First Results from IceCube

Physics Motivation

Hardware Overview

Deployment

First Results

Conclusions & Future Plans

Spencer Klein, LBNLfor the IceCube Collaboration

See Paolo Desiati’s AMANDA talk

S. Klein, LBNL

USA (12)USA (12)

Europe (12)Europe (12)JapanJapan

New ZealandNew Zealand

• Alabama University, USA• Bartol Research Institute, Delaware, USA• Pennsylvania State University, USA• UC Berkeley, USA• UC Irvine, USA• Clark-Atlanta University, USA• Univ. of Maryland, USA

• Alabama University, USA• Bartol Research Institute, Delaware, USA• Pennsylvania State University, USA• UC Berkeley, USA• UC Irvine, 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• Universiteit Gent, Belgium• Humboldt Universität, Germany• Universität Mainz, Germany• DESY Zeuthen, Germany• Universität Dortmund, Germany

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

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

• Universität Wuppertal, Germany• Kalmar university, Sweden,• 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

The IceCube Collaboration

S. Klein, LBNL

Physics Motivation Search for cosmic-ray accelerators

Protons are bent in galactic magnetic fields

are produced by hadron accelerators

HE (>5*1013 eV) photons are absorbed by interaction with 30K microwave background photons --> e+e-

Study the High-Energy Universe ~100 GeV – 1019 eV

Cross section & effective area rise with energy, so a single detector can cover a very wide energy range

S. Klein, LBNL

Physics Topics Source searches

Active Galactic Nuclei Supernova remnants Gamma-Ray Bursts Calculations predict 1-10 /km3/year from many

source models Neutrino physics

Expect 100,000 atmospheric /year Cross-section measurements

Absorption in earth Decoherence Oscillations

Searches for supersymmetry, WIMPs, MeV from supernovae, monopoles, Q-balls….

Crab Nebula

Active Galactic Nucleus

S. Klein, LBNL

Detector Requirements

Need 1 km3 area for a good chance to see signals

Requires a natural material Ice or water

South Pole Ice has Long absorption length Shorter scattering length

Depth dependent Low dark noise rates

Ice model:Scattering vs. wavelength and depth

S. Klein, LBNL

Lessons from AMANDA AMANDA pioneered astronomy at the

South pole Deployed first OMs 1993/4

Observed atmospheric

Deep ice (> 1 km) has good optical qualities

Data transmission to surface nontrivial Paolo Desiati’s talk will present

AMANDA results

A muon inAMANDA

S. Klein, LBNL

1 gigaton instrumented volume 80 strings of 60 digital optical modules

1450-2450 m deep 17 m spacing

125 m hexagonal grid Each DOM is an autonomous data

collection unit IceTop air shower array

160 surface water tanks Each contains 2 DOMs

AMANDA

String 21

IceCube

1 string + 8 tanks deployed Jan. 2005

S. Klein, LBNL

, e and IceCube will distinguish , e and based on the event characteristics

--> produce long muon tracks Good angular resolution, limited energy resolution Atmospheric are a significant background to searches for extra-terrestrial

• Soft energy spectra --> may improve signal to noise ratio by optimizing for higher energy

e --> e produce EM showers Good energy resolution, poor angular resolution

Above ~1016 eVproduce ‘double-bang’ events One shower when the is created, another when it decays

S. Klein, LBNL

Eµ=6 PeV, 1000 hitsEµ=10 TeV, 90 hits

Simulated Events

S. Klein, LBNL

A e would appearas a single shower

n.b. c=300 m forE = 6 TeV

A simulated multi-Pev event

S. Klein, LBNL

Digital Optical Module

main board

LED flasher board

PMT base

25 cm PMT33 cm Benthosphere

Hardware

S. Klein, LBNL

Analog Front-End Want to measure arrival time of every photon 2 waveform digitizer systems

200-700 Megasamples/s, 10-bit switched capacitor array 3 parallel digitizers give 14 bits of dynamic

range 128 samples --> 400 nsec range Dual chips to minimize dead-time

40 Megasamples/s, 10-bit ADC 256 samples --> 6.4 s range

Self-triggered Also, ‘local-coincidence’ circuitry looks for hits in

nearby modules

An ATWD waveform

Time bin (3.3 ns)

