IceCube a kilometer-scale deep-ice observatory in Antarctica Olga Botner Uppsala university, Sweden Neutrino 2004, June 14-19, icecube.wisc.edu

copyright ©West Nottinghamshire College 2003 The location – at the bottom of the world Distance from Paris km

and landing Aerial View of the Amundsen- Scott Research Station going there … Photo

IceCube – a ”next generation” observatory  kilometer-scale 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 deposited p.e. waveform read out Expected performance wrt AMANDA increased effective area/volume superior angular resolution superior energy resolution

astronomy requires km-scale detectors  ultrahigh energy ’s associated with the sources of high energy cosmic rays  top-down scenarios: decays of massive cosmological relics  bottom-up scenarios: ”cosmic accelerators” accreting black holes (eg AGN) colliding neutron stars/black holes  fireball (eg GRB)  cosmogenic ’s  supernova ’s  dark matter  WIMP, Kaluza-Klein  exotica  monopoles, Q-balls, mini black holes p + (p or  )     e,  The Science

IceCube concept Deep ice array  80 strings / 60 OM’s each  17 m OM 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 Surface array IceTop  2 frozen-water tanks (2 OM’s each) on top of every string

IceTop + IceCube: 1/3 km 2 sr for coincident tracks VETO against  All downward events E > 300 TeV with trajectories inside IceTop  Larger events falling outside CALIBRATION  of angular response with tagged  Expect ~100 tagged air showers/day with multi-TeV  ’s in IceCube Muon survey of IceCube

Large showers with E ~ PeV will clarify transition from galactic to extra-galactic cosmic rays IceCube layout Measure  energy spectrum  chemical composition Measure  energy spectrum  chemical composition Cosmic Ray physics Showers triggering 4 stations give ~300 TeV threshold for EAS array Showers triggering 4 stations give ~300 TeV threshold for EAS array IceCube - Icetop coincidences Investigate transition to extragalactic CR Investigate transition to extragalactic CR Small showers (2-10 TeV) associated with the dominant  background detected as 2-tank coincidences at a station. Small showers (2-10 TeV) associated with the dominant  background detected as 2-tank coincidences at a station. Energy range eV eV

Digital Optical module (DOM)  a self-contained ”mini”-DAQ records timestamps digitizes stores transmits to surface at request  an 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 Dark noise rate < 1 kHz  SN monitoring within our Galaxy

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)

-time stamped w.f. recorded & analyzed - downgoing muons detected - photon timing accuracy in ice < 8 ns - local clock calibration < 5 ns r.m.s. - 15% of waveforms have > 1 p.e. IceCube design works

IceCube physics performance simulations benefit from AMANDA experience IceCube will be able to identify   tracks from   for E > eV  cascades from e for E > eV   for E > eV Background mainly downgoing cosmic ray  ’s (+ time coinc.  ’s from uncorrelated air showers)  exp. rate at trigger level ~1.7 kHz  atm.  rate at trigger level ~300/day Rejected  using direction/energy/flavor id  temporal/spatial coincidence w. source for E  < 1PeV focus on the Northern sky for E > 1PeV sensitive aperture increases w. energy  full sky observations possible E µ =10 TeV

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

Diffuse  flux / Point sources Objective (after removal of atm  background):  reject the steep energy spectrum of atm  retain as much signal as possible from a (generic) E -2 spectrum Use optimized energy cutE   number of hit OM’s E µ =6 PeV, 1000 hitsE µ =10 TeV, 90 hits Diffuse  hard E  cut E  > 100 TeV Point sources  softer E  cut + spatial correlation

Assume generic flux dN/dE = 10 –7 E -2 (cm -2 s -1 sr -1 GeV) Expect ~10 3 events/year after atm  rejection ~75 events/year after energy cut cf background 8 atm atm v signal Sensitivity (1 y): 8.1  E -2 (cm -2 s -1 sr -1 GeV) blue: after atm  rejection red: after E  cut Diffuse  flux

Steady point sources Search cone 1  opening half-angle + ”soft” energy cut (< 1 TeV) Transient point sources – eg GRB Essentially background-free search energy, spatial and temporal correlation with independent observation For ~1000 GRB’s observed/year expect (looking in Northern sky only)  signal: 12  background (atm ): 0.1 Sensitivity GRB (1 y): ~0.2  WB Excellent prospects for detection of GRB ’s within 1-2 years -> if models realistic Sensitivity point sources (1 y): 5.5  E -2 (cm -2 s -1 GeV)

