r. van dantzig on behalf of the antares collaboration physics potential, progress, status antares...

R. van Dantzig

On behalf of the ANTARES Collaboration

PHYSICS POTENTIAL, PROGRESS,

STATUS

• ANTARES aims• Physics case• R&D studies• The 0.1 km2 detector• Expected performance• Summary

AimsMaster deep-sea technologies• pressure/corrosion resistant equipment• string deployment/recovery• power and data connections

Measure environmental parameters• water (currents, transparency, scattering)• optical background (40K, bioluminescence)• sensitivity loss (sedimentation, bio-fouling)

Design, build, operate ~0.1 km2 deep-sea -detector with attractive scientific programmeprelude to Mediterranean km3 scale

detectorR. van Dantzig, NOW2000, Otranto

Th Physics case (1)

GZK

UHE

R. van Dantzig, NOW2000, Otranto

Cosmic Ray spectrum

beam(p)+dump(p,)

How does the spectrum look like?

Physics case (2)MESSENGERS FROM THE SKY

• Photons !! (but limitations GZK 50 Mpc E>TeV) interaction with matter/radiation/CMB ( --> e+e-)

• protons, nuclei (GZK 50 Mps E > ~50 EeV) interaction with matter/radiation/CMB magnetic deflection (E < ~EeV)

• neutrons (boosted decay length 10 kpc E<~ EeV)

• neutrinos (of all energies)• can cross cosmological distances (weak interactions only)• can point back to their source (no charge, no magnetic deflection)


Physics case (3)ASTROPHYSICS & ASTRONOMY point sources (powerful (extra)-galactic objects)

same sky coordinates of several events (AGN, SNR, ..) coincidence in time (GRB)

diffuse flux energy spectrum, sky distribution,flavour composition

COSMOLOGY & DM local sources (Earth, Moon, Sun, galactic center)

indirect search for gravitationally trapped WIMPS (neutralinos)

and topological defects: GUT phase transition remnants

PARTICLE PHYSICS

oscillations (atmo / astro exotics (Dirac monopoles, strangelets, ...)


Other talk in this workshop

But, detecting s ... • track)

CC exchange with matter near detector

N cross section increases with E

• HE’s statistically enhanced angle small ( direction ~ -

direction) N spectrum ~ E-2

area/volume: adequate event ratelength: track fitdepth: shield atmospheric

background

area/volume: adequate event ratelength: track fitdepth: shield atmospheric

background

e(pointlike ‘bang’, contained) decay‘double bang’)

Earth: filter: upward going -->


Detecting (muon) Neutrinos

Incoming muon-neutrino traverses the Earth (filter), then interacts and produces muon

Incoming muon-neutrino traverses the Earth (filter), then interacts and produces muon

Muon emits Cherenkov radiation (photons) at ~43o in seawater

Muon emits Cherenkov radiation (photons) at ~43o in seawater

Photo-multiplier tube (PMT) in pressure-resistant glass sphere detects photon (arrival time/amplitude)

Photo-multiplier tube (PMT) in pressure-resistant glass sphere detects photon (arrival time/amplitude)

Sky of the antipodesSky of the antipodes


History 1996 Start of the ANTARES Collaboration (in

France)

1996–1999 Site exploration (> 30 deployments)

Optical water properties

Biofouling and sedimentation

Optical backgrounds (40K C and bioluminiscence)

1998–1999 Special tests

Mechanics and deployment techniques

Submarine connection

Apr 1999 Proposal & CDR of a 0.1 km2 detector

Nov 1999 Demonstrator string

Large-size demonstrator string deployment and operation

2000 Detailing design, preparations TDR

v



ANTARES site

90 % of the sky covered

17 % overlap with Amanda

Galactic Center surveyed


40 km SE of Toulon

300 x 300 m2

2400 m below sea level

explored with submarine

Optical Water Properties

Absorption length ~ 60m, scattering length > 100m (for large angle scattering)

Optical background40K ~ 65 kHz (10” PMT) bioluminescence: > 200kHz few seconds burstsoverall DT < 5%

