A kmA km33 Neutrino Telescope: Neutrino Telescope: IceCube at the South PoleIceCube at the South Pole

Howard Matis - LBNLHoward Matis - LBNL

for the IceCube Collaborationfor the IceCube Collaboration

SPIE Hawaii - August 2002SPIE Hawaii - August 2002 H. Matis – Lawrence Berkeley National LaboratoryH. Matis – Lawrence Berkeley National Laboratory 22

Neutrino AstronomyNeutrino Astronomymeasuring measuring ss by its µ by its µ

Stable particles: Stable particles: p, p,

Astrophysical Astrophysical SourcesSources

• GRB, AGN, Super GRB, AGN, Super NovaeNovae

• GZK (p +CMB GZK (p +CMB ))• Topological defectsTopological defects

BackgroundsBackgrounds• Atmospheric Atmospheric ’’ss• Atmospheric Atmospheric ’’ss

IceCube

Earth

Accelerator

Target

SPIE Hawaii - August 2002SPIE Hawaii - August 2002 H. Matis – Lawrence Berkeley National LaboratoryH. Matis – Lawrence Berkeley National Laboratory 33

IceCubeIceCube

1400 m

2400 m

South Pole

IceTop

Skiway IceCube is designed IceCube is designed to detect neutrinos of to detect neutrinos of all flavors at energies all flavors at energies from 10from 1077 eV (SN) to eV (SN) to 10102020 eV eV

80 Strings80 Strings 4800 PMT 4800 PMT Instrumented volume: Instrumented volume:

1 km1 km33

Depth: 1400 m to Depth: 1400 m to 2400m2400m

Amanda

SPIE Hawaii - August 2002SPIE Hawaii - August 2002 H. Matis – Lawrence Berkeley National LaboratoryH. Matis – Lawrence Berkeley National Laboratory 44

South PoleSouth Pole

Dark sector

AMANDA

IceCube

Dome

Skiway

SPIE Hawaii - August 2002SPIE Hawaii - August 2002 H. Matis – Lawrence Berkeley National LaboratoryH. Matis – Lawrence Berkeley National Laboratory 55

Detecting Detecting ss

ss interact in earth interact in earth Produce µ (follows Produce µ (follows

path of path of )) Detect Cherenkov Detect Cherenkov

light in ice with light in ice with phototubes buried in phototubes buried in the icethe ice

Detect upward µDetect upward µss

Ice filters downward Ice filters downward cosmic µcosmic µss

QuickTime™ and aGIF decompressorare needed to see this picture.

SPIE Hawaii - August 2002SPIE Hawaii - August 2002 H. Matis – Lawrence Berkeley National LaboratoryH. Matis – Lawrence Berkeley National Laboratory 66

1 Km

•Measure energy at the detector by counting the number of fired PMTs and the total light.

Eµ=10 TeV Eµ= 6 PeV

Simulated Simulated + N + N -- + X + X

SPIE Hawaii - August 2002SPIE Hawaii - August 2002 H. Matis – Lawrence Berkeley National LaboratoryH. Matis – Lawrence Berkeley National Laboratory 77

Other ReactionsOther Reactionse + N e- + X

•Electron Cascade•1 PeV ≈ 500 m diameter

PeVPeV (300 m)(300 m)

decays

+ N - + X

SPIE Hawaii - August 2002SPIE Hawaii - August 2002 H. Matis – Lawrence Berkeley National LaboratoryH. Matis – Lawrence Berkeley National Laboratory 88

IceCubeIceCubeStringString

OM Spacing: 17 m

HV andBase

Gel

Main Cable

Glass pressuresphere rated to

10,000 psiOuter diameter: 13”

60 optical sensors/string

photomultiplier

1400 m

2400 m

DOM

String

SPIE Hawaii - August 2002SPIE Hawaii - August 2002 H. Matis – Lawrence Berkeley National LaboratoryH. Matis – Lawrence Berkeley National Laboratory 99

Digital Optical Module - (DOM)Digital Optical Module - (DOM)

Photomultiplier

Self-triggers on each pulseSelf-triggers on each pulse Captures waveformsCaptures waveforms Time-stamps each pulseTime-stamps each pulse Digitizes waveformsDigitizes waveforms Performs feature extractionPerforms feature extraction Buffers dataBuffers data Responds to Surface DAQResponds to Surface DAQ Set PMT HV, threshold, Set PMT HV, threshold, etcetc

33 cm

DOM Board

SPIE Hawaii - August 2002SPIE Hawaii - August 2002 H. Matis – Lawrence Berkeley National LaboratoryH. Matis – Lawrence Berkeley National Laboratory 1010

