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ANTARES : A deep-sea 0.1 km² neutrino telescope. Greg Hallewell – CPP Marseille Representing the Antares Collaboration. RICH2002 Workshop on Ring Imaging Cerenkov Detectors, Pylos, Greece, June 5-9, 2002. CPPM, Marseille DSM/DAPNIA/CEA, Saclay C.O.M. Marseille IFREMER, Toulon/Brest

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Antares a deep sea 0 1 km neutrino telescope

ANTARES : A deep-sea 0.1 km² neutrino telescope

Greg Hallewell – CPP Marseille

Representing the Antares Collaboration

RICH2002 Workshop on Ring Imaging Cerenkov Detectors, Pylos, Greece, June 5-9, 2002


Antares collaboration

  • CPPM, Marseille

  • DSM/DAPNIA/CEA, Saclay

  • C.O.M. Marseille

  • IFREMER, Toulon/Brest

  • LAM, Marseille

  • IReS, Strasbourg

  • Univ. de H.-A., Mulhouse

  • ISITV, Toulon

  • Observatoire de la Côte d’Azur

  • University of Bari

  • University of Bologna

  • University of Catania

  • LNS – Catania

  • University of Rome

  • University of Genova

ANTARES Collaboration

  • NIKHEF, Amsterdam

  • University of Sheffield

  • ITEP, Moscow

  • IFIC, Valencia

  • Universitat Erlangen


Contents

Contents

  • Detector Overview

  • Detector Principal Components

  • Site Selected and Ocean Backgrounds

  • 40K, bioluminescence, light absorption

  • 4) “Demonstrator” Line

  • 7 PMTs, m hyperbolic reconstruction

  • 5) Time and Position Calibration

  • m reconstruction from PM signals with arrival times known to ~1 ns

  • acoustic transponder net, LED and laser beacons

  • 6) Sea Instrumentation Line

  • current profile, salinity, light absorption, P,T, sound velocimeter

  • 7) “Sector” Line Deployment

  • 8) Conculsions


Antares a deep sea 0 1 km neutrino telescope

(1.1) Detection Principle

Lattice of 900 PMTs in “Optical Modules”

m track direction from arrival time of light

Neutrino direction:       0.7o / E0.6(TeV)

m energy from energy loss and range

Typ. 1g per PMT 40m from m trajectory

Cerenkov

light isochrone

in seawater

muon

ANTARESDetector

interaction

A 0.1km2 detector should record ~ 1-2000 medium energy cosmic neutrinosper year (En > 300 GeV).

neutrino


Antares a deep sea 0 1 km neutrino telescope

(1.2)Scientific Motivation

Medium Energy

(10 GeV < E < 1 TeV)

Low Energy

(10 GeV < E < 100 GeV)

High Energy

(E> 1 TeV)

neutralino search

(signal from annihilating

WIMPs in the Earth,

the Sun and the Galaxy)

 from galactic and extra-galactic sources (x-ray binaries, micro-quasars, SNR, AGN, GRB)

 oscillations

(observation of first

oscillation minimum

from atmospheric )

+Oceanography

- measurements of oceanographic parameters of the deep sea

- studies of bioluminescence


0 1 km detector expected performance

Energy resolution

Angular resolution

0.1 km² Detector : Expected performance

  • Including effects of reconstruction and selection, PMT TTS, positioning, timing calibration accuracy and scattering.

  • Below ~10 TeVangular error is dominated by - physical angle.

  • Above ~10 TeV angular accuracy is better than 0.4° (reconstruction error).

  • E/E  3 (E 1 TeV)

  • Below E ~ 100 GeV energy estimation via muon range measurement.


Antares a deep sea 0 1 km neutrino telescope

  • 10 lines of 90 PMTs

  • 6 sectors/line (350m)

  • 5 storeys/sector(60m)

  • 3 PMTs/storey(12m)

Time calibrationLED Beacon

(1 / sector)

Optical Moduletriplet

Local electronics

Hydrophone

(1 / sector)

ANTARES 0.1km2 detector

2400m

40 km cable

to shore

12 m

350 m

100 m

Junction

box

60 m

Readout cables


Antares a deep sea 0 1 km neutrino telescope

String Control/Power Module:

