1. Introduction2. IceCube Detector3. Neutrino Detection Principles4. Status of the Construction and Performance5. Summary

IceCubeneutrino telescope@SouthPole

- a new window on the universe

Joanna Kiryluk LBNL/UC Berkeley

UHE

Cosmic Rays

€

p+ γ → Δ → π + n→ ...GZK cutoffGreisen, ZatsepinAnd Kuzmin (1966)

QuickTime™ and aTIFF (Uncompressed) decompressor

are needed to see this picture.

What’s the origin of Cosmic Rays with E up to 1020 eV ?The puzzle unresolved almost a century after CR discovery

?SNR

- do not point back to the source

protons: directions scrambled by magnetic

fields -rays : straight-line

propagation

Multi-Messenger AstronomyWhere do UHE cosmic rays come from?

protons, -rays & neutrinos as probes of the high-energy Universe

- do not point back to the source

but reprocessed in the sources (difficult to prove that they are associate with CR); extragalactic backgrounds absorb E>TeV

Multi-Messenger AstronomyWhere do UHE cosmic rays come from?

protons, -rays & neutrinos as probes of the high-energy Universe

protons: directions scrambled by magnetic

fields -rays : straight-line

propagation

Neutrinos:Neutrinos: straight-line propagation, unabsorbed, but difficult to detect

Expected n flux from galactic point sources, example SNR: RXJ 1713-3946

Christian Stegmann et al. , J.Phys.Conf.Serv.60 (2007) 243

€

p+ γ → n + π +

€

π → μ+υμ

→ {e + υ μ + υ e} + υ μ

cosmic rays interact with the microwave

background

cosmic rays disappear, neutrinos appear

NeutrinosfromGZKinteractions

Expect ~ 1 event per km2 per year

GZK neutrinos - very low but guaranteed flux (GZK CRs exist!)

(Ultra-) high-energy neutrino detectors

Neutrino telescopes:Primarily aimed at > TeV μ, e.g. IceCube /AMANDA, Antares … Also sensitive to PeV, EeV , but limited area

New directions with effort to detect:Giant air showers detectors sensitive to ~EeV e.g. AugerRadio detection - threshold in EeV range , e.g. Anita

Extraterrestrial neutrinos - discovery potential!

The only confirmed extraterrestrial low energy neutrino sources detected so far are the Sun and the supernova SN1987A

USA: Bartol Research Institute, Delaware Pennsylvania State University UC Berkeley UC Irvine Clark-Atlanta University University of Maryland IAS, Princeton University of Wisconsin-Madison University of Wisconsin-River Falls Lawrence Berkeley National Lab. University of Kansas Southern University and A&M

College, Baton RougeUniversity of Alaska, Anchorage

Sweden: Uppsala Universitet Stockholm Universitet

UK: Imperial College,

London Oxford University

Netherlands: Utrecht University Belgium:

Université Libre de Bruxelles

Vrije Universiteit Brussel Universiteit Gent Université de Mons-Hainaut

Germany: Universität Mainz DESY-Zeuthen Universität Dortmund Universität Wuppertal Universität Berlin MPI Heidelberg RWTH Aachen

Japan: Chiba university

New Zealand: University of

Canterbury

THE ICECUBE COLLABORATION

33 institutions, ~250 members http://icecube.wisc.edu

ANTARCTICAAmundsen-Scott Station

Science potential with IceCube is vast:

Neutrino point source search (μ Diffuse searches ( e, μ and more sensitive if there are more sources

IceCube physics topics

Atmospheric neutrinos Cosmic Ray (C.R.) composition Supernova (SN) Gamma Ray Bursts Search for exotic particles and new physics.

QuickTime™ and aTIFF (Uncompressed) decompressor

are needed to see this picture.

http://www.sciencemag.org/content/vol315/issue5808

Vol 315 (2007)

The IceCube Detector

Counting House

1450 m

2450 m

AMANDA

IceTop Surface air shower array

InIce 70+ strings, each with 60

digital optical modules (DOM)

17 m between modules

125 m string separation

Instrumenting 1km3 of Antarctic Iceto detect extraterrestrial neutrinos

IceCube will detect neutrinos of all flavors at energies from 1011 eV to 1020 eV

Digital Optical Module (DOM)

DOM - a complete data acquisition system: - internal digitization and time stamping the photonic signals from the PMT- can perform PMT gain and time calibration- transmitting digital data to the surface

PMT

MainBoard

Main Board (most of electronics)- PMT output collected with fast waveform digitizer chips that sample the signal 128 times at 200-700 MSPS - PMT signal is fed into 3 parallel 10-bit ADC with a nominal gain ratios 0.25:2:16. Combined they provide wide dynamic range from single p.e. to thousands p.e.

