Introduction IceCube Detector Neutrino Detection Principles

1. IceCube neutrino telescope@SouthPole - a new window on the universe Joanna Kiryluk LBNL/UC Berkeley Introduction IceCube Detector Neutrino Detection Principles Status of the Construction and Performance Summary

2. Cosmic Rays ? SNR Greisen, Zatsepin And Kuzmin (1966) GZK cutoff UHE What’s the origin of Cosmic Rays with E up to 1020 eV ? The puzzle unresolved almost a century after CR discovery

3. Multi-Messenger Astronomy Where do UHE cosmic rays come from? • protons: directions scrambled by magnetic fields • -rays : straight-line propagation • protons, -rays & neutrinos as probes of the high-energy Universe - do not point back to the source

7. Neutrinos:straight-line propagation, unabsorbed, but difficult to detect Multi-Messenger Astronomy Where do UHE cosmic rays come from? • protons: directions scrambled by magnetic fields • -rays : straight-line propagation but reprocessed in the sources (difficult to prove that they are associate with CR); extragalactic backgrounds absorb E>TeV • protons, -rays & neutrinos as probes of the high-energy Universe - do not point back to the source

8. Expected n flux from galactic point sources, example SNR: RXJ 1713-3946 Christian Stegmann et al. , J.Phys.Conf.Serv.60 (2007) 243

9. NeutrinosfromGZKinteractions GZK neutrinos - very low but guaranteed flux (GZK CRs exist!) cosmic rays interact with the microwave background cosmic rays disappear, neutrinos appear Expect ~ 1 event per km2 per year

10. (Ultra-) high-energy neutrino detectors Neutrino telescopes: • Primarily aimed at > TeV , e.g. IceCube /AMANDA, Antares … • Also sensitive to PeV, EeV , but limited area • New directions with effort to detect: Giant air showers detectors sensitive to ~EeV  e.g. Auger Radio detection - threshold in EeV range , e.g. Anita Extraterrestrial neutrinos - discovery potential! The only confirmed extraterrestrial low energy neutrino sources detected so far are the Sun and the supernova SN1987A

11. THE ICECUBE COLLABORATION Sweden: Uppsala Universitet Stockholm Universitet USA: Bartol Research Institute, Delaware Pennsylvania State University UC Berkeley UC Irvine Clark-Atlanta University University of Maryland IAS, Princeton University of Wisconsin-Madison University of Wisconsin-River Falls Lawrence Berkeley National Lab. University of Kansas Southern University and A&M College, Baton Rouge University of Alaska, Anchorage Germany: Universität Mainz DESY-Zeuthen Universität Dortmund Universität Wuppertal Universität Berlin MPI Heidelberg RWTH Aachen UK: Imperial College, London Oxford University Netherlands: Utrecht University Japan: Chiba university Belgium: Université Libre de Bruxelles Vrije Universiteit Brussel Universiteit Gent Université de Mons-Hainaut ANTARCTICA Amundsen-Scott Station New Zealand: University of Canterbury 33 institutions, ~250 members http://icecube.wisc.edu

12. Science potential with IceCube is vast: • Neutrino point source search (nm • Diffuse searches ( ne, nmand nt more sensitive if there are more sources IceCube physics topics • Atmospheric neutrinos • Cosmic Ray (C.R.) composition • Supernova (SN) • Gamma Ray Bursts • Search for exotic particles and new physics. Vol 315 (2007) http://www.sciencemag.org/content/vol315/issue5808

13. The IceCube Detector Counting House 1450 m AMANDA 2450 m Instrumenting 1km3 of Antarctic Ice to detect extraterrestrial neutrinos IceTop Surface air shower array InIce 70+ strings, each with 60 digital optical modules (DOM) 17 m between modules 125 m string separation IceCube will detect neutrinos of all flavors at energies from 1011 eV to 1020 eV

14. Digital Optical Module (DOM) DOM - a complete data acquisition system: • internal digitization and time stamping the photonic signals from the PMT • can perform PMT gain and time calibration • transmitting digital data to the surface Main Board PMT Main Board (most of electronics) - PMT output collected with fast waveform digitizer chips that sample the signal 128 times at 200-700 MSPS - PMT signal is fed into 3 parallel 10-bit ADC with a nominal gain ratios 0.25:2:16. Combined they provide wide dynamic range from single p.e. to thousands p.e.