- string power supplies

- data acquisition: 6 sectors  DWDM  6x1Gb/s on 1 fibre

Interlink cable,

- wet-mateable connector: 4 optofibres+ 2 power conductors

Bottom String Structure

- acoustic string release, acoustic positioning transponder

(2) Principal Components: A Detector Line

Buoy

Electro-mechanical Cable

- mechanical support (kevlar core)

with optical fibres and power conductors

90 PMTs/line

6 sectors of

5 storeys of

3PMTs

LED Beacon (4 per line)

  • 3 Optical Modules/storey

  • - 10” PMT, active base, LED internal calibration system

  • 1 Local Control Module;

  • “ARS” front end ASIC (amplitude, 1GHz time sampling)/PMT;

  • Tiltmeter (line shape in current) & compass (line torque)

12m

Master Local Control Module:

- acoustic positioning (1 hydrophone / sector)

- data acquisition: 5 storeys  sector ethernet 1Gb/s

100m

Sea bed


2 1 principal components optical module pm

Quantum Efficiency

Latt(Sphere)

(LoBoro): cm

Latt(Gel): cm

(2.1) Principal Components: Optical Module & PM

LED pulser

Optical gel

Photomultipler: 10” Hamamatsu R7081-20

Sensitive area > 500 cm2;

14 stages; 2.108 Gain @ 2500V;

Transit Time:

typ 60ns @ 1750V (–2.5ns/100V)

(Regularly Measured by LED pulser on each tube)

Transit Time Spread:

s  1.3 ns(spec.):V fixed;

Dark Count Rate (0.3 pe equ. Thr.): < 10kHz;

Pulse Shape:

Rise Time < 5 ns, FWHM < 12 ns

Active (C-W) PMT

Base (ISEG)

Glass sphere (Nautilus)

Mu metal magnetic shield


Antares a deep sea 0 1 km neutrino telescope

Some Detector Specificatons

Cerenkov signature:

Timing of cone arrival at PMTs on strings: hyperbolic fit

PMT positions need to be known to ~20 cm (1 ns in seawater)

# OM hits depends on range of muon

Detector Positioning Resolution

Hits to s <1 ns to be small compared with dispersive limits

in seawater of ~ 1.6 ns over ~ 40 m optical path length

achieved by:

acoustic transponder net: string profile in undersea current,

inclinometers (pitch, yaw) & compasses

(heading: OM rotation angle around string ): (1 per “storey”)

Timing Resolution on OM

LED Pulser in each OM, LED & Laser beacons:Goal < 0.5 ns


2 3 ars timing resolution may 02

Timing Resolution: electronic signals directly into ARS

Timing Resolution: attenuated laser signals  OM ARS

(2.3) ARS Timing Resolution (May ’02)


3 the antares site

(3) The ANTARES Site

Antares Site:

40Km SE Toulon

(42º50’N, 6º10’E)

Depth 2400m

Shore Base

La Seyne-sur-Mer

40 km

Submarine cable

-2400m


Antares a deep sea 0 1 km neutrino telescope

Line connections

Victor (ROV)

1

2

6

5

3

4

10

9

8

7

13

14

11

12

(3.2) Site: Sea Floor Layout, Vehicle Resources

Site inspection:

“Cyana”

(Manned Submersible)

Line sea floor

configuration

Wet-Mateable Connector (@250 bar H2O)

At Line Sea Anchor

Submarine cable:

ALCATEL


3 4 water optical properties transparency

Variable distance between

LED and PMT “ascenseur”

(3.4) Water optical properties: Transparency

Need in-situ on line monitoring (instrumentation line)


3 5 water properties optical backgrounds

(3.5) Water Properties: Optical Backgrounds

  • Cerenkov Light:

  • from Atmospheric (Downgoing)m’s

  • (~400g cm-1: 300<l<600 nm)

  • ( <Em> ~350 GeV:mrate 10-30 Hz)

  • (106 * rate of upgoingmfromn)

  • (2) Sea Optical background:

  • ~ 60 kHz on 10” PMT mainly 40K

  • Bioluminescence

  • bursts(o~MHz), locally-correlated (typ 1 storey, 3 PMTs)

  • ~ few % of the time

  • + Bottom Current Dependent

  • Bottom Currents Measured

  • typ. < 5% dead time/ PMT


4 full demonstrator line 98 00

  • December 98 : successful undersea electrical connection test of detector anchor performed at 2400m depth by IFREMER submarine vehicle “Nautile” (ex-Titanic expeditions)

