An Overview of the IceCube Neutrino Telescope

1. An Overview of the IceCube Neutrino Telescope Kael Hanson University of Wisconsin – Madison 8th International Conference on Advanced Technology and Particle Physics Villa Olmo, Como, Italy

2. IceCube Collaboration • Bartol Research Institute, University of Delaware, Newark, DE 19716, USA • Fachbereich 8 Physik, BUGH Wuppertal, D-42097 Wuppertal, Germany • Université Libre de Bruxelles, Science Faculty CP230, Boulevard du Triomphe, B-1050 Brussels, Belgium • CTSPS, Clark-Atlanta University, Atlanta, GA 30314, USA • Dept. of Physics, Chiba University, Chiba 263-8522 Japan • DESY-Zeuthen, D-15738 Zeuthen, Germany • Astrophysics, Imperial College, London SW7 2BW, UK • Institute for Advanced Study, Princeton, NJ 08540, USA • Dept. of Physics and Astronomy, University of Kansas, Lawrence, KS 66045, USA • Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA • Dept. of Astronomy and Astrophysics, Penn State University, University Park, PA 16802, USA • Dept. of Physics, Southern University, Baton Rouge, LA 70813, USA • Dept. of Physics, University of California, Berkeley, CA 94720, USA • Institute of Physics, University of Mainz, Staudinger Weg 7, D-55099 Mainz, Germany • Dept. of Physics, Oxford University, Oxford OX1 3PU, UK • Dept. of Physics, University of Maryland, College Park, MD 20742, USA • Dept. of Physics, George Mason University, Fairfax, VA 22030 USA • University of Mons-Hainaut, 7000 Mons, Belgium • Departamento de Física, Universidad Simón Bolívar, Caracas, 1080, Venezuela • Dept. of Astronomy, University of Wisconsin, Madison, WI 53706, USA • Dept. of Physics, University of Wisconsin, Madison, WI 53706, USA • SSEC, University of Wisconsin, Madison, WI 53706, USA • Physics Dept., University of Wisconsin, River Falls, WI 54022, USA • Division of High Energy Physics, Uppsala University, S-75121 Uppsala, Sweden • Faculty of Physics and Astronomy, Utrecht University, NL-3584 CC Utrecht, The Netherlands • Dept. of Physics, Stockholm University, SE-10691 Stockholm, Sweden • Vrije Universiteit Brussel, Dienst ELEM, B-1050 Brussels, Belgium • Department of Physics & Astronomy, University of Canterury, Christchurch 8020, New Zealand K. Hanson - IceCube Overview

3. The South Pole Site IceCube is two tightly coupled sub-detectors which share triggers and contribute data to common event structures: • the InIce array: 80 strings of 4800 DOMs arranged in hexagonal lattice 1400 m – 2400 m beneath surface • the IceTop array: a surface array of frozen water tanks for monitoring airshowers, to provide a veto for InIce array, and calibration of InIce array. 2 tanks per station at top of each string. 2 DOMs per tank. K. Hanson - IceCube Overview

4. Ice Properties K. Woschnagg – UC Berkeley K. Hanson - IceCube Overview

5. Detecting Passing Charged Particles In Ice K. Hanson - IceCube Overview

6. IceCubeNeutrino Flavor Detection K. Hanson - IceCube Overview

7. Recent AMANDA Results Diffuse sources search with AMANDA-II detector NEW AMANDA-II Point Source Search (astro-ph/0309585) Sky map of 699 neutrino candidate events. No evidence for excess. AMANDA –II Preliminary K. Hanson - IceCube Overview

8. AMANDA Publications • Supernovae: Astropart.Phys.16:345-359, 2002 • Point Sources:Astrophys.J.583:1040-1057, 2003 • Diffuse Cascades:Phys.Rev.D67:012003, 2003 • Atmospheric Neutrinos:Phys.Rev.D66:012005, 2002 • WIMPS:Phys.Rev.D66:032006, 2002 K. Hanson - IceCube Overview

9. Detector Performance(astro-ph/0305196) • Cascades: • Localized to detector volume • Very good vertex and energy resolution • Muons: • Travel great distances through ice • Sub-degree pointing resolution (ptsrc) K. Hanson - IceCube Overview

10. IceCube Sensitivity to Diffuse nFluxes astro-ph/0305196 K. Hanson - IceCube Overview

11. The Digital Optical Module (DOM) • IceCube detector contains 4800 InIce and 360 IceTop modules. • Each DOM is autonomous DAQ platform • In situ digitization of PMT pulses for increased S/N and better dynamic range: 200 pe instantaneous, 104 pe integrated • DOM asynchronously records hits – buffers until surface readout requests data (8 MB acquisition memory) • Hits time stamped with local oscillator. This must be trans-formed at surface to UT /w/ overall time res. of < 5 ns! • DOM-to-surface communication bandwidth approximately 1 Mbit K. Hanson - IceCube Overview