Requirements for One ElementRequirements for One ElementDigital Optical Module (DOM)Digital Optical Module (DOM)

Time resolution:Time resolution: < 5 ns rms< 5 ns rms Waveform captureWaveform capture

> 250 MHz> 250 MHz for first 500 nsfor first 500 ns ~ 40 MHz~ 40 MHz for 5000 nsfor 5000 ns

Dynamic RangeDynamic Range > 200 PE / 15 ns> 200 PE / 15 ns > 2000 PE / 5000 ns> 2000 PE / 5000 ns

Dead-timeDead-time < 1%< 1% OM noise rate OM noise rate < 500 Hz< 500 Hz ((4040K in glass sphere)K in glass sphere)

1 to 10,000 photons that are incident over several µs 1 to 10,000 photons that are incident over several µs

High dynamic range waveform recordingHigh dynamic range waveform recording

SPIE Hawaii - August 2002SPIE Hawaii - August 2002 H. Matis – Lawrence Berkeley National LaboratoryH. Matis – Lawrence Berkeley National Laboratory 1212

Time Time Synch-Synch-

ronizing ronizing ModulesModules

DOM

Surface

tdown =tup=1/2(Tround-trip- t)

t

SPIE Hawaii - August 2002SPIE Hawaii - August 2002 H. Matis – Lawrence Berkeley National LaboratoryH. Matis – Lawrence Berkeley National Laboratory 1414

DAQ DAQ Network Network

ArchitectureArchitecture

McParland et. al. -- A Preliminary Proposal for the IceCube DAQ System Architecture -- DRAFT7

DOMPair20 kB/sec

StringProcessor

N x 20 kB/sec

.

All Hits -0.6 MB/sec

80 Strings

String Subsystem:60 DOMs

N pairs

Event LAN100 BaseTTotal traffic: 1.6 MB/secStringCoincidenceMessagesGlobalTriggerEvent Triggers /Lookback Requests forall Strings - 0.8 MB/sec

EventBuilderBuilt events ~ 1 MB/sec(all event builders)

SAN(NetworkDisk Storage)

"DOMHUB"

Lookback RequestsString CoincidenceMessages - 170 kB/secFulfill Lookback Messages 0.6 MB/sec FulfillLookbackMessages

Online LAN100 BaseTTotal traffic: 1MB/sec

Proposed IceCube DAQ Network Architecture

String LAN100 BaseTTotal traffic: 0.6 MB/sec

OfflineDataHandlingTapeSatellite

String -Electronics in the ice Global

Timing

SPIE Hawaii - August 2002SPIE Hawaii - August 2002 H. Matis – Lawrence Berkeley National LaboratoryH. Matis – Lawrence Berkeley National Laboratory 1515

AMANDA String 18AMANDA String 18

Springboard for Springboard for transition to IceCubetransition to IceCube

41 DOMs deployed in 41 DOMs deployed in 99/00 season; 37 99/00 season; 37 operationaloperational

Test bed: download Test bed: download new code into icenew code into ice

Communicate and Communicate and program in North program in North AmericaAmerica

SPIE Hawaii - August 2002SPIE Hawaii - August 2002 H. Matis – Lawrence Berkeley National LaboratoryH. Matis – Lawrence Berkeley National Laboratory 1616

String 18 DOM BoardString 18 DOM Board

Oscillator

SPIE Hawaii - August 2002SPIE Hawaii - August 2002 H. Matis – Lawrence Berkeley National LaboratoryH. Matis – Lawrence Berkeley National Laboratory 1717

Digital ATWD WaveformsDigital ATWD WaveformsSingle PhotonADC Spectra

Complex Waveform@600 MHz

Time

ADC Charge

Hi Gain

Low Gain

No Gain

Clock

“Slow” ADC

•ATWD Channels 1 - 4: 1.7 ns/sample for 217 ns•ADC: 60 ns/sample for 7.7 s

“Bucket”

“Bucket”

“Bucket”

“Bucket”

“Bucket”

Digitalization @ ~ 600 Hz

SPIE Hawaii - August 2002SPIE Hawaii - August 2002 H. Matis – Lawrence Berkeley National LaboratoryH. Matis – Lawrence Berkeley National Laboratory 1818

Timing with “Phone Wire” to few nsTiming with “Phone Wire” to few ns

Transit time for 2.5 km twisted Transit time for 2.5 km twisted pair: ~12 pair: ~12 ss

Rise-time after propagation ~ 2 Rise-time after propagation ~ 2 s (~1/t)s (~1/t)

Use a bipolar “Time-Mark” Use a bipolar “Time-Mark” signal pulsesignal pulse

Digitize time-mark pulse @ 20 Digitize time-mark pulse @ 20 MHz, 10-bit MHz, 10-bit

