The Status of IceCubeMark Krasberg

University of Wisconsin-Madison

RICH 2004 Conference, Playa del Carmen, Mexico

Dec 3, 2004

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IceCube – a next generation observatory a cubic kilometer 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 of photoelectrons • entire waveform read out

Expected performance wrt AMANDA• increased effective area/volume• superior angular resolution • superior energy resolution

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PMT noise: ~1 kHzOptical Module

“Up-going”(from Northern sky)

“Down-going”(from Southern sky)

AMANDA-II19 strings677 OMs

Trigger rate: 80 HzData years: >=2000

PMT looking downward

Measurements:►in-situ light sources►atmospheric muons

Average optical ice parameters:λabs ~ 110 m @ 400 nm

λsca_eff ~ 20 m @ 400 nm

bubbles

dust

A

dust

ice

Scattering Absorption

Polar Ice Optical Properties

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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 ConceptDeep 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) ’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

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Amundsen-Scott South Pole Research Station

8 + N + N + + XX

CC muon neutrino muon neutrinointeractioninteraction

tracktrack

AMANDA

muon

event

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Track Reconstruction in Low Noise Environment

• 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 AMANDA

IceCube

IceTop

1200 m

Energy ReconstructionSmall 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.

Eµ=6 PeV, 1000 hitsEµ=10 TeV, 90 hits

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1 PeV (300m)

decays

- flavors and energy ranges

e

Log(energy/eV)12 18156 219

e

• Filled area: particle id, direction, energy• Shaded area: no particle id

pulse

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IceCube effective area and angular resolutionfor muons

Galactic center

E-2 spectrum

quality cuts and background suppression (atm reduction by ~106)

further improvement expected

using waveform info

Median angular reconstruction

uncertainty ~ 0.8

MacroBaikalAmanda

Diffuse Fluxes - Predictions and Limits

IceCubeSensitivity after 3 years

Point sources: event rates

Atmospheric

NeutrinosAGN* (E-2)

Sensitivity(E-2/(cm2 sec GeV))

All sky/year

(after quality cuts)100,000 -

Search bin/year 20 2300 -

3 year: Nch > 40

(E > 7 TeV)0.82 1370 2.4 x 10-9

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

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IceCube Digital Optical Module

Digital Optical Module • records timestamps

• digitizes waveforms

• transmits to surface at

request via digital

communications

•can do local coincidence

triggering

optical sensor10 inch Hamamatsu R-7081

mu metal cage

PMT

penetrator HV board

flasher board

DOMmain board

pressure sphere

optical gel

delay board • design requirement

Noise rate ~1 kHz• SN monitoring within

our Galaxy

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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

waveformssystem time stamp resolution 7 ns wrt

master clock

FPGA (Excalibur/Altera) reads out the ATWD

handles communications time stamps

waveformssystem time stamp resolution 7 ns wrt

master clock

oscillator (Corning Frequency Ctl) running at 20 MHz

maintains f/f < 2x10-10

2 four-channel ATWDsAnalog Transient Waveform

Digitizerslow-power ASICs

recording at 300 MHz over first 0.5s

signal complexity at the start of event

2 four-channel ATWDsAnalog Transient Waveform

Digitizerslow-power ASICs

recording at 300 MHz over first 0.5s

signal complexity at the start of event

Dead time < 1%

Dynamic range - 200 p.e./15 ns- 2000 p.e./5 s

energy measurement (TeV – PeV)

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DOM Waveform Capture

t

• Altera Excalibur ARM922t P+ 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 s wide).

High Gain

Medium Gain

Low Gain

400 ns window

Calibration

1. Calibration of sensors in the lab at temperatures between -20 and -55C (deep ice: -18C to -42C)

2. LED Flashers on each module, 12 LEDs, in 6 directions and 2 angles (10^10 photons)

3. Special “high energy” lasers

4. Timing calibration is feature of DOM: 5 nsec

5. IceTop: High level cross calibration of muon tracks with air showers.

6. 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 weeksat temperatures -55°C to +20°C

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PMT HV Calibration

C

O

U

N

T

S

CHARGE

VOLTAGE

G

A

I

N

Nominal HV Setting

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Final Acceptance Test Results

Detection of Synchrotron across the street

• In-Ice Noise Rate ~ 1 kHz

• Time Resolution < 3ns

• Noise Stability Monitor detected

Synchrotron radiation from the SRC,

Physical Sciences Lab, Wisconsin

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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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A six hour flight from New Zealand to McMurdo Station, via C-141 “Starlifter”A six hour flight from New Zealand to McMurdo Station, via C-141 “Starlifter”

Getting to the South PoleGetting to the South Pole

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

29Hose-reel at

South Pole (Jan 2004)

Hose-reel with hose,built at Physical Sciences Laboratory

UW-Madison (Nov 2003)

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SummaryIceCube 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

• Data taking begins early next year

IceCube strings IceTop tanks4 8 Jan 200516 32 Jan 200632 64 Jan 200750 100 Jan 200868 136 Jan 200980 160 Jan 2010

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IceCube drill camp construction site of the first hole,

Nov 25, 2004

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USA (12)USA (12)

Europe (12)Europe (12)

VenezuelaVenezuela

JapanJapan

New ZealandNew 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• Universität Dortmund, Germany

• Universite Libre de Bruxelles, Belgium• Vrije Universiteit Brussel, Belgium• Université de Mons-Hainaut, Belgium• Universität Mainz, Germany• DESY-Zeuthen, Germany• Universität Dortmund, Germany

• Universität Wuppertal, Germany• Uppsala university, Sweden• Stockholm university, Sweden• Imperial College, London, UK• Oxford university, UK• Utrecht,university, Netherlands

• Universität Wuppertal, Germany• Uppsala university, Sweden• Stockholm university, Sweden• Imperial College, London, UK• Oxford university, UK• Utrecht,university, Netherlands

• Chiba university, Japan• University of Canterbury, Christchurch, NZ

• Chiba university, Japan• University of Canterbury, Christchurch, NZ

ANTARCTICA

• Universidad Simon Bolivar, Caracas, Venezuela