Sedimentation negligible

Biofouling < 2%/year for PMT window


Conceptual design

2400m2400m

~300m~300m activeactive

Electro-opticElectro-opticsubmarine cablesubmarine cable ~40km~40km

Junction boxJunction box

Readout cablesReadout cables

Shore stationShore station

anchoranchor

floatfloat

Electronics containersElectronics containers

~60m~60mCompass,Compass,tilt metertilt meter

hydrophonehydrophone

Optical moduleOptical module

Acoustic beaconAcoustic beacon

~100m

13 strings, 1000 PMTs12 m between storeys


Detector design (1)


Detector design (2)


10” PMT in17” glass sphere

Electronics in container

ASIC chip (ARS)front-end digitization

DAQ: transmission and selection

Offshore

Full digitization (ASIC chip)Low threshold (~0.3 pe) No (or minimum bias) triggerStar topology networkGigabit Ethernet1Fiber per string to shore

On-shore

Software triggeringLinux farm (~100 PCs)10 ms slice, 1 s processingReliable, flexible, smart triggerFiltering: event rate < 5 kHzAtmospheric muons < 10 Hz

Foreseen:External GRB/SN trigger: all data can be saved for few minutes including last 10 sec before trigger


Event reconstruction

Expected resolution

< ~10 TeV

dominated by - angle.

> ~10 TeV < 0.2 - 0.4° (reconstruction error).

E /E 3 (1 TeV E 10 TeV)

E /E 2 (E 10 TeV)

Below E ~ 100 GeV muon range measurement.

Angular resolution Energy resolution


Demonstrator string

• Full-scale line (340 m) test of mechanics and deployment

• Partially instrumented: 7 PMTs, CTDs, tiltmeters, positioning system, Slow Controls, etc.

• Read-out via electro-optical cable.

• Operational for several months starting December 1999


boat

Mooring line

Real time sonar displayprecision positioning

Compass and tiltmeters

• Taut string at ~2.3º from vertical.

• Tilt stability: ~0.2º over one week (x and y).

• Heading stability: 2º over one week.

Very stable Negligible twist

2 m

Top view

Top

Bottom

Tilt x (°)

100 sec

Top tiltmeter


Accoustic positioning

Devices Accuracy ()

Inter-rangemeter < 6 mm

Inter-transponder ~ 1 cm

Range-Transponder

6 cm

4 transponders 3 rangemeters+Sound velocitymeter

Triangulation allows ~5 cm accuracyR. van Dantzig, NOW2000, Otranto

Demonstrator events

• More than 5104 7-fold coincidence events recorded (atmospheric muons)

• Polar angle deduced from depth (z) vs. time pattern with hyperbolic fit (including multimuons).

• 40K filtered out by reconstruction software (see box hit).

z (m

)

ct (m)

z (m

)

ct (m)R. van Dantzig, NOW2000, Otranto

Demonstrator results

Angular distribution agrees with expectations from single + multi-muons

Fit residuals ~ 6 ns

~1100/day reconstructable downgoing ’s (in agreement with MC expectation)R. van Dantzig, NOW2000, Otranto

SummaryANTARES has succesfully performed the planned R&D programme

Site exploration (environmental parameters)

Conceptual design of a 0.1 km2 detector

Detailed tests of components

Verification of undersea connection procedure

Design, deployment, operation of a demonstrator string

Current planning: ~ 0.1 km2 detector to be deployed gradually between 2002 and 2004

Such a detector can be a thorough test-bench for a 1 km3 neutrino telescope in the Mediterranean Sea and have a viable exploratory physics programme.


• France• CPPM Marseille

(IN2P3)• DAPNIA-DSM Saclay

(CEA)• IReS, Strasbourg-

Mulhouse• Centre d’Oceanologie

de Marseille• Institut Francais de

Recherche pour l’Exploitation de la Mer (IFREMER)

• INSU-CNRS/IGRAP (Provence)

• Spain• IFIC Valencia

• Russia• ITEP Moscow

• United Kingdom• University of Birmingham• University of Oxford• University of Sheffield

• Netherlands• NIKHEF Amsterdam

• Italy• University of Bari (INFN)• University of Bologna (INFN)• University of Catania (INFN)• LNS (INFN)• University of Rome (INFN)• University of Genova (INFN)

•The ANTARES Collaboration


r. van dantzig on behalf of the antares collaboration physics potential, progress, status antares...

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