R. van Dantzig On behalf of the ANTARES Collaboration PHYSICS POTENTIAL, PROGRESS, STATUS ANTARES aims Physics case R & D studies The 0.1 km 2 detector Expected performance Summary

Aims Master deep-sea technologies pressure/corrosion resistant equipment string deployment/recovery power and data connections Measure environmental parameters water (currents, transparency, scattering) optical background ( 40 K, bioluminescence) sensitivity loss (sedimentation, bio-fouling) Design, build, operate ~0.1 km 2 deep-sea -detector with attractive scientific programme prelude to Mediterranean km 3 scale detector R. 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) R. van Dantzig, NOW2000, Otranto

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,...) R. van Dantzig, NOW2000, Otranto 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 rate length: track fit depth: shield atmospheric  background area/volume: adequate event rate length: track fit depth: shield atmospheric  background   e  (pointlike ‘bang’, contained)   decay  ‘double bang’) Earth: filter: upward going -->  R. van Dantzig, NOW2000, Otranto

Detecting (muon) Neutrinos Incoming muon- neutrino traverses the Earth (filter), then interacts and produces muon Muon emits Cherenkov radiation (photons) at ~43 o in seawater Photo-multiplier tube (PMT) in pressure-resistant glass sphere detects photon (arrival time/amplitude ) Sky of the antipodes R. van Dantzig, NOW2000, Otranto

History 1996 Start of the ANTARES Collaboration (in France) 1996–1999 Site exploration (> 30 deployments) Optical water properties Biofouling and sedimentation Optical backgrounds ( 40 K  C and bioluminiscence) 1998–1999 Special tests Mechanics and deployment techniques Submarine connection Apr 1999 Proposal & CDR of a 0.1 km 2 detector Nov 1999 Demonstrator string Large-size demonstrator string deployment and operation 2000 Detailing design, preparations TDR v R. van Dantzig, NOW2000, Otranto

ANTARES site 90 % of the sky covered 17 % overlap with Amanda Galactic Center surveyed  R. van Dantzig, NOW2000, Otranto 40 km SE of Toulon 300 x 300 m m below sea level explored with submarine

Optical Water Properties Absorption length ~ 60m, scattering length > 100m (for large angle scattering) Optical background 40 K ~ 65 kHz (10” PMT) bioluminescence: > 200kHz few seconds bursts overall DT < 5% Sedimentation negligible Biofouling < 2%/year for PMT window R. van Dantzig, NOW2000, Otranto

Conceptual design2400m ~300m active active Electro-optic submarine cable ~40km ~40km Junction box Readout cables Shore station anchor float Electronics containers ~60m Compass, tilt meter hydrophone Optical module Acoustic beacon ~100m 13 strings, 1000 PMTs 12 m between storeys R. van Dantzig, NOW2000, Otranto

Detector design (1) R. van Dantzig, NOW2000, Otranto

Detector design (2) R. van Dantzig, NOW2000, Otranto 10” PMT in 17” 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) trigger Star topology network Gigabit Ethernet 1Fiber per string to shore On-shore Software triggering Linux farm (~100 PCs) 10 ms slice, 1 s processing Reliable, flexible, smart trigger Filtering: event rate < 5 kHz Atmospheric muons < 10 Hz Foreseen: External GRB/SN trigger: all data can be saved for few minutes including last 10 sec before trigger R. van Dantzig, NOW2000, Otranto

Event reconstruction

Expected resolution < ~10 TeV dominated by -  angle. > ~10 TeV < ° (reconstruction error).  E /E  3 (1 TeV  E  10 TeV)  E /E  2 (E  10 TeV) Below E ~ 100 GeV muon range measurement. Angular resolutionEnergy resolution R. van Dantzig, NOW2000, Otranto

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 R. van Dantzig, NOW2000, Otranto boat Mooring line Real time sonar display precision 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 2m2m Top view Top Bottom Tilt x (°)  100 sec Top tiltmeter R. van Dantzig, NOW2000, Otranto

Accoustic positioning Devices Accuracy (  ) Inter-rangemeter< 6 mm Inter-transponder~ 1 cm Range-Transponder  6 cm 4 transponders 3 rangemeters +Sound velocitymeter 2cm Triangulation allows ~5 cm accuracy R. van Dantzig, NOW2000, Otranto

Demonstrator events More than 5  fold coincidence events recorded (atmospheric muons) Polar angle deduced from depth (z) vs. time pattern with hyperbolic fit (including multimuons). 40 K 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

Summary ANTARES has succesfully performed the planned R&D programme Site exploration (environmental parameters) Conceptual design of a 0.1 km 2 detector Detailed tests of components Verification of undersea connection procedure Design, deployment, operation of a demonstrator string Current planning: ~ 0.1 km 2 detector to be deployed gradually between 2002 and 2004 Such a detector can be a thorough test-bench for a 1 km 3 neutrino telescope in the Mediterranean Sea and have a viