronic) ~65% • τ → ντ + μ + νμ 17.4% Double Bang <~20PeV (Learned & Pakvasa 1995) double bang / lollipop μ “Lollipop” – half double bang Beacom, Bell, Hooper, Pakvasa & Weiler 2005 “Sugar daddy” [DeYoung, Razzaque, & Cowen, forthcoming] τ Hiroko Miyamoto

  27. EHE neutrinos from EHECRs GZK neutrino nm • The standard scenario m EHE-CR p • EHE cosmic-ray • induced neutrinos • The main energy range: En ~ 109-10 GeV nm ne e Beyond the Standard Model X • Exotic scenarios • Top-Down neutrinos • decays/interaction of massive particles • (topological defects, SUSY, micro black hole, …) • The main energy range: En ~ 1011-15 GeV Hiroko Miyamoto

  28. EHE Events in the Earth CR down-going m • General neutrino event ID a through the Earth up-going events • Earth is opaque for EHE neutrino • EHE neutrino induced events are coming from above asdown-going EHE n m m,t m,t m t North ng t m EHE neutrino mean free path ln ~ 100 km << REarth sccnN ~ 10-6~-4 mb ng up-going nm < 1PeV nm > PeV Hiroko Miyamoto

  29. GZK neutrinos / background Atmospheric m GZK m GZK t IceCube Preliminary EGZK >> EAtmm S. Yoshida et. al. (2004) Phys. Rev. D 69 103004 IceCube Preliminary up down GZK neutrino induced lepton and atmospheric muon fluxes at the IceCube depth Hiroko Miyamoto

  30. GZK neutrinos / background (Simulation) GZK m Atmospheric m GZK t IceCube Preliminary Npe (Number of Photoelectrons) is an integrated waveform charge divided by single pe charge • Tentative "signal cut": • Npe > 5.0e5 • cos(q) < 0.1, Npe > 1.0e5 Hiroko Miyamoto

  31. Real Data Example: NPEs, NDOMs-NPEs # Very Very Preliminary!! Base cut # of DOMs < 80 DOMs filtering log10NPE log10NPE Note that: this is just 2 weeks data Hiroko Miyamoto

  32. Conclusions • IceCube (with 9 strings) performs as expected and collects high quality physics data • Majority of DOMs fully functional (~99%) • On our way to instrument one cubic km (2010/11) • First IceCube physics analyses have started • 6 months data are stored by now • Looking forward for IceCube’s rich physics potential Hiroko Miyamoto

  33. END Hiroko Miyamoto

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