15. DOM 51 DOM 52 DOM 53 DOM 54 Time Resolution from LED flashers Method:flash an LED on a DOM and measure the arrival time of light reaching a nearby DOM RMS variation of time delay measured with flashers for 59 DOM pairs on one string. Photon arrival time delay at DOM 52 when DOM 53 is flashing. For most of the DOMs resolution better than 2 ns

16. Neutrinos: How do we see them? Phototubes Muon neutrino Electron neutrino (km long) Track: + increased detection volume +  points along, i.e. to source - cosmic ray  background - ok energy measured • Cascade: e-m or hadronic showers • must be in detector •  background (brems’ng) • limited pointing capability • + good energy measurement

17. Neutrinos Signature (Simulations) 300m Muon neutrino Electron neutrino Tau neutrino a) Eµ=10 TeV ~ 90 hits E = 10 PeV E = 375 TeV +N+... b) Eµ=6 PeV ~1000 hits  +hadrons Double-bang signature above ~ 1 PeV Very low background Pointing capability E ~ dE/dx, E> 1 TeV Energy Res. log(E)~0.1-0.2 Poor Angular Resolution Energy Res. : log(E)~0.3 Angular Res.: 0.8 -2 deg

18. Origin of the neutrinos observed in the detector • atmospheric neutrinos (mostly ) dN/dE~E-3.7 • neutrinos from charm decay In the atmosphere dN/dE~ E-2.8 • astrophysical neutrinos dN/dE~E-2.0 (model) signal M.Kowalski [astro-ph/0505506]

19. Extraterrestrial Neutrinos: Signals and backgrounds Low energy: Distinguish: -  (CR vs) by their direction -  (atmospheric vs extrater.) by energy High energy: Above 105 TeV - small  and bg produced in CR interactions with the Earth atmosphere. Distinguish flavor by their topology Neutrinos (all flavors) interact in(or close to) the detector via: Muon channel: Cascade channel:

20. IceCube at the South Pole IceCube Geographic South Pole Counting House Drill Site Amundsen-Scott South Pole Station AMANDA Skiway

21. Transportation upgrades to Antartica…. Getting there is half the fun New C-17 Old C-141 (photo by RGS)

22. Schedule and Logistics The new South-Pole station • Can work from December to mid-February • Logistics are a huge concern • Power - expensive! • 3 winterover scientists operate and maintain instrument during winter • Weather is always a factor

23. Field team deals very well with issues and harsh conditions

24. Hotwater drill system Hose reel Drill tower DOMs

25. 36 h Hole Drilling Depth (m) • Design goal: • 40 hours to drill a hole • 2500 m deep, 60 cm dia. holes • 5 Megawatt hot water drill • Speeds to 2.2 m/minute Time 2007: Independent firn drill Successfully used for three holes. Expected to save about 2 holes per season.

26. AMANDA 78 IceCube Deployments to Date 74 73 72 • 1424 sensors deployed, and 1403 sensors (98.5%) are commissioned and being used • Comparison to AMANDA-II: • 85 of 677 sensors (12.5%) are not usable for technical reasons 67 2004-2005 1 string deployed First data astro-ph/0604450 66 65 58 57 56 59 48 47 46 50 49 2005-2006 8 string deployed 40 39 38 30 2006-2007 13 strings deployed 29 21 1+8+13 = 22 strings to date Goal >=14 strings/season Completion by 2011. More than 25 % of full detector installed.

