1. 1 IceCube: A Neutrino Telescope at The South Pole Chihwa Song UW-Madison photographed by Mark Krasberg 4 th Korean Astrophysics Workshop May 17-19, 2006

2. 2 Multi-messenger Astronomy Radio Infrared Optical Gamma Ray deflected absorbed p  ee p +   + n  +radio  +IR  e + e -  +MW Local Group 3C279 Mrk421 Gal Center <100 Mpc 1-10 9 TeV

3. 3 Neutrino Fluxes Confirmed extraterrestrial sources: Sun, SN1987A

4. 4 Cosmic Accelerators Discovery of neutrinos would confirm hadronic acceleration

5. 5 Origin of Astrophysical Neutrinos Source candidates: AGN, SNR, GRB, microquasar Protons accelerated at source produce pions which decay into neutrinos: n e : n m : n t = 1 : 2 : 0 p + p (or      e       n e : n m : n t = 1 : 1 : 1 @ source @ Earth oscillation (maximal    mixing)

6. 6 Neutrino Telescopes Detection R equirements: - small neutrino cross section  huge detector volume - optically transparent medium  use water or ice Neutrino telescopes: - Water: Baikal, ANTARES, NESTOR, NEMO, KM3 - Ice: AMANDA, IceCube (successor of AMANDA)

7. Neutrino Detection Detect Cherenkov light from charged particles produced by neutrinos  : CC e : NC, CC   : NC, CC   : NC Cascade Muon track CC NC q = 41 o

8. 8 E = 10 TeV e E = 375 TeV   Neutrino Flavor E = 10 PeV travel ~2km Two showers separated by roughly 50  (E t  /PeV) m 80 string IceCube ~300m    0.65 o (E /TeV) -0.48 (3TeV < E  < 100TeV)

9. Background Zenith angle Miss-reconstructed down-going events Up-going atmospheric neutrino events

10. 10 Signal: harder spectrum (E -2 ) than background (Fermi acceleration) E -3.7 atmospheric E -2 flux True neutrino energy Number of fired OMs Diffuse Neutrinos from unidentified faint sources

11. 11

12. 12 USA (14) Europe (15) Japan New Zealand Alabama University, USA Bartol Research Institute, Delaware, USA Pennsylvania State University, USA UC Berkeley, USA UC Irvine, USA Clark-Atlanta University, USA University of Alaska, Anchorage, USA Univ. of Maryland, USA IAS, Princeton, USA University of Wisconsin-Madison, USA University of Wisconsin-River Falls, USA LBNL, Berkeley, USA University of Kansas, USA Southern University and A&M College, Baton Rouge, USA Universite Libre de Bruxelles, Belgium Vrije Universiteit Brussel, Belgium Université de Mons-Hainaut, Belgium Universiteit Gent, Belgium Humboldt Universität, Germany Universität Mainz, Germany DESY Zeuthen, Germany Universität Dortmund, Germany Universität Wuppertal, Germany MPI Heidelberg, Germany Uppsala university, Sweden Stockholm university, Sweden Imperial College, London, UK Oxford university, UK Utrecht university, Netherlands Chiba university, Japan University of Canterbury, Christchurch, NZ ANTARCTICA The IceCube Collaboration

13. 13 IceCube InIce 80 strings 60 OMs / string 17 m vertical spacing 125 m between strings IceTop 80 stations 2 frozen-water tanks / station 2 OMs / tank Super Kamiokande 40m

14. 14 main board LED flasher board PMT base PMT 33 cm Benthosphere Digital Optical Module (DOM) Hamamatsu R7081-02 (10”, 10-stage, 10 8 gain) - Time-stamp at the PMT - Capture complex waveforms at PMT anode with analog Transient Waveform Digitizer (ATWD)

15. 15 back 2xATWD FPGA Memories HV Board Interface CPLD Oscillator (Corning Frequency Ctl) running at 20 MHz maintains df/f < 2x10 -10 2 ATWDs 4 channels with different gains working in ping-pong fashion recording at 420 MHz over 0.4 ms signal complexity at the start of event Dead time < 1% Dark noise rate: ~700 Hz fADC recording at 40 MHz over 6.4 ms event duration in ice DOM Mainboard

16. 16 Hot Water Drill speed: 1.5m/min

17. 17 Drilling String 49 – drill stopped for ~one hour at ~2300 meters

18. 18 Freezing Ice Noise rates increase during freeze-in String freezes from top (colder ice) to bottom (warmer ice) Top Bottom

19. 19 Dust Logger ash layer

20. 20 Ice Properties Scattering bubbles Absorption Average optical parameters: abs ~ 110 m @ 400 nm sca ~ 20 m @ 400 nm dust layer DOM occupancy at string 21

21. 21 Showers triggering 4 stations give ~300 TeV threshold for EAS array IceTop Array - Cosmic ray physics - Calibration of IceCube - Tagging background for study and rejection

22. 22 Two ice tanks 3.6 m 2 x 1 m deep IceTop Station To DAQ IceCube Drill Hole 10-15 m Local coincidence cable