(4) Full Demonstrator Line (’98-’00)

  • First (350m) line equipped with 16 pairs of Glass Spheres

    • Summer 98 :successful deployment test at 2300m depth performed with Dynamical Positioning ship

    • December 99-June 00 :demonstrator equipped with 7 PMTs + acoustic positioning system linked to shore station by electro-optical cable

    • 50,000 atmospheric m’s reconstructed


4 1 muons on demonstrator line

(4.1) Muons on “Demonstrator line”

  • 50,000 events with 7-fold coincidences

  • (>1300 reconstructed events per day)

  • Zenith from 4 par. Hyperbolic fit of depth vs. PMT signal timestamp

  • 40K hits filtered out by software

  • MC agrees with data (multimuons, ghosts)

No reconstructed

events q < 45º


5 1 40 60 khz acoustic positioning system

1 of 3 rangemeters

Devices

Accuracy ()

Inter-rangemeter

~1 cm

5cm

Inter-Transponder

~ 1 cm

Rang.-Transponder

 3 cm

Time (min)

(5.1) 40-60 kHz Acoustic positioning system

4 transponders

Self-Cal.

Y coord. Range 3-2 (m)

Require Positioning Accuracy < 1 ns (1 ns = 22cm in seawater).

Triangulation allows 5 cm accuracy


Antares a deep sea 0 1 km neutrino telescope

Buoy

LCM+acoustics Rx2

LCM

LCM

LED beacon

MLCM

LCM+acoustics Rx1

SCM/SPM,

acoustics Rx/Tx

BSS

(6) The Sector Line: Deployment for late ‘02

Optical

Module

Local Control

Module

Optical module

frame

Junction Box

InterLink cable

to shore station


Antares a deep sea 0 1 km neutrino telescope

(7) The Mini Instrumentation Line

Mechanical

Cable

  • Current profiler

    • ADCP 300 kHz of RDI

    • Orientated downwards

    • Current profile for ~150 m depth

    • Resolution: ~ 0.5 cm/s

    • RS232 interface

  • Temperature/Salinity:

    • Model 37-SI MicroCAT

    • Resolution : 10-4 °C, 10-4 S/m

    • RS232 interface

  • Transmissionmeter

    • CSTAR of Wetlabs

    • Measures over 25cm

      • large azimuthal range for labs, lscatt

Sound

Velocimeter

ADCP

Current Profiler

Electro Mechanical Cable

3 fibres for DAQ

100m

Acoustic Positioning

Modules (receivers)

Optical Beacon

CTD

CSTAR

Electro Mechanical Cable

2 fibres for DAQ, 1 for clock

100m

LASER Beacon

Acoustic

Positioning

Modules

2 fibres for DAQ

1 for clock

JB


Antares timeline

ANTARES Timeline

“Demonstrator” line deployment and operation

Collaboration formed

Site evaluation programme to select a suitable site

1996 1997 1998 1999 2000

_________________

2001 2002 2003 2004 2005

Deployment of lines 1 to 10

Sector Line deployment

Sector Line mechanical test

0.1km2 detector

to complete

EO Cable deployed and tested

Technical design report completed


8 conclusion

(8) Conclusion

ANTARES has made excellent progress over the past 4 years :

  • Site environmental characterisationOK

  • Tests of marine technologiesunder control

  • Deployment and operation of Demonstrator String

  • Down-going muons reconstructed in demonstrator

  • Expanding Collaboration

  • ANTARES has entered Phase II of its programme:

  • the design, the installation and commissioning of a 10-string 0.1 km² detector in 2002-2004

  • main electro-optical sea cable successfully deployed

  • - sector line deployment Sept 2002

  • Major step forwardtowardsa km-scale neutrino telescope in the Mediterranean


Antares a deep sea 0 1 km neutrino telescope

THE END

(possible extras follow)


Angular resolution

The angular resolution of the detector depends on

reconstruction algorithms

selection programs

timing accuracy (PMT timing error, positional error on OMs, timing calibration error)

Above 10 TeV the neutrino pointing accuracy

is 0.4 degrees or better including scattering effects

Note: at high energy the error is dominated by reconstruction errors, at low energy by the angle between the muon and neutrino