S. Klein, LBNL

DOM Readout

Each DOM is a ‘mini-satellite’ FGPA + ARM7 CPU for control,

data compression… Packetized data is sent to surface Baseline data transmission

waveforms for local coincidence data Rate ~ 15-30 Hz

timing and charge info for isolated hits Rate ~ 700 Hz

‘Rapcal’ timing calibration maintains clock calibration to < 2 nsec

A ‘Main Board’

S. Klein, LBNL

Surface DAQ Trigger based on multiplicity &

topology (in a sliding time window) Selected data saved to tape High-priority data sent north over a

satellite link GPS clock for overall timing

S. Klein, LBNL

Amundsen-Scott South Pole station

South PoleDome (old station)

“Summer camp”

road to work

IceCube

Skiway

http://icecube.wisc.edu

AMANDA

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The drilling site in January, 2005

Hot-water drilling

Hose reel Drill tower

IceTop tanksHot water generator

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The 5 MW water heaterfor the hot water drill

(car-wash technology)

Hose Reel

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Each 2 m dia. IceTop tank contains two DOMs.

An IceTop tank

signals from IceTop DOMs

S. Klein, LBNL

Schedule & Logistics Can work December --> mid-February Logistics are a huge concern

Freight, power, … are expensive! Weather is always a factor

The new South-Pole station

S. Klein, LBNL

27.1, 10:08: Reached maximum depth of 2517 m28.1, 7:00: preparations for string installation start9:15: Started installation of the first DOM22:36: last DOM installed 12 min/DOM22:48: Start drop29.1, 1:31: String secured at depth of 2450.80 20:40: First communication to DOM

IceCube’s First String: January 28, 2005

S. Klein, LBNL

2 high-multiplicity muon events

Tim

e R

esid

ual (

ns)

Tim

e R

esid

ual (

ns)

Tim

e R

esid

ual (

ns)

Depth (m)

Depth (m)

S. Klein, LBNL

First Results from String 21

• Time calibration

• Muon reconstruction

• Timing verification with muons

• Timing and Energy measurement with LED flashers

• Coincidence events IceCube - IceTop

S. Klein, LBNL

Time Calibration

for 76 DOMs

Time IceTop

In-ice DOMs

IceTop

S. Klein, LBNL

Muon and Flasher Reconstruction

Observe Cherenkov radiation from charged particle tracks

Muons produce ~ km long tracks + hadronic shower at interaction point

EM cascades produce ~ point sources LED flashers are a surrogate for e

Reconstruct both with maximum likelihood techniques Use arrival times of all photons, as

determined from waveform information

~10m-long cascades, e neutral current

S. Klein, LBNL

Muon zenith angle distribution

S. Klein, LBNL

Timing studies with muons

The random and systematic time offsets from one DOM to the next are small, ≤ +/- 3ns

Re

sid

ual

Tim

ing

(n

s)

Sca

tteri

ng

(

1/m

)

S. Klein, LBNL

A flasher event

Equivalent to ~ 60 TeV e

Flasher

Color --> arrival time Circle size --> Amplitude

S. Klein, LBNL

Timing resolution from flashers

1.74 ns rms

All 60 DOMs

{Photon arrival time difference between DOM45 & 46

S. Klein, LBNL

Energy Measurement for flashers

Reconstruct energy of flash for each flashing DOM, using known position

Variation due to Ice models LED intensity Detector Response..

Good agreement across entire string

All LEDsSide LEDs450 LEDs~1/3 Intensity

S. Klein, LBNL

IceTop and in-ice coincidences

Some of the difference is due to shower curvature

S. Klein, LBNL

Conclusions & Outlook

IceCube will explore the high-energy sky. With a 1 km3 effective area, IceCube has the power to

observe extra-terrestrial neutrinos. We deployed our first string in January, 2005.

76 out of 76 DOMs are working well. Timing resolution is < 2 nsec

Next austral summer, we will deploy 8-12 more strings. Largest neutrino observatory in the world.

By 2010, we will have instrumented ~ 1 km3.

S. Klein, LBNL

Extras/Backup

IceCube reviewers – read no farther

S. Klein, LBNL

10” PMTHamatsu-70

S. Klein, LBNL

Muon Angular Resolution

Waveforminformationnot used.Will improveresolution for

high energies !

S. Klein, LBNL

Timing verification with light-flashers

Photons going up Photons going down

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