The Status of IceCube

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The Status of IceCube

• Mark KrasbergUniversity of Wisconsin-Madison
• RICH 2004 Conference,
• Playa del Carmen, Mexico
• Dec 3, 2004

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IceCube a next generation n observatory a
cubic kilometer successor to AMANDA

• Detection of Cherenkov light from
• the charged particles produced when
• a n 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

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AMANDA-II 19 strings 677 OMs Trigger rate 80
Hz Data years gt2000


Optical Module
PMT looking downward
PMT noise 1 kHz
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Polar Ice Optical Properties
Scattering
Absorption
Average optical ice parameters ?abs 110 m _at_
400 nm ?sca_eff 20 m _at_ 400 nm
Measurements ?in-situ light sources ?atmospheri
c muons
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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

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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) ns
• based on measured absorption
• scattering properties of
• Antarctic ice for UV blue
• Cherenkov light

• Ice Top Surface Array
• 2 frozen-water tanks
• (2 DOMs each)
• above every string

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Amundsen-Scott South Pole Research Station
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AMANDA muon event
CC muon neutrino interaction ? track
nm N ? m X
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Track Reconstruction in Low Noise Environment
1200 m
IceTop

• 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

IceCube
AMANDA
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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.
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t decays
1 PeV t (300m)
nt t
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n - flavors and energy ranges
pulse
Filled area particle id, direction, energy
Shaded area no particle id
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IceCube effective area and angular resolution for
muons
further improvement expected using waveform info
Median angular reconstruction uncertainty 0.8?

• E-2 nm spectrum
• quality cuts and background suppression (atm m
  reduction by 106)

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Diffuse Fluxes - Predictions and Limits
Macro
Baikal
Amanda
IceCube Sensitivity after 3 years
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Point sources event rates
Flux equal to 3x current AMANDA limit dN/dE
10-6E-2/(cm2 sec GeV)
Atmospheric Neutrinos AGN (E-2) Sensitivity (E-2/(cm2 sec GeV))
All sky/year (after quality cuts) 100,000 -
Search bin/year 20 2300 -
3 year Nch gt 40 (E gt 7 TeV) 0.82 1370 2.4 x 10-9
Compared to AMANDA-II 7 times more PMT --gt 50
to 100 times more atmosph. neutrinos _at_ better
angular and energy resolution
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IceCube Digital Optical Module
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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

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• 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 lt 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 lt 2x10-10

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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
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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 (1010 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.

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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.
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Dark Freezer laboratory Test all optical
sensors for 2 weeks at temperatures -55C to
20C
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(No Transcript)
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PMT HV Calibration
C O U N T S
CHARGE
G A I N
Nominal HV Setting
VOLTAGE
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Final Acceptance Test Results

• In-Ice Noise Rate 1 kHz
• Time Resolution lt 3ns
• Noise Stability Monitor detected
• Synchrotron radiation from the SRC,
• Physical Sciences Lab, Wisconsin

Detection of Synchrotron across the street
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Triggering on Cosmic Rays
Single PE trigger
Local Coincidence triggering for DOMs with 1.5m
vertical separation
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Getting to the South Pole
A six hour flight from New Zealand to McMurdo
Station, via C-141 Starlifter
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A three hour flight from McMurdo to South Pole
Station, via C-130 Hercules
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Hose-reel with hose,built at Physical Sciences
Laboratory UW-Madison (Nov 2003)
Hose-reel atSouth Pole (Jan 2004)
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AMANDA
Deployment
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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

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