Angular Resolution


2 1 principal components optical module

(2.1) Principal Components: Optical Module

LED pulser

Optical gel

Photomultipler: 10” Hamamatsu R7081-20

Active (C-W) PMT

Base (ISEG)

Glass sphere (Nautilus)

Mu metal magnetic shield


2 2 principal components hamamatsu r7081 20 characteristics

(2.2) Principal Components: Hamamatsu R7081-20 Characteristics

Sensitive area > 500 cm2;

14 stages; 2.108 Gain @ 2500V;

Transit Time:

typ 60ns @ 1750V (–2.5ns/100V)

(Regularly Measured by LED pulser on each tube)

Transit Time Spread:

s  1.3 ns(spec.):V fixed;

Dark Count Rate

(threshold 0.3 pe equ.): < 10kHz;

Pulse Shape:

Rise Time < 5 ns, FWHM < 12 ns

Quantum Efficiency

Latt(Sphere)

(LoBoro): cm

Latt(Gel): cm

T > 88%


Antares a deep sea 0 1 km neutrino telescope

7 Mb/s

OM

OM

OM

DWDM

DWDM

125 Mb/s

Ethernet Switch

75 kb/s

75 Mb/s

DataWriter

CPU

(2.4) Data Flow Architecture

“Local Control

Module”

LCM

25 Mb/s

LCM

  • OFFSHORE

  • Communication between offshore LCM processors (MPC8xx)

  • and onshore farm (~100 PCs) using Ethernet protocol via

  • optical fibres

  • All data to shore- if bandwidth saturated, an OFFSHORE

  • TRIGGER can be activated to reduce dataflow to just local

  • coincidences

  • Bandwidth of data transmission maximised using DWDM

  • Dense Wavelength Division Multiplexing

  • - Each sector of a string assigned a colour (7 colours/string)

  • - At SCM all colours multiplexed to one pair of fibres

LCM

“Master (sector)

Local Control

Module”

MLCM

LCM

125 Mb/s

“String Control

Module”

SCM

750 Mb/s

from other lines

JB

7.5 Gb/s

  • ONSHORE

  • The colours of each line are

  • demultiplexed

  • All data of current time frame (10ms)

  • assigned to single CPU

  • Each PCs run the DataFilter program

  • which accepts events with time correlated

  • hits

7.5 Mb/s


Energy resolution

Energy Resolution

Different techniques are used in different energy regimes

Below 100 GeV the energy can be estimated from the range of the muon:sE ~ 3 GeV

Use of the hadronic shower energy may improve energy resolution at medium and low E

At energies above 1 TeV the muon energy loss is dominated by catastrophic energy loss (bremss., pair production) which increases with energy. A truncated mean parametrization is used

The corresponding energy resolution is typically a factor of 3 to 4 for E > 1 TeV


5 2 optical beacons for timing calibration precision 0 5 ns cf arrival time precision of om 1 ns

LED (Blue) Beacon (4 per line )

(illuminates several stories of neighboring lines):

MiniPMT for time reference LED pulsers

5.106  8.107g per pulse @ 470nm,

Trise 1.82 ns; FWHM 4.56.5 ns

Green Laser Beacon (Instrumentation line anchor)

(illuminates lower stories of most lines):

Fast pin diode for time reference

Nanolase NG-10120-120 laser head + Diffuser

532 nm; 1 mJ/pulse, Trise 1.82 ns; FWHM 0.8 ns

(5.2) Optical Beacons fortiming calibration precision 0.5 ns:cf arrival time precision of OM ~ 1 ns


3 the antares site1

  • 3.5 sr of sky covered

  • 0.5 sr overlap with Amanda

  • Galactic Centre surveyed

  • Need neutrino telescopesin both hemispheres

(3) The ANTARES Site

Antares Site:

40Km SE Toulon

(42º50’N, 6º10’E)

Depth 2400m

Shore Base

La Seyne-sur-Mer

40 km

Submarine cable

-2400m


3 4 water optical properties transparency1

Variable distance between

LED and PMT “ascenseur”

(3.4) Water optical properties: Transparency

Need in-situ on line monitoring (instrumentation line)


Water transparency

labs~ 55-65 m ;lscat > 100 mat large angles

Water Transparency


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