The Status of IceCube Mark Krasberg University of Wisconsin-Madison RICH 2004 Conference, Playa del Carmen, Mexico Dec 3, 2004

2 IceCube – a next generation observatory a cubic kilometer successor to AMANDA Detection of Cherenkov light from the charged particles produced when a  interacts with rock or ice Direction reconstructed from the time sequence of signals Energy measurement: counting the number of photoelectrons entire waveform read out Expected performance wrt AMANDA increased effective area/volume superior angular resolution superior energy resolution

3 PMT noise: ~1 kHz Optical Module “Up-going” (from Northern sky) “Down-going” (from Southern sky) AMANDA-II 19 strings 677 OMs Trigger rate: 80 Hz Data years: >=2000 PMT looking downward

Measurements: ► in-situ light sources ► atmospheric muons Average optical ice parameters: λ abs ~ nm λ sca_eff ~ nm bubbles dust A ice Scattering Absorption Polar Ice Optical Properties

5 IceCube Science Goals High energy neutrinos from transient sources (GRBs and Supernovae) Steady and variable sources of high energy neutrinos (AGNs and SNRs) Sources of high energy cosmic rays WIMPs (Dark Matter) Unexpected or exotic phenomena Cosmic Ray Physics

6 IceCube Concept Deep In-Ice Array  80 strings / 60 DOMs each  17 m DOM spacing  125 m between strings  hexagonal pattern over 1 km 2  geometry optimized for detection of TeV – PeV (EeV) ’s  based on measured absorption & scattering properties of Antarctic ice for UV – blue Cherenkov light Ice Top Surface Array  2 frozen-water tanks (2 DOM’s each) above every string

7 Amundsen-Scott South Pole Research Station

8  + N   +X  + N   + X muon neutrino CC muon neutrinointeraction  track  track AMANDA muon event

9 Track Reconstruction in Low Noise Environment Typical event: PMT fired Track length: km Flight time: ≈4 µsecs Accidental noise pulses: 10 p.e. / 5000 PMT / 4 µsec AMANDA IceCube IceTop 1200 m

Energy Reconstruction Small detectors: Muon energy is difficult to measure because of fluctuations in dE/dx IceCube: Integration over large sampling + scattering of light reduces the energy loss fluctuations. E µ =6 PeV, 1000 hitsE µ =10 TeV, 90 hits

11 1 PeV   (300m)    decays

- flavors and energy ranges Filled area: particle id, direction, energy Shaded area: no particle id pulse

13 IceCube effective area and angular resolution for muons Galactic center  E -2  spectrum  quality cuts and background suppression (atm  reduction by ~10 6 ) further improvement expected using waveform info Median angular reconstruction uncertainty ~ 0.8 

Macro Baikal Amanda Diffuse Fluxes - Predictions and Limits IceCube Sensitivity after 3 years

Point sources: event rates Atmospheric Neutrinos AGN* (E -2 ) Sensitivity (E -2 /(cm 2 sec GeV)) All sky/year (after quality cuts) 100,000 - Search bin/year year: Nch > 40 (E > 7 TeV) x Flux equal to 3x current AMANDA limit dN/dE = *E -2 /(cm 2 sec GeV) Compared to AMANDA-II: 7 times more PMT --> 50 to 100 times more atmosph. better angular and energy resolution

16 IceCube Digital Optical Module

Digital Optical Module  records timestamps digitizes waveforms transmits to surface at request via digital communications can do local coincidence triggering  optical sensor 10 inch Hamamatsu R-7081 mu metal cage PMT penetrator HV board flasher board DOM main board pressure sphere optical gel delay board design requirement Noise rate ~1 kHz SN monitoring within our Galaxy

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

19 DOM Waveform Capture t Altera Excalibur ARM922t  P+ 400k gate FPGA on a single chip CPU runs data acquisition, testing facility, and diagnostic utilities FPGA controls communications interface, time critical control of DAQ hardware, fast feature extraction of waveforms 2× ATWD – each with 4 channels capable of digitizing 128 samples at rates from 0.25 – 1.0 GHz. 2 of them for ‘ping-pong’ mode. 3 gain channels in ATWD for complete coverage of PMT linear region 10-bit, 40 MHz FADC for capture of extended photon showers in the ice (6  s wide). High Gain Medium Gain Low Gain  400 ns window

Calibration 1. Calibration of sensors in the lab at temperatures between -20 and -55C (deep ice: -18C to -42C) 2. LED Flashers on each module, 12 LEDs, in 6 directions and 2 angles (10^10 photons) 3. Special “high energy” lasers 4. Timing calibration is feature of DOM: 5 nsec 5. IceTop: High level cross calibration of muon tracks with air showers. 6. Shadow of the Moon (at 25 to 30 degree elevation): Muon rate of about 1500 Hz will allow to calibrate angular resolution in astrophysical coordinates in short time scales.

21 DOM Testing DFL (Dark Freezer Lab) is large, dark, cold container which holds N test stations (N is site- dependent) each of which schematically looks like the figure. Optical fiber system carries light from optics breadboard (diode laser, LED pulser, monochromator-tuned lamp) to each DOM. Optics spreads light evenly out across PMT photocathode.

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

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24 PMT HV Calibration COUNTSCOUNTS CHARGE VOLTAGE GAINGAIN Nominal HV Setting

25 Final Acceptance Test Results Detection of Synchrotron across the street In-Ice Noise Rate ~ 1 kHz Time Resolution < 3ns Noise Stability Monitor detected Synchrotron radiation from the SRC, Physical Sciences Lab, Wisconsin

26 Triggering on Cosmic Rays Single PE triggerLocal Coincidence triggering for DOMs with 1.5m vertical separation

27 A six hour flight from New Zealand to McMurdo Station, via C-141 “Starlifter” Getting to the South Pole

28 A three hour flight from McMurdo to South Pole Station, via C-130 “Hercules”

29 Hose-reel at South Pole (Jan 2004) Hose-reel with hose, built at Physical Sciences Laboratory UW-Madison (Nov 2003)

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31 Summary IceCube is deploying 256 DOMs next month! IceCube is expected to be considerably more sensitive than AMANDA provide new opportunities for discovery with IceTop – a unique tool for cosmic ray physics Data taking begins early next year IceCube strings IceTop tanks 48Jan Jan Jan Jan Jan Jan 2010

32 IceCube drill camp construction site of the first hole, Nov 25, 2004

33 USA (12) Europe (12) Venezuela Japan New Zealand Bartol Research Institute, Delaware, USA Univ. of Alabama, USA Pennsylvania State University, USA UC Berkeley, USA Clark-Atlanta University, USA Univ. of Maryland, USA Bartol Research Institute, Delaware, USA Univ. of Alabama, USA Pennsylvania State University, USA UC Berkeley, USA Clark-Atlanta University, 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 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 Universität Mainz, Germany DESY-Zeuthen, Germany Universität Dortmund, Germany Universite Libre de Bruxelles, Belgium Vrije Universiteit Brussel, Belgium Université de Mons-Hainaut, Belgium Universität Mainz, Germany DESY-Zeuthen, Germany Universität Dortmund, Germany Universität Wuppertal, Germany Uppsala university, Sweden Stockholm university, Sweden Imperial College, London, UK Oxford university, UK Utrecht,university, Netherlands Universität Wuppertal, 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 Chiba university, Japan University of Canterbury, Christchurch, NZ ANTARCTICA Universidad Simon Bolivar, Caracas, Venezuela