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Neutrino Astronomy at South Pole: Latest Results & Perspectives for IceCube Observation

Explore recent findings from AMANDA & outlook for IceCube in neutrino astronomy. Learn about cosmic rays & telescope function.

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Neutrino Astronomy at South Pole: Latest Results & Perspectives for IceCube Observation

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  1. Neutrino Astronomy and Cosmic Raysat the South PoleLatest results from AMANDA and perspectives for IceCubePaolo Desiatidesiati@icecube.wisc.eduUniversity of Wisconsin – Madison XIX European Cosmic Ray SymposiumFirenze (Italy) http://amanda.uci.edu http://icecube.wisc.edu

  2. Who are we ? Bartol Research Inst, Univ of Delaware, USA Pennsylvania State University, USA University of Wisconsin-Madison, USA University of Wisconsin-River Falls, USA LBNL, Berkeley, USA UC Berkeley, USA UC Irvine, USA Univ. of Alabama, USA Clark-Atlanta University, USA Univ. of Maryland, USA IAS, Princeton, USA University of Kansas, USA Southern Univ. and A&M College, Baton Rouge Chiba University, Japan University of Canterbury, Christchurch, New Zealand Universidad Simon Bolivar, Caracas,Venezuela Université Libre de Bruxelles, Belgium Vrije Universiteit Brussel, Belgium Université de Mons-Hainaut, Belgium Universität Mainz, Germany DESY-Zeuthen, Germany Universität Wuppertal, Germany Uppsala Universitet, Sweden Stockholm universitet, Sweden Kalmar Universitet, Sweden Imperial College, London, UK University of Oxford, UK Utrecht University, Utrecht, NL

  3. Where are we ? South Pole Dome road to work AMANDA Summer camp 1500 m Amundsen-Scott South Pole Station 2000 m [not to scale]

  4. “Up-going” (from Northern sky) “Down-going” (from Southern sky) AMANDA-B10 (inner core of AMANDA-II) 10 strings 302 OMs Data years: 1997-99 AMANDA-II 19 strings 677 OMs Trigger rate: 80 Hz Data years: >=2000 Optical Module PMT looking downward PMT noise: ~1 kHz

  5. First year deployment (Jan 2005) 4 IceCube strings (240 OMs) 8 IceTop Tanks (16 OMs) IceTop 160 tanks frozen-water tanks 2 OMs / tank 1200 m IceTop IceCube AMANDA IceCube 80 strings 60 OMs/string 17 m vertical spacing 125 m between strings IceTop Tank deployed in 2004 10” Hamamatsu R-7081

  6. <labs>~ 110 m @ 400 nm <lsca>~ 20 m @ 400 nm Event detection in the ice O(km) long mtracks South Pole ice: the most transparent natural medium ? event reconstruction by Cherenkov light timing ~15 m AMANDA-II mtracks pointing error : 1.5º - 2.5º σ[log10(E/TeV)] : 0.3 - 0.4 coverage : 2p Cascades (particle showers) pointing error : 30º - 40º σ[log10(E/TeV)] : 0.1 - 0.2 coverage : 4p cosmic rays (+SPASE) combined pointing err : < 0.5º σ[log10(E/TeV)] : 0.06 - 0.1 Nucl. Inst. Meth. A 524, 169 (2004) cascades a neutrino telescope Qmn0.65o(En/TeV)-0.48 (3TeV<En<100TeV) Longer absorption length → larger effective volume

  7. Array AMANDA IceCube ν astronomy : physics goals Bottom-Up scenario cosmic accelerator • p + (p or )   + X  e ,+ X • good pointing resolution • good acceptance a neutrino telescope requires ~ km3 scale • Protons which escape are bent => cosmic rays • Photons which escape are absorbed above 50 TeV • Neutrinos escape

  8. ν astronomy : background Background rejection Cosmic ray μmain background • Protons which escape are bent => cosmic rays • Photons which escape are absorbed above 50 TeV • Neutrinos escape Preliminary

  9. ν astronomy : background Atmospheric nm background & calibration beam First energy spectrum > 10 TeV Blobel regularized unfolding Expected high energy nm flux … in this talk nm telescope capability search of high energy nm from extra-terrestrial steady point sources Cosmic Ray measurements • Protons which escape are bent => cosmic rays • Photons which escape are absorbed above 50 TeV • Neutrinos escape Preliminary