Time Resolution from LED flashers

Method: flash an LED on a DOM and measure the arrival time of light reaching a nearby DOM

RMS variation of time delay measured with flashers for 59 DOM pairs on one string.

For most of the DOMs resolution better than 2 ns

DOM 51

DOM 52

DOM 53

DOM 54

Photon arrival time delay at DOM 52 when DOM 53 is flashing.

Muon neutrino Electron neutrino

Phototubes

(km long) Track:

+ increased detection volume

+ μ points along μ, i.e. to source

- cosmic ray μ background

- ok energy measured

Cascade: e-m or hadronic showers -must be in detector- μ background (brems’ng)- limited pointing capability + good energy measurement

Neutrinos: How do we see them?

Energy Res. : log(E)~0.3Angular Res.: 0.8 -2 deg

Neutrinos Signature (Simulations)

QuickTime™ et undécompresseur TIFF (non compressé)

sont requis pour visionner cette image.

E = 375 TeV

Energy Res. log(E)~0.1-0.2Poor Angular Resolution

QuickTime™ et undécompresseur TIFF (non compressé)

sont requis pour visionner cette image.300m

+N+...

+hadrons

Muon neutrino Electron neutrino Tau neutrino

a) Eµ=10 TeV ~ 90 hits

b) Eµ=6 PeV ~1000 hits

E = 10 PeV

Double-bang signature above ~ 1 PeVVery low backgroundPointing capability

E ~ dE/dx, E> 1 TeV

Origin of the neutrinos observed in the detector

M.Kowalski [astro-ph/0505506]

atmospheric neutrinos (mostly μ) dN/dE~E-3.7

neutrinos from charm decayIn the atmosphere dN/dE~ E-2.8

astrophysical neutrinos dN/dE~E-2.0 (model)

signal

Extraterrestrial Neutrinos: Signals and backgrounds

Low energy: Distinguish: - μ (CR vs ) by their direction- (atmospheric vs extrater.) by energy

Above 105 TeV - small μ and bg produced in CR interactions with the Earth atmosphere.

Distinguish flavor by their topology

High energy:

Neutrinos (all flavors) interact in(or close to) the detector via:Muon channel:

Cascade channel:

€

e(τ ) + N → e(τ ) + X (CC)ν e(μ ,τ ) + N →ν e(μ ,τ ) + X (NC)

€

μ + N → μ + X (CC)

AMANDA

IceCube

Skiway

Amundsen-Scott South Pole Station

Geographic South Pole

IceCube at the South Pole

Drill Site Counting House

Getting there is half the fun

New C-17 Old C-141 (photo by RGS)

Transportation upgrades to Antartica….

Schedule and Logistics

The new South-Pole station

Can work from December to mid-February Logistics are a huge concern Power - expensive! 3 winterover scientists operate and maintain instrument during winter Weather is always a factor

Field team deals very well with issues and harsh conditions

Hotwater drill system

Drill tower

Hose reel

DOMs

Hole Drilling

Design goal: 40 hours to drill a hole

36 h

Successfully used for three holes. Expected to save about 2 holesper season.

2007: Independent firn drillD

ep

th (

m)

Time

2500 m deep, 60 cm dia. holes 5 Megawatt hot water drill Speeds to 2.2 m/minute

IceCube Deployments to Date AMANDA

21

3029

40

50

3938

49

59

4647

48

5857

6667

74

65

73

78

56

72

2004-2005

1 string deployedFirst dataastro-ph/0604450

2005-2006

8 string deployed

2006-2007

13 strings deployed

1+8+13 = 22 strings to dateGoal >=14 strings/season

Completion by 2011.

More than 25 % of full detector installed.

1424 sensors deployed, and 1403 sensors (98.5%) are commissioned and being used

Comparison to AMANDA-II: 85 of 677 sensors (12.5%) are not usable for technical reasons

April 29 2007 (commissioning)

IceDust layer (low rate)

2007 13-strings Deployment Physics Run - started May 2007 Updated DAQ, triggers, monitoring system

1450m 2450m 0 50m

Measurements: in-situ light sources, atmospheric muons and Dust Loggers (records dust layers with cm resolution):

Ice Properties: scattering and absorption

Average optical ice parameters:

Dust Logger signal

depth (m)

depth (m)D

OM

Occ

upan

cy

abs~110m@400nmsca~ 20m@400 nm

Scattering length varies from 6 to 30m depending on depth and location of dust layers (deposited by e.g. volcanic events over past thousands of years)

Understanding ice properties - key to modeling IceCube

Probability a DOM is hit in evts that have >7 hits on a string

QuickTime™ and aTIFF (Uncompressed) decompressor

are needed to see this picture.