Fit leading edge & baseline : Fit leading edge & baseline : 3.5 ns rms3.5 ns rms

SPIE Hawaii - August 2002SPIE Hawaii - August 2002 H. Matis – Lawrence Berkeley National LaboratoryH. Matis – Lawrence Berkeley National Laboratory 1919

Timing Timing with µwith µss

T (DOMN)

T (DOMN+1)

T = T (DOMN) - T (DOMN+1)

Two clear components:

• random coincidences (flat)

• correlated light (peak at ~ 0)

12 m

t - ns

SPIE Hawaii - August 2002SPIE Hawaii - August 2002 H. Matis – Lawrence Berkeley National LaboratoryH. Matis – Lawrence Berkeley National Laboratory 2020

Reconstructed Reconstructed Event Event

• Only first hit in each OM shown• Down flow of light• No “early photons”• Late hits consistent with:

• light scattering, or • a second ?

•Down going

SPIE Hawaii - August 2002SPIE Hawaii - August 2002 H. Matis – Lawrence Berkeley National LaboratoryH. Matis – Lawrence Berkeley National Laboratory 2121

String 18 PerformanceString 18 Performance

Timing: Timing: 3.5 ns rms3.5 ns rms (very stable)(very stable) SPE spectrum:SPE spectrum: as expectedas expected PMT Gain Drift:PMT Gain Drift: <<0.2 %/week<<0.2 %/week LED Beacons:LED Beacons: ~8 ns rms~8 ns rms (ice optics)(ice optics) Down going Down going :: observedobserved µ waveforms:µ waveforms: ~15%~15% have > 1 “hit” have > 1 “hit”

SPIE Hawaii - August 2002SPIE Hawaii - August 2002 H. Matis – Lawrence Berkeley National LaboratoryH. Matis – Lawrence Berkeley National Laboratory 2222

SummarySummary IceCube – New detector under development to explore IceCube – New detector under development to explore

astrophysical astrophysical ss

Decentralized timing with digital technologyDecentralized timing with digital technology Measure full waveformMeasure full waveform Provides more information for reconstructionProvides more information for reconstruction More detail for physics discoveryMore detail for physics discovery Feature extraction - less data to record and transmitFeature extraction - less data to record and transmit

Can synchronize separate and remote elements to Can synchronize separate and remote elements to several nsseveral ns

Fully functional prototypes tested with muons in AMANDAFully functional prototypes tested with muons in AMANDA Prototypes meet or exceed IceCube requirementsPrototypes meet or exceed IceCube requirements

SPIE Hawaii - August 2002SPIE Hawaii - August 2002 H. Matis – Lawrence Berkeley National LaboratoryH. Matis – Lawrence Berkeley National Laboratory 2323

Institutions: 11 US, 9 European, 1 Japanese and 1 Venezuelan;

1. Bartol Research Institute, University of Delaware (*)2. BUGH Wuppertal, Germany (*)3. Universite Libre de Bruxelles, Brussels, Belgium (*)4. CTSPS, Clark-Atlanta University, Atlanta, USA5. DESY-Zeuthen, Zeuthen, Germany (*)6. Institute for Advanced Study, Princeton, USA7. Lawrence Berkeley National Laboratory, Berkeley, USA (*)8. Department of Physics, Southern University and A\&M College, Baton Rouge, LA, USA9. Dept. of Physics, UC Berkeley, USA (*)10. Institute of Physics, University of Mainz, Mainz, Germany (*)11. University of Mons-Hainaut, Mons, Belgium (*)12. Dept. of Physics and Astronomy, University of Pennsylvania, Philadelphia, USA (*)13. Dept. of Astronomy, Dept. of Physics, SSEC, University of Wisconsin, Madison, USA (*)14. Physics Department, University of Wisconsin, River Falls, USA (*)15. Division of High Energy Physics, Uppsala University, Uppsala, Sweden (*)16. Dept. of Physics, Stockholm University, Stockholm, Sweden (*)17. Dept. of Physics, University of Alabama, USA18. Vrije Universiteit Brussel, Brussel, Belgium (*)19. Chiba University, Japan20. Dept. of Astrophysics, Imperial College, UK21. Dept. of Physics, University of Maryland, USA22. Universidad Simon Bolivar, Caracas, Venezuela (*) also in AMANDA

IceCube CollaborationIceCube Collaboration

SPIE Hawaii - August 2002SPIE Hawaii - August 2002 H. Matis – Lawrence Berkeley National LaboratoryH. Matis – Lawrence Berkeley National Laboratory 2424

The EndThe End