27. 2007 13-strings Deployment • Physics Run - started May 2007 • Updated DAQ, triggers, monitoring system April 29 2007 (commissioning) IceDust layer (low rate) 0 2450m 50m 1450m

28. Dust Logger signal DOM Occupancy depth (m) depth (m) labs~110m@400nm lsca~ 20m@400 nm Average optical ice parameters: Ice Properties: scattering and absorption Scattering length varies from 6 to 30m depending on depth and location of dust layers (deposited by e.g. volcanic events over past thousands of years) • Measurements: in-situ light sources, atmospheric muons and Dust Loggers (records dust layers with cm resolution): Probability a DOM is hit in evts that have >7 hits on a string Understanding ice properties - key to modeling IceCube

29. Dust Logger

30. String 57 DOM 60 Sphere 1 Sphere 2 Weight Stack Bubble Camera - 2007 deployment

32.  tracks lose energy by emitting , e+e- pairs and hadronic interactions (via virtual ) Particle () Tracking • Charged particles emit Cherenkov radiation angle  = Cos-1(1/n) = 410 • The photons scatter (L ~ 25 m) • Some (<10-6) photons are observed in photodetectors • We measure points 0-30 meters from the  track • Angular resolution < 10 for long tracks DOM m Noise e+e- p pair-creation  photo-nuclear bremsstrahlung

33. 2006 data: 90 days with 9 strings Data selection done online at S. Pole and transferred by satellite North Neutrino-induced muon candidate Atmospheric muon neutrinos in 2006 Dust layer

34. IC-9strings (first) analysis: Atmospheric muon neutrinos in 2006 • After cuts: 234 events measured (211 expected from atm.MC) • Reconstructed direction Horizon Reconstructed Zenith Angle  (deg) Reconstructed Azimuth Angle  (deg) Contamination at the horizon likely due to mis-reconstructed events (single shower) as being below the horizon. arXiv:0705.1781 [astro-ph]

35. IC-22 run status May 23, 2007 - start of IceCube science run • Event rate: 610 Hz • Raw data: 180 GB/day • Uptime to date: 92% • Events recorded by June 28, 2007 1.65 x 10^9 • Continuous data taking … Downgoing muons (background) Azimuth distribution illustrates detector response. Sufficient data to observe (diffuse) non-atmospheric neutrinos?

36. Dec Jan Feb Mar April IC22  IC36+ Schedule IC22 Science run IC36+ Science run String Commissioning Finish Latecomers pDAQ IC36+ Commissioning(95%) Calibration (Geometry, DOMs) P&F IC36+ Commissioning IC 36+ verification Current status: Ready to go….winterovers arrive on ice Oct 22!! Bulk of drillers arrive on Oct 31

37. Future Plans • Above ~ 1016 eV, the expected  rates in IceCube are small • A ~100 km3 detector is needed to see GZK  • Protons and  have limited range. Only probe sensitive to ‘EHE universe’ > 50 megaparsecs away • Coherent radio and/or acoustic detection of EHE showers may allow for an affordable detector

38. Summary • IceCube construction is well underway • - More than 25% complete. • - Completed detector in 2011. • Physics analysis underway. • IceCube IC-9 atmospheric muon neutrino results • IC-22 analyses on-going • Stay tuned!

39. Solar panels Antenna array ANITA Gondola & Payload RF Cherenkov Overall height ~8m air Ice- radio transparent medium neutrino Cascade: ~10m length Antarctic Impulsive Transient Antenna Experiment ANITA Utilizes Askaryan effect searching for GZK neutrinos with radio detection in Antarctic ice

40. STATUS: 35 day flight this season 2006/7 ~15 days of good data • - Haven’t unblinded yet • - Might see a GZK neutrino, if lucky Payload was crunched on landing Next flight in 2008/9

41. ARIANNA concept100 x 100 station array, ~1/2 Teraton Ross Ice Shelf, Antarctica ~300m

42. Sensitivity and limits • ANITA sensitivity, 45 days total: ~5 to 30 GZK neutrinos IceCube: high energy cascades ~1.5-3 GZK events in 3 years S. Barwick

43. Neutrino fluxes - upper limits Oscar Blanch-Bigas

44. Count rates 0 5 10 sec Amanda-II Supernova Monitor AMANDA II: 95% of Galaxy IceCube: Milky Way + LMC msec time resolution You are here LMC IceCube

45. Master Clock Distribution Data Acquisition and Trigger • “Full” DAQ software & trigger • Select time regions of interest using multiplicity, topology • Events == time window • Collect data for these windows • Data filtering (muon, cascade) • Reconstruct events • Select interesting events for satellite transmission • Monitoring, calibration, logging, control functions,… InIce