Dust Logger

QuickTime™ and aH.264 decompressor

are needed to see this picture.

Bubble Camera - 2007 deployment

DOM 60

Weight Stack

Sphere 1

Sphere 2

String 57

Particle (μ) Tracking

Charged particles emit Cherenkov radiation angle = Cos-1(1/n) = 410

The photons scatter (L ~ 25 m) Some (<10-6) photons are observed in photodetectors We measure points 0-30 meters from the μ track Angular resolution < 10 for long tracks

μNoise

€

μ + N → μ + X

bremsstrahlung

pair-creation

e+e-

πphoto-nuclear

μ tracks lose energy by emitting , e+e- pairs and hadronic interactions (via virtual )

DOM

Atmospheric muon neutrinos in 2006 2006 data: 90 days with 9 stringsData selection done online at S. Pole and transferred by satellite North

Neutrino-induced muon candidate

Dust layer

IC-9strings (first) analysis: Atmospheric muon neutrinos in 2006

Reconstructed Zenith Angle (deg)

Contamination at the horizon likely due to mis-reconstructed events (single shower) as being below the horizon.

After cuts: 234 events measured (211 expected from atm. MC) Reconstructed direction

Reconstructed Azimuth Angle (deg)

Horizon

arXiv:0705.1781 [astro-ph]

Event rate: 610 Hz Raw data: 180 GB/day Uptime to date: 92% Events recorded by June 28, 2007 1.65 x 10^9 Continuous data taking …

Sufficient data to observe (diffuse) non-atmospheric neutrinos?

IC-22 run statusMay 23, 2007 - start of IceCube science run

Downgoing muons (background) Azimuth distribution illustrates

detector response.

String Commissioning

pDAQ IC36+Commissioning(95%)

Calibration(Geometry, DOMs)

P&F IC36+Commissioning

Dec Jan Feb Mar April

IC22 Science run IC36+ Science run

IC 36+ verification

FinishLatecomers

IC22 IC36+ Schedule

Current status: Ready to go….winterovers arrive on ice Oct 22!!Bulk of drillers arrive on Oct 31

Future Plans Above ~ 1016 eV, the expected rates in IceCube are small

A ~100 km3 detector is needed to see GZK Protons and have limited range. Only probe sensitive to ‘EHE universe’ > 50 megaparsecs away

Coherent radio and/or acoustic detection of EHE showers may allow for an affordable detector

Summary IceCube construction is well underway

- More than 25% complete.- Completed detector in 2011.

Physics analysis underway.IceCube IC-9 atmospheric muon neutrino resultsIC-22 analyses on-going

Stay tuned!

ANITA

ANITAGondola &

Payload

Antenna array

Overall height ~8m

Solarpanels

Antarctic Impulsive Transient Antenna Experiment

searching for GZK neutrinos with radio

detection in Antarctic iceneutrino

Cascade: ~10m length

air

Ice- radio transparent medium

RFCherenkov

Utilizes Askaryan effect

STATUS: 35 day flight this season 2006/7

~15 days of good data - Haven’t unblinded yet

- Might see a GZK neutrino, if luckyPayload was crunched on landing

Next flight in 2008/9

ARIANNA concept

100 x 100 station array, ~1/2 Teraton

~300m

Ross Ice Shelf, Antarctica

Sensitivity and limits

S. Barwick

ANITA sensitivity, 45 days total:~5 to 30 GZK neutrinos

IceCube: high energy cascades ~1.5-3 GZK events in 3 years

Oscar Blanch-Bigas

Neutrino fluxes - upper limits

Supernova Monitor

Amanda-II

IceCube

0 5 10 sec

Count rates

LMC

AMANDA II:95% of Galaxy

IceCube:Milky Way + LMC

msec time resolution

You are here

Data Acquisition and Trigger

“Full” DAQ software & triggerSelect time regions of interest using

multiplicity, topologyEvents == time windowCollect data for these windows

Data filtering (muon, cascade)Reconstruct eventsSelect interesting events for satellite

transmission

Monitoring, calibration, logging, control functions,…

Master Clock

Distribution

InIce