A km 3 Neutrino Telescope: IceCube at the South Pole Howard Matis - LBNL for the IceCube Collaboration

SPIE Hawaii - August 2002H. Matis – Lawrence Berkeley National Laboratory2 Neutrino Astronomy measuring s by its µ  Stable particles:  p,  Stable particles:  p,  Astrophysical Sources GRB, AGN, Super Novae GRB, AGN, Super Novae GZK (p +CMB  ) GZK (p +CMB  ) Topological defects Topological defects  Backgrounds Atmospheric  ’ s Atmospheric  ’ s Atmospheric ’ s Atmospheric ’ s IceCube Earth Accelerator Target

SPIE Hawaii - August 2002H. Matis – Lawrence Berkeley National Laboratory3 IceCube 1400 m 2400 m South Pole IceTop Skiway  IceCube is designed to detect neutrinos of all flavors at energies from 10 7 eV (SN) to eV  80 Strings  4800 PMT  Instrumented volume: 1 km 3  Depth: 1400 m to 2400m Amanda

SPIE Hawaii - August 2002H. Matis – Lawrence Berkeley National Laboratory4 South Pole Dark sector AMANDA IceCube Dome Skiway

SPIE Hawaii - August 2002H. Matis – Lawrence Berkeley National Laboratory5 Detecting s  s interact in earth  Produce µ (follows path of )  Detect Cherenkov light in ice with phototubes buried in the ice  Detect upward µ s  Ice filters downward cosmic µ s

SPIE Hawaii - August 2002H. Matis – Lawrence Berkeley National Laboratory6 1 Km Measure  energy at the detector by counting the number of fired PMTs and the total light. E µ =10 TeVE µ = 6 PeV Simulated  + N   - + X

SPIE Hawaii - August 2002H. Matis – Lawrence Berkeley National Laboratory7 Other Reactions e + N  e - + X Electron Cascade 1 PeV ≈ 500 m diameter PeV  (300 m)    decays  + N  - + X

SPIE Hawaii - August 2002H. Matis – Lawrence Berkeley National Laboratory8 IceCube String OM Spacing: 17 m HV and Base Gel Main Cable Glass pressure sphere rated to 10,000 psi Outer diameter: 13” 60 optical sensors/string photomultiplier 1400 m 2400 m DOM String

SPIE Hawaii - August 2002H. Matis – Lawrence Berkeley National Laboratory9 Digital Optical Module - (DOM)  Self-triggers on each pulse  Captures waveforms  Time-stamps each pulse  Digitizes waveforms  Performs feature extraction  Buffers data  Responds to Surface DAQ  Set PMT HV, threshold, etc 33 cm DOM Board

SPIE Hawaii - August 2002H. Matis – Lawrence Berkeley National Laboratory10 Requirements for One Element Digital Optical Module (DOM)  Time resolution:< 5 ns rms  Waveform capture > 250 MHz for first 500 ns > 250 MHz for first 500 ns ~ 40 MHz for 5000 ns ~ 40 MHz for 5000 ns  Dynamic Range > 200 PE / 15 ns > 200 PE / 15 ns > 2000 PE / 5000 ns > 2000 PE / 5000 ns  Dead-time< 1%  OM noise rate < 500 Hz ( 40 K in glass sphere)  1 to 10,000 photons that are incident over several µs  High dynamic range waveform recording

SPIE Hawaii - August 2002H. Matis – Lawrence Berkeley National Laboratory11 Time-stamping in DOM  Course time-stamp local 40 MHz clock local 40 MHz clock Very stable  f/f ~ 6 x /s Very stable  f/f ~ 6 x /s  t ~ 25 ns not enough by itself  t ~ 25 ns not enough by itself Okay for triggering Okay for triggering  Fine time-stamp pulse sample # in ATWD pulse sample # in ATWD  t ~ 3.3 ns (algorithm can do better)  t ~ 3.3 ns (algorithm can do better)

SPIE Hawaii - August 2002H. Matis – Lawrence Berkeley National Laboratory12 Time Synch- ronizing Modules DOM Surface  t down =  t up =1/2(T round-trip -  t) tt

SPIE Hawaii - August 2002H. Matis – Lawrence Berkeley National Laboratory13 Network  Copper-wire 0.9 mm  in twisted-pair Adequate for ICECUBE needs: Power:<3 Watts/DOM (<20% loss) Power:<3 Watts/DOM (<20% loss) Timing:<5 ns rms throughout time-base Timing:<5 ns rms throughout time-base Messaging: control, code modifications Messaging: control, code modifications Data:~ kBytes/second/DOM Data:~ kBytes/second/DOM  InIce Two DOMS/pair, to save $, bulk, logistics  IceTop One DOM/pair, to get bandwidth

SPIE Hawaii - August 2002H. Matis – Lawrence Berkeley National Laboratory14 DAQ Network Architecture String - Electronics in the ice Global Timing

SPIE Hawaii - August 2002H. Matis – Lawrence Berkeley National Laboratory15 AMANDA String 18  Springboard for transition to IceCube  41 DOMs deployed in 99/00 season; 37 operational  Test bed: download new code into ice  Communicate and program in North America

SPIE Hawaii - August 2002H. Matis – Lawrence Berkeley National Laboratory16 String 18 DOM Board Oscillator

SPIE Hawaii - August 2002H. Matis – Lawrence Berkeley National Laboratory17 Digital ATWD Waveforms Single Photon ADC Spectra Complex MHz Time ADC Charge Hi Gain Low Gain No Gain Clock “Slow” ADC ATWD Channels 1 - 4: 1.7 ns/sample for 217 ns ADC: 60 ns/sample for 7.7  s “Bucket” ~ 600 Hz

SPIE Hawaii - August 2002H. Matis – Lawrence Berkeley National Laboratory18 Timing with “Phone Wire” to few ns  Transit time for 2.5 km twisted pair: ~12  s  Rise-time after propagation ~ 2  s (~1/t)  Use a bipolar “Time-Mark” signal pulse  Digitize time-mark 20 MHz, 10-bit  Fit leading edge & baseline : 3.5 ns rms

SPIE Hawaii - August 2002H. Matis – Lawrence Berkeley National Laboratory19 Timing with µ s T (DOM N ) T (DOM N+1 )  T = T (DOM N ) - T (DOM N+1 ) Two clear components: random coincidences (flat) correlated light (peak at ~ 0) 12 m  t - ns

SPIE Hawaii - August 2002H. Matis – Lawrence Berkeley National Laboratory20 Reconstructed  Event Only first hit in each OM shown Down flow of light No “early photons” Late hits consistent with: light scattering, or a second  ? Down going 

SPIE Hawaii - August 2002H. Matis – Lawrence Berkeley National Laboratory21 String 18 Performance  Timing: 3.5 ns rms (very stable)  SPE spectrum:as expected  PMT Gain Drift:<<0.2 %/week  LED Beacons:~8 ns rms (ice optics)  Down going  :observed  µ waveforms:~15% have > 1 “hit”

SPIE Hawaii - August 2002H. Matis – Lawrence Berkeley National Laboratory22 Summary  IceCube – New detector under development to explore astrophysical s  Decentralized timing with digital technology Measure full waveform Measure full waveform Provides more information for reconstruction Provides more information for reconstruction More detail for physics discovery More detail for physics discovery Feature extraction - less data to record and transmit Feature extraction - less data to record and transmit  Can synchronize separate and remote elements to several ns  Fully functional prototypes tested with muons in AMANDA  Prototypes meet or exceed IceCube requirements

SPIE Hawaii - August 2002H. Matis – Lawrence Berkeley National Laboratory23 Institutions: 11 US, 9 European, 1 Japanese and 1 Venezuelan; 1.Bartol Research Institute, University of Delaware (*) 2.BUGH Wuppertal, Germany (*) 3.Universite Libre de Bruxelles, Brussels, Belgium (*) 4.CTSPS, Clark-Atlanta University, Atlanta, USA 5.DESY-Zeuthen, Zeuthen, Germany (*) 6.Institute for Advanced Study, Princeton, USA 7.Lawrence Berkeley National Laboratory, Berkeley, USA (*) 8.Department of Physics, Southern University and A\&M College, Baton Rouge, LA, USA 9.Dept. of Physics, UC Berkeley, USA (*) 10.Institute of Physics, University of Mainz, Mainz, Germany (*) 11.University of Mons-Hainaut, Mons, Belgium (*) 12.Dept. of Physics and Astronomy, University of Pennsylvania, Philadelphia, USA (*) 13.Dept. of Astronomy, Dept. of Physics, SSEC, University of Wisconsin, Madison, USA (*) 14.Physics Department, University of Wisconsin, River Falls, USA (*) 15.Division of High Energy Physics, Uppsala University, Uppsala, Sweden (*) 16.Dept. of Physics, Stockholm University, Stockholm, Sweden (*) 17.Dept. of Physics, University of Alabama, USA 18.Vrije Universiteit Brussel, Brussel, Belgium (*) 19.Chiba University, Japan 20.Dept. of Astrophysics, Imperial College, UK 21.Dept. of Physics, University of Maryland, USA 22.Universidad Simon Bolivar, Caracas, Venezuela(*) also in AMANDA IceCube Collaboration

SPIE Hawaii - August 2002H. Matis – Lawrence Berkeley National Laboratory24 The End