Albrecht Karle University of Wisconsin - Madison for the IceCube Collaboration IceCube Current status, recent results and future prospects

Albrecht Karle, APS meeting, April Ankle 1 part km -2 yr -1 knee 1 part m -2 yr -1 T. Gaisser 2005 Cosmic rays Candidate sources (accelerators): Cosmic ray related: – SN remnants – Active Galactic Nuclei – Gamma Ray Bursts Other: – Dark Matter – Exotics Guaranteed sources (known targets): Atmospheric neutrinos (from π and K decay) Galactic plane: CR interacting with ISM, concentrated on the disk   GZK (cosmogenic neutrinos) p    +  n  + (p  0 ) Cosmic Rays and Neutrino Sources

Albrecht Karle, APS meeting, April Neutrino production  eeee ee    Beam-dump model:  0 →  -astronomy  ± →  -astronomy Neglecting  absorption     Targets: p or ambient  Integrated flux in neutrinos similar to that in photons

4 Neutrino Fluxes energy ranges of IceCube High energy neutrino astronomy: Small fluxes, Need large detectors, Note wide energy range MeV energy Supernova neutrinos

5 Neutrino Topologies

IceCube Univ Alaska, Anchorage UC Berkeley UC Irvine Clark-Atlanta University U Delaware / Bartol Research Inst University of Kansas Lawrence Berkeley National Lab University of Maryland Pennsylvania State University University of Wisconsin- Madison University of Wisconsin- RiverFalls Southern University, Baton Rouge Univ Alaska, Anchorage UC Berkeley UC Irvine Clark-Atlanta University U Delaware / Bartol Research Inst University of Kansas Lawrence Berkeley National Lab University of Maryland Pennsylvania State University University of Wisconsin- Madison University of Wisconsin- RiverFalls Southern University, Baton Rouge  Universität Mainz Humboldt Univ., Berlin DESY, Zeuthen Universität Dortmund Universität Wuppertal MPI Heidelberg RWTH Aachen  Universität Mainz Humboldt Univ., Berlin DESY, Zeuthen Universität Dortmund Universität Wuppertal MPI Heidelberg RWTH Aachen Uppsala University Stockholm University Uppsala University Stockholm University Chiba University Chiba University Universite Libre de Bruxelles Vrije Universiteit Brussel Université de Mons- Hainaut Universiteit Gent Universite Libre de Bruxelles Vrije Universiteit Brussel Université de Mons- Hainaut Universiteit Gent Univ. of Canterbury, Christchurch University of Oxford University Utrecht United states Europe JapanNew Zealand Icecube team at the Pole,

7 IceTop InIce Air shower detetor threshold ~ 300 TeV 80 Strings, 60 Optical Modules 17 m between Modules 125 m between Strings : 1 String : 8 Strings AMANDA ( ) 19 Strings 677 Modules IceCube total of 40 Strings 80 IceTop tank : 13 Strings : m 2450m

8 new South Pole station new South Pole station

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10 Hotwater drill Thermal power: 5 MW 60 cm diameter hole, 2m/min Time to complete: 35 hrs Time between two strings: ~50h

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PMT: 10 inch Hamamatsu Power consumption: 3 W Digitize at 300 MHz for 400 ns with custom chip 40 MHz for 6.4 μs with fast ADC Dynamic range 500pe/15 nsec Send all data to surface over copper 2 sensors/twisted pair. Flasherboard with 12 LEDs Local HV Clock stability: ≈ 0.1 nsec / sec Synchronized to GPS time every ≈10 sec Time calibration resolution = 2 nsec Digital Optical Module (DOM) LED flasher board main board Digitized Waveform

13 IceCube Laboratory n 17 racks of computers n Power: 60 kW total for full IceCube n Filtered data sent by satellite: ~40GB/day, raw data on tape

14 IC40 Noise rates (April 8, 2008)

15 Time resolution ~1ns n Time difference between neighboring DOMs fired with (bright) flasher pulses: 1 ns. n For SPE pulses add PMT jitter (3 nsec)

16 Getting simulations right - example: down going muons Zenith distribution at trigger level Multiplicity distribution (number of sensors with hits)

17 Carefully model optics of ice! Dark and transparent environment for Cherenkov light detection Polar ice:  abs (blue) ~ m eff. scat ~ 20 to 40 m dust layer muon energy loss in the detector Hits, which orginated from muons are plotted versus depth

18 Clarity of deep ice n Illustrated by big cosmic- ray event  ~500 PeV, ~1000  u Light spreads out below dust layer at 2100 m u Even though muon bundle is ranging out u Absorption, scattering 2 x more favorable in deep ice

19 Detectors optimal at high energies IC22, IC80 analysis not optimized yet (reconstruction and cuts optimized for IC9) IC9 measured: 233 in 137d, expected 227 Atmospheric neutrinos expected rates per yr: IC22: >6000 IC80: >40000 Effective area for neutrinos Angular resolution (integral plot) IC22: 1.5° IC80: 0.8° Strong rise (cross section, muon range)

20 Skymap of 7 years of AMANDA-II 5yr max significance: 3.74   2.8  Significance 3yr max significance: 3.73   1.5  Max Significance  =54 o,  =11.4h 3.38  95 of 100 data sets randomized in RA have a significance  3.38  --> No signal