12. The Digital Optical Module (DOM) (2) K. Hanson - IceCube Overview

13. Photomultiplier Tube • Large area (10” dia.) bi-alkali photocathode deposited on borosilicate glass envelope. • 10 dynode stages in box-and-line configuration • Fast pulse (6.5 ns width; < 3 ns risetime; < 3 ns FWHM TTS) • Very low noise (250 cps typ. @ -40 ºC and ¼ pe counting threshold)! • High gain: 108 @ 1500 V typ. • IceCube operating range ~ 107 with modified bleeder Hamamatsu R7081-02 K. Hanson - IceCube Overview

14. PMT Noise vs. Temperature K. Hanson - IceCube Overview

15. High Voltage Base • Passive Base • Modular HV design: • HV generator • Digital interface board • “Classical” resistor-divider HV bleeder • Proportional 1st dynode • High-Z bleeder (70 MΩ) • HV Base • 0-2048 V • 12-bit DAC • 12-bit ADC readback • Two solutions with differing HV unit but identical digital interfaces: • “Active” • “Passive” • Active Base • 2× Cockroft-Walton • 1st dynode fixed – 600 V • Anode voltage digitally controllable • Technology used in some AMANDA-II OMs + ANTARES K. Hanson - IceCube Overview

16. Pressure Sphere • Vendor – many decades of experience with deep sea applications + AMANDA OMs • 13” O.D., 0.5” thick borosilicate glass hemispheres joined under negative pressure • Single 5/8” penetrator brings in power, signals. • Low noise (require < 300 Hz induced spe rate in PMT) • UV transparency: T50 ~ 350 nm or less and residual sensitivity down to 315 nm: l-2 Cherenkov g. K. Hanson - IceCube Overview

17. CPLD Memories Flasher Board Interface Power + Signal Excalibur HV Board Interface 2x ATWD Analog Front End DOM Mainboard K. Hanson - IceCube Overview

18. K. Hanson - IceCube Overview

19. DOM Waveform Capture and DSP • 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. High Gain Medium Gain Low Gain t K. Hanson - IceCube Overview

20. DOM Surface Readout: DOR and DOM Hub • DOM signals readout on surface by “DOMHub” computer • DOR card (DORC?) – 32-bit PCI card – is the last piece custom h/w in the IceCube DAQ system. • 8 DOM per DOR, 8 DOR per DOMHub → 1 DOMHub per InIce string. IceTop application uses only 4 DOM per DOR → 10 IceTop DOMHubs • Industrial rackmount SBC computer (dual 1 GHz PIII) + passive backplane • Applications in DOMHub direct readout, buffer data, and re-transmit data packets over IP to downstream DAQ elements. K. Hanson - IceCube Overview

21. IceCube DAQ in 2 Minutes! • All hits from InIce string readout and presented to String Processor • String Processor converts DOM timestamps to UT; searches for temporal-spatial coincidences; passes “trigger primitives” to trigger processor. All single hits buffered until EB releases! • InIce / IceTop Trigger Processors may apply additional trigger criteria • Global Trigger receives trigger info from IceTop and InIce; may apply additional trigger criteria • Event Builder receives trigger chains; queries String Processors (IceTop Data Handlers) for hits; builds events; passes events to online filter system. K. Hanson - IceCube Overview

22. Status and Summary • We are building the IceCube neutrino telescope: • Hot water drill system nearing completion; to be shipped to South Pole this year. • Production of DOMs has begun • 24 ‘engineering’ DOMs built in US • 60 pre-production DOM will build Jan ’04 (US, Germany, Sweden) • 400 deployment DOM will build Apr ’04 (US, Germany, Sweden) • IceTop prototype tank /w/ DOMs deployed this year • We are on-track for deployment of up to six strings in ’04-’05 season • 1 km2·yr achieved 2007! • Construction of IceCube from 2005 to 2010 when full detector will be online. K. Hanson - IceCube Overview

23. The End K. Hanson - IceCube Overview

24. Magnetic Shield & Gel • Magnetic Shield • Made from high-mu metal (Russian origin) • Reduces terrestrial magnetic on interior of cage by approx. 50% • Increases collection efficiency of PMT • Gel • Provides index matching of PMT/glass • Also the mechanical stabilizer and shock absorber of PMT + board stack assembly • GE RTV6156 A+B (degassed, mixed, degassed again) • Remains rubbery at very low temp. K. Hanson - IceCube Overview

25. Flasher Board • 12 UV LEDs mounted at 60º separation around perimeter of board (2 per site) • Capable of producing 106 to 1010 photons per pulse. • LED current fed back into ATWD channel for precision timing and light emission profiling. • Used for studies of ice optics, calibration of OM relative geometry, energy reconstruction studies • Not used for calibration of local OM – small LED on DOM mainboard exists for that purpose. K. Hanson - IceCube Overview