Cascades e  e L cascade ~10 m small cf sensor spacing  ” spherical” energy deposition  at 1 PeV, Ø cascade ~ 500 m  ~10% in log(E/TeV) E = 375 TeV IceTop veto on cosmics IceTop veto on cosmics C.O.G. inside array C.O.G. inside array   “double bang” ~300m for PeV  E << 1 PeV 2 cascades coincide E  1 PeV ”double bang” E >> 1 PeV ”lollipop” (partial containment, reconstruct  track + 1 cascade)  sensitivity to all flavors  4  coverage For diffuse flux expect similar sensitivity in the cascade channel as in the muon channel  Considerable improvement of overall sensitivity

Neutralino dark matter astro-ph/ (Lundberg/Edsjö) WIMP orbits in the solar system perturbed Rates from the Earth affected  Rates from the Sun less affected Direct and indirect searches complementary  Past/present history of solar syst.  Low/high energy tail of  vel. distr.  Disfavored by direct search Sun Earth

AMANDA system IceCube AMANDA IceCube Power consum. 2 MW 5MW Time to 2400 m h h Fuel (gal/hole) Set-up time 5 – 6 weeks d AMANDA IceCube Power consum. 2 MW 5MW Time to 2400 m h h Fuel (gal/hole) Set-up time 5 – 6 weeks d Goals  18 holes/season  2450 m deep  straight within 1m  quality logged Goals  18 holes/season  2450 m deep  straight within 1m  quality logged Enhanced Hot Water Drill

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

Mounting, testing + drop of string with 60 OMs expected to take ~ 20 hours Mounting, testing + drop of string with 60 OMs expected to take ~ 20 hours

Status of IceCube project  many reviews – international and within the U.S. - strongly emphasize the exciting science which can be performed with IceCube  in Jan 2004, the U.S. Congress approved the NSF budget including the full IceCube MRE  significant funding approved also in Belgium, Germany and Sweden  in Feb 2004, NSF conducted a baseline review  “go ahead”  deployment over 6 years IceCube strings IceTop tanks 48Jan Jan Jan Jan Jan Jan 2010

AMANDA / IceCube integration Amanda now runs with TWR  data similar in structure to IceCube  work on a s/w trigger Position of 1 st IceCube strings  as close to Amanda as possible  for verification & cross-calibration  … but logistics and safety requirements 1.1 st IceCube strings: Amanda as calibration device 2.IceCube ~ 20 strings + Amanda: powerful combined detector 3.Full IceCube: Amanda included as a fully integrated, low threshold subdetector CONTINUOUS SCIENCE OUTPUT DURING CONSTRUCTION

 drill development on schedule for operation at Pole in Jan 2005  instrumentation  production for the 4 string first season starts this summer  50% PMTs delivered – on schedule  3 DOM production sites  Wisconsin st season  DESY 60 1 st season  Sweden 50 1 st season  spheres ordered – 40 K depleted Benthos (dark noise ~0.8 kHz)  DOM mainboard – LBNLtests OK  DAQ S/W developed  data transfer DOM  DOM Hub  Data Collection prog tested  implementation for first season’s DAQ  cables – Ericsson, Sweden / JDR, Netherlands  preparing for analysis of early data (calibration, testing)  4 DOM’s are collecting IceTop data using test s/w Status of IceCube construction

View of DOMs IceTop tank with hood at the South Pole – Nov 2003

IceTop Stations with DOMs – January 2004 Digitized muon signals from DOMs Amplitude (ATWD counts) vs time (ns) power cable signal, freeze control, temperature control cables

1st challenge – successful deployment of strings 2004/2005 Summary IceCube is for real ! - and moving ahead at full speed AMANDA experience provides for huge benefits - both logistics-wise and for simulations/reconstruction IceCube is expected to be  considerably more sensitive than AMANDA  provide new opportunities for discovery  with IceTop – a unique tool for cosmic ray physics  first data for Neutrino 2006  data taking during construction  first data augment AMANDA data  later AMANDA an integral part of IceCube

USA (12) Europe (11) 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 Universite Libre de Bruxelles, Belgium Vrije Universiteit Brussel, Belgium Université de Mons-Hainaut, Belgium Universität Mainz, Germany DESY-Zeuthen, Germany Universität Wuppertal, Germany Uppsala university, Sweden Stockholm university, Sweden Imperial College, London, UK University of Oxford, UK NIKHEF, Utrecht, Netherlands Universität Wuppertal, Germany Uppsala university, Sweden Stockholm university, Sweden Imperial College, London, UK University of Oxford, UK NIKHEF, Utrecht, Netherlands Chiba university, Japan University of Canterbury, Christchurch, NZ Chiba university, Japan University of Canterbury, Christchurch, NZ ANTARCTICA Universidad Simon Bolivar, Caracas, Venezuela

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