21 Selected Sources The probability of obtaining p  for at least one of the 26 sources is 20% The Crab: –Significance decreases –Still a minor upward fluctuation Upward Fluctuations: –LS I –Geminga –MGRO J Downward Fluctuations: –Mrk 421 Source  90 P-value Crab MGRO J Mrk Mrk LS I Geminga

22 Milagro Sources, Stacking Search Apply stacking search to 6 Milagro sources with >5  pretrial significance –Exclude PWN sources (Crab, Geminga) Improves per-source flux sensitivity and discovery potential by a factor of 4 compared to a fixed-point search for any of the six sources Halzen, Kappes, O’Murchada [arXiv: ]

IceCube 9 (data) IceCube 9 String Configuration: June November 2006 ~ days livetime With Quality Cuts: Real Data: 233 neutrino event candidates Atmospheric neutrino rate: 1.7 per day median angular resolution: 2.0° sigma

IceCube 22 String Configuration: June March 2008 ~ 250 days livetime With Quality Cuts: Simulated Skymap: ~ 5,000 neutrino event candidates Atmospheric neutrino rate: 20 per day median angular resolution: 1.5° sigma IceCube 22 (simulated skymap) IceCube 80 Rate: ~200 per day Resolution: 0.8° Use Shadow of moon for precise calibration > 25 per day Will have real sky map soon. 280 days livetime

Flux limits and sensitivities AMANDA-5yrs: astro-ph/ IceCube:stro-ph/ MACRO 2044 d IceCube 365 expected IC9 137d

26 Atmospheric Neutrinos AMANDA 7 year Data sample: 6163 events Energy range: ~100 GeV to ~10 TeV Preliminary MC scaled to data by 0.9, Within uncertainty of detector effective area Zenith angle distribution MC True energy distribution IceCube 80: events / year

Where do we stand? diffuse fluxes Diffuse fluxes Monte Carlo: number of hit channels Monte Carlo: true neutrino energy

28 Going to higher energies IceCube 80, 1yr arXiv: , apj arXiv: , prd Figure from

29 High energy analysis in AMANDA Simulated background cosmic ray muon shower event

30 Zenith Direction of GZK events Search for GZK neutrino above horizon in progress

31 Flasher event LED flasher calibration event E ~ 1 PeV Visible up to 600m distance

32 Detection of large events Energy = 375 TeV 1 PeV shower: Based on flasher events: Horizontal diameter about 1 km!!! ~ 800m upper part ~1200 m lower part -Substantially bigger than original simulations. For Flasher events with IC40, go to:

33 Cosmic ray physics: IceCube with IceTop surface array Area--solid-angle ~ 1/3 km 2 sr (including angular dependence of EAS trigger) Calibration Veto of HE shower background Cosmic Ray/air shower physics up to eV –~100 Coincident events above eV –Measure spectrum and mass composition at end of galactic spectrum –50 coincident evts/year with E > 1e18 eV –Very good mass independent energy resolution <0.1 in log(E)

34 Each 2 m diameter IceTop tank contains two DOMs. IceTop tank

35 Optimization

36 Larger geometries: Higher cross over Greater gain at high energies High Energy IceCube Optimization study Investigating options for optimized positioning of last 9 strings Motivation: Improve high energy response. Significant impact on drilling. RESULT: Gain in effective area 10% to 30% (50% at GZK energies ) (depending on configuration) IceTop coincidence event rate increases

Three-prong hybrid air shower studies – (1) IceTop, (2) Muons in deep ice, (3) Radio –--> Talk by Jan Auffenberg Options for IceTop Radio Extension Expansion of surface array   Veto for UHE neutrino detection InIce Infill surface array   Hybrid CR compositon

38 SPATS - South Pole Acoustic Test Setup Study feasibility of acoustic UHE neutrino detection at South Pole Measure acoustic properties of Antarctic ice 4 strings in 4 IceCube holes 7 transmitters and sensors on each string  Talk by Freija Descamps

39 Radio ice Cherenkov detectors Two antenna clusters (AURA) deployed for R&D at depth of 300m and 1400m. Taking data.  Talk by Hagar Landsman

40 R&D Future extension ideas: UHE Radio Augmentation acoustic instrumentation ICERAY GZK neutrinos ( eV), at lowest possible cost: o(10)/yr Hybrid events with IceCube –Primary vertex calorimetry in radio, HE muon or tau secondary in IceCube  Talk by John Kelley

41 AMANDA has set the most constraining limits for astrophysical neutrinos. Conclusions The 4 th IceCube construction season: 40 strings+80 IceTop Tanks! Construction on budget and on schedule 80 strings in 2011 Analysis of first IceCube science run of IC22 underway. First results this fall. Collaboration working on R&D for options for a larger GZK neutrino detector. Did not cover all topics such as Supernova searches or neutrino physics,….

Diffuse Flux is shown at the level of the current upper limit from AMANDA-II: d  /dE = 5  GeV -1 cm -2 s -1 sr -1 (E/GeV) -2 IceCube 22 (simulation)

Gamma-ray Bursts Razzaque et a l Meszaros & Waxman Murase & Nagatake Waxman Waxman&Bahcall

Example: Noise behavior Figure shows total noise counts of IC22 over a period of ~50 hours. Apply 200µsec deadtime (supernova mode excludes afterpulses) Average rate / DOM (w deadtime): ~260 Hz DOM noise: stable and as expected.