23. 23 04/05 1 IceCube string 8 IceTop tanks 05/06 8 IceCube strings 24 IceTop tanks Deployment Status

24. 24 An Up-going Event

25. 25 Data/MC Comparison Event reconstruction with only one string

26. 26 Down-going Muon Events

27. 27 A Flasher Event Color: arrival time Size: amplitude 6 vertical (top) LEDs 6 horizontal (bottom) LEDs (Single LED run)

28. 28 Galactic center Capabilities of IceCube Sources of extraterrestrial neutrinos Steady and transient point sources Unidentified faint sources MeV neutrino bursts from Supernovae Cosmic rays Composition Energy spectrum Neutrino physics Oscillations Cross-sections New physics WIMP (Sun, Earth) Magnetic monopoles Q-balls Lorentz invariance...

29. 29 Diffuse Neutrinos No significant excess was seen with AMANDA! by Jessica Hodges Astrophysical and prompt neutrino models

30. 30 Rates of contained coincident events 125 m grid, km 2 air shower array at 690 g/cm 2 E threshold ~ 300 TeV for > 4 stations in coincidence Useful rate up to ~ EeV Total rate 1-2 kHz Small showers trigger station if within ~30 m Direct tag for few % of muon background (~50 Hz out of 1-2 kHz) IceTop

31. 31 Bursts of low-energy (MeV) neutrinos from core collapse supernovae The produced positron is emitted almost isotropically - AMANDA sees 90% of the galaxy - IceCube will see out to the LMC (Large Magellanic Cloud, ~50 kpc) SN Neutrino Search detection radius AMANDA IceCube 30 kpc 0 5 10 sec Count rates Simulation (IceCube) O(10cm) long tracks SNEWS (SuperNova Early Warning System) is a collaborative effort among Super-K, SNO, LVD, KamLAND, AMANDA, BooNE and gravitational wave experiments Rate increase on top of dark noise  e + p  n + e +

32. 32    The Sun sinks maximally 23 o below the horizon at the south pole Horizontal events are very important!!  qq l + l - W + W - Z o Higgs…  Indirect search Velocity distribution   Cosmic Rays:  WIMP Annihilation in the Sun

33. 33  Penetrating muon bundle in shower core Incident cosmic- ray nucleus Threshold ~ 10 18 eV to veto this background 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) EeV Neutrino Detection

34. 34 New Method - Radio –One cluster (4 antennas) in the next season –Increase to 2 clusters in the following seasons ~50m Motivation: difficulties to cover very large detector volume with optical sensors ROCSTAR (Retrofitted OptiCal SysTem Adapted for Radio)

35. 35 New Method - Acoustic Calibration method in water has been developed In-situ calibration in ice is needed SPATS (South Pole Acoustic Test Setup)

36. 36 Summary IceCube will be a powerful all-flavor neutrino detector Significant improvement in angular and energy resolutions IceTop will measure cosmic rays up to ~ EeV with high resolution AMANDA will overlap the lower energy tail of IceCube sensitivity AMANDA has taken data for the 7th year String deployment speed reached expectation DOM survival rate is very good (~99%) Verifications of the new IceCube strings in progress The current IceCube is larger than AMANDA and provides science quality data On-going activities (radio, acoustic) toward ~100km 3 detector

37. 37 Time Delay Time delay in arrival times of photons due to scattering in ice depends on the distance with respect to the muon track.

38. 38 Glacial Ice Flow Rigid down to 2000 m Stuck at bedrock Lagging behind Modeling from temperature profile Flow direction

39. 39 A Neutrino Candidate Event

40. 40 Point Source Search Final sample (4 yrs): 3369 0.214.502SS433 1.255.3610Crab Nebula 0.405.214Cygnus X-1 0.775.046Cygnus X-3 0.383.7151ES1959+650 0.685.586Markarian 421 Flux Upper Limit  90% (E >10 GeV) [10 -8 cm -2 s -1 ] Expected backgr. (4 years) Nr. of events (4 years) Source Search for excesses of events compared to the background from: 1. the full Northen sky 2. a set of selected candidate sources 64% chance occurrence

41. 41 Search for Clusters in Northern Sky 2000-2003 data: 807 days livetime 3329 neutrino events observed Cluster search radius between 2.25 o – 3.75 o w.r.t.  Largest significance = 3.4  (92% chance occurrence) No significant excess observed Significance map

42. 42 Search For WIMPs Limits on muon flux from Earth centerLimits on muon flux from Sun

43. 43 Surprises?

44. 44 Sensitivities & Limits average flux upper limit [cm -2 s -1 ] sin  AMANDA-B10 AMANDA-II IceCube 1/2 year * all-flavor limits ν μ (A-II 4yr) ν e +ν μ +ν τ (cascades A-II 1yr) ν e +ν μ +ν τ (UHE B10 1yr) ν e (cascades B10 1yr) ν μ (B10 1yr) ν μ (A-II 1yr) ν e +ν μ +ν τ (UHE A-II 1yr) Icecube (1yr) WB bound Limit Sensitivity Diffuse search (E -2 flux hypothesis) Steady point source sensitivity