  10. d=0o AMANDA-II AMANDA-B10 d=20o d=50o ↑  2 d=70o nm effective area d=0o  d declination d=90o  n telescope : point source search Detection of nm from discrete steady bright or close sources (AGN, …) • cosmic ray m background rejection • good pointing resolution • bin search optimization versus a given signal ( E-2) 1 m2 

  11. 1997 : Ap.J. 583, 1040  (2003) 2000 : PRL 92, 071102 (2004) IceCube : Astrop Phys 20, 507 (2004) * AMANDA-B10 average flux upper limit [cm-2s-1] average flux upper limit [cm-2s-1] AMANDA-B10 AMANDA-II AMANDA-II IceCube 1/2 year d=0o  d declination d=90o  sin(d) sin(d) n telescope : point source search Average upper limit = sensitivity (δ>0°) (integrated above 10 GeV, E-2 signal) (*)optimized for E-2, -3signal * Sensitivity independent of direction lim  0.68·10-8 cm-2s-1 Preliminary

  12. Maximum significance 3.4 s compatible with atmospheric n ~92% n telescope : point source search Preliminary Search for clustering in northern hemisphere • compare significance of local fluctuation to atmospheric n expectations • un-binned statistical analysis • no significant excess 2000-2003 3369 n from northern hemisphere 3438 n expected from atmosphere also search for neutrinos from unresolved sources

  13. Cosmic rays spectrum

  14. 1 km 2 km Cosmic rays spectrum S(30) SPASE-2 + AMANDA ~1/7000km2 sr for coincident tracks IceTop + IceCube 1/3 km2 sr for coincident tracks • IceTop-IceCube • VETO • All downward events Em > 300 TeV with trajectories inside IceTop • Larger events falling outside • CALIBRATION • of angular response and with tagged m • Expect ~100 tagged air showers/day with multi-TeV m’s in IceCube IceTop as muon survey of IceCubez • SPASE-AMANDA • combined angular resolution ~ 0.5o • absolute pointing calibration < 1o • S(30)  Ne particle density at 30m from core •  K50 m energy lost in AMANDA (Em>500GeV ) • Nm lateral distr func at 50m from core K50,S(30)  (Nm, Ne)  (Energy, Mass) SPASE as muon survey of AMANDA K50

  15. AMANDA-B10 IceTop/IceCube energy extension 1015 eV Normalize to direct measurements <ln A> = 2 (JACEE/RUNJOB) Cosmic rays composition SPASE-AMANDA Primary energy resolution ~ 0.07 in log10(Eprim) CR composition measured in 0.5- 6 PeV IceTop-IceCube Covers sub-PeV to EeV energies Improve energy resolution Fluctuations @ knee are smaller @ South Pole e.g SPASE e.g. KASCADE • spectra steeper because of smaller fluctuations at higher energies • mean values shifted by fluctuations • error in mass determination

  16. In press Astroparticle Physics Cosmic rays composition mass-independent high resolution primary energy measurement probing relative change of muonic energy to electromagnetic energy in the shower method robust against systematic uncertainties data are consistent with an increase of cosmic ray mass composition at the knee, between 500 TeV and 5 PeV. Direct measurements

  17. Summary • AMANDA-II is collecting data and increasing statistics. Has reached good sensitivity as neutrino telescope (point sources search) • SPASE-2/AMANDA-B10 indicates increase of CR mass composition @ knee • AMANDA-II is improving other results by tightening constraints on models : • Neutrinos from SN • Neutrinos from WIMP annihilations (Earth and Sun) • Search for neutrinos in coincidence with GRB’s • Search for neutrinos (nm , ne) from unresolved diffuse sources • Search for UHE/EHE extra-galactic neutrinos • CR spectrum and composition • IceCube/IceTop will significantly improve astrophysics in energy range and resolution • IceCube will be a powerful all-flavor neutrino detector (particle physics) • IceTop will open the CR measurements up to ~ EeV with high resolution • AMANDA will overlap the lower energy tail of IceCube sensitivity

  18. thank you “The n“ @ South Pole

  19. Scattering Absorption ice bubbles dust dust Average optical ice parameters: labs ~ 110 m @ 400 nm lsca ~ 20 m @ 400 nm latt ~ 17 m @ 400 nm Measurements: ►in-situ light sources ►atmospheric muons Polar ice optical properties back

  20. Mediterranean sea optical properties abs att Average values 2850÷3250 m Average optical ice parameters: labs ~ 63.3 m @ 440 nm lsca ~ 80.8 m @ 440 nm latt ~ 35.5 m @ 440 nm back

  21. AMANDA : neutrino limits constraint models • Upper limits on diffuse ET neutrino fluxes • Atmospheric ν energy spectrum • Cascade analysis • Ultra High Energy ν search diffuse (B10) UHE/3 cascades/3 Unfolded (last bin) Antares 1 yr IceCube 1 yr back

  22. AMANDA : m Aeff AMANDA-B10 AMANDA-II back

  23. AMANDA : K50 The entire high energy (> 500 GeV) muon bundle is measured over a large volume The light output from all muons is sampled over 500 m length and 150 m laterally K50 is the measure of muon energy lost in a large volume back

  24. AMANDA : K50 normalization Apanasenko et al., Astrop. Phys. 16 , 13 (2001) back

  25. CR composition: fluctuations SPASE/IceTop back KASCADE(-Grande)

  26. CR composition: fluctuations J. Van Buren Diploma Thesis Karlsruhe, 2002 back

  27. Showers triggering 4 stations give ~300 TeV threshold for EAS array Small showers (2-10 TeV) associated with the dominant m background in the deep detector are detected as 2-tank coincidences at a station. Detection efficiency ~ 5% provides large sample to study this background IceTop : EAS detection Large showers with E ~ 100-1000 PeV will clarify transition from galactic to extra-galactic cosmic rays. back

  28. Rates of contained coincident events IceTop • 125 m grid, km2 air shower array at 690 g/cm2 • Ethreshold ~ 300 TeV for > 4 stations in coincidence • Useful rate up to ~ EeV • Total rate 1-2 kHz • Median Eprimary = 3.5 TeV • Small showers trigger station if within ~30 m • Direct tag for few % of muon background (~50 Hz out of 1-2 kHz) back

  29. Incident cosmic-ray nucleus n m Penetrating muon bundle in shower core Threshold ~ 1018 eV to veto this background IceTop : EeV detection Potential to reject this background for EeV neutrinos by detecting the fringe of coincident horizontal air shower in an array of water Cherenkov detectors (cf. Ave et al., PRL 85 (2000) 2244, analysis of Haverah Park) back

  30. Neutrino flavor nt Full flavor ID supernovae ne ne Showers vs tracks nm 9 12 18 21 6 15 Log(ENERGY/eV) Neutrino flavor identification AMANDA flavor ID Tau Neutrinos: • Regeneration: earth quasi-transparent to nt • Enhanced m & cascade flux due to secondary nm, ne IceCube flavor ID, direction, energy IceCube triggered, partial reconstruction back to the end

  31. Galactic center IceCube : m Aeff & resolution back

  32. NEMO : m Aeff & resolution • Up-going muons with E-1 spectrum • 60 kHz background • Reconstruction + Quality Cuts • Nemo20m 140 (5832 OM) • Lattice 125 16 (5600 OM) http://nemoweb.lns.infn.it From Neutrino 2004 talk by P. Piattelli back

  33. Eµ=6 PeV, 1000 hits Eµ=10 TeV, 90 hits IceCube : simulated m track events back

  34. IceCube : sensitivities Diffuse nmsensitivity Point source nmsensitivity back

  35. IceCube : DOM Mainboard back 2 four-channel ATWDs Analog Transient Waveform Digitizers low-power ASICs recording at 300 MHz over first 0.5ms signal complexity at the start of event HV Board Interface 2xATWD • fast ADC • recording at 40 MHz over 5 ms event duration in ice FPGA • Dynamic range • 200 p.e./15 ns • 2000 p.e./5 ms energy measurement (TeV – PeV) Dead time < 1% Memories FPGA (Excalibur/Altera) reads out the ATWD handles communications time stamps waveforms system time stamp resolution 7 ns wrt master clock CPLD oscillator (Corning Frequency Ctl) running at 20 MHz maintains df/f < 2x10-10 back

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