The Status of IceCube

1. The Status of IceCube Mark KrasbergUniversity of Wisconsin-Madison RICH 2004 Conference, Playa del Carmen, Mexico Dec 3, 2004

2. IceCube – a next generation n observatory a cubic kilometer successor to AMANDA • Detection of Cherenkov light from • the charged particles produced when • aninteracts 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. “Up-going” (from Northern sky) “Down-going” (from Southern sky) AMANDA-II 19 strings 677 OMs Trigger rate: 80 Hz Data years: >=2000 Optical Module PMT looking downward PMT noise: ~1 kHz

4. A ice bubbles dust dust Polar Ice Optical Properties Scattering Absorption Average optical ice parameters: λabs ~ 110 m @ 400 nm λsca_eff ~ 20 m @ 400 nm Measurements: ►in-situ light sources ►atmospheric muons

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 km2 • geometry optimized for detection of TeV – PeV (EeV)n’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. AMANDA muon event CC muon neutrino interaction  track nm + N  m +X

9. Track Reconstruction in Low Noise Environment 1200 m • Typical event: 30 - 100 PMT fired • Track length: 0.5 - 1.5 km • Flight time: ≈4 µsecs • Accidental noise pulses: 10 p.e. / 5000 PMT / 4 µsec IceTop IceCube AMANDA

10. Eµ=10 TeV, 90 hits Eµ=6 PeV, 1000 hits 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.

11. t decays 1 PeVt(300m) nt t

12. n- flavors and energy ranges pulse •Filled area: particle id, direction, energy • Shaded area: no particle id

13. Galactic center IceCube effective area and angular resolution for muons further improvement expected using waveform info Median angular reconstruction uncertainty ~ 0.8 • E-2nmspectrum • quality cuts and background suppression (atmmreduction by ~106)

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

15. Point sources: event rates Flux equal to 3x current AMANDA limit dN/dE = 10-6*E-2/(cm2 sec GeV) Compared to AMANDA-II: 7 times more PMT --> 50 to 100 times more atmosph. neutrinos @ better angular and energy resolution

16. IceCube Digital Optical Module

17. penetrator HV board flasher board pressure sphere DOM main board delay board PMT optical gel mu metal cage 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 • design requirement • Noise rate ~1 kHz • SN monitoring within • our Galaxy

18. 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 DOM Mainboard • fast ADC recording at 40 MHz over 5 ms • event duration in ice HV Board Interface 2xATWD • Dead time < 1% Dynamic range - 200 p.e./15 ns - 2000 p.e./5 ms energy measurement (TeV – PeV) FPGA 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

19. DOM Waveform Capture High Gain • Altera Excalibur ARM922t mP+ 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 ms wide). Medium Gain Low Gain t  400 ns window

20. Calibration • Calibration of sensors in the lab at temperatures between -20 and -55C (deep ice: -18C to -42C) • LED Flashers on each module, 12 LEDs, in 6 directions and 2 angles (10^10 photons) • Special “high energy” lasers • Timing calibration is feature of DOM: 5 nsec • IceTop: High level cross calibration of muon tracks with air showers. • 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

24. PMT HV Calibration C O U N T S CHARGE G A I N Nominal HV Setting VOLTAGE

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

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

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

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

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

30. AMANDA Deployment

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 IceCube strings IceTop tanks 4 8 Jan 2005 16 32 Jan 2006 32 64 Jan 2007 50 100 Jan 2008 68 136 Jan 2009 80 160 Jan 2010 • Data taking begins early next year

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

33. 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 USA (12) Japan Europe (12) Venezuela • Chiba university, Japan • University of Canterbury, Christchurch, NZ • Universidad Simon Bolivar, Caracas, Venezuela New Zealand ANTARCTICA • Universität Wuppertal, Germany • Uppsala university, Sweden • Stockholm university, Sweden • Imperial College, London, UK • Oxford university, UK • Utrecht,university, Netherlands • Universite Libre de Bruxelles, Belgium • Vrije Universiteit Brussel, Belgium • Université de Mons-Hainaut, Belgium • Universität Mainz, Germany • DESY-Zeuthen, Germany • Universität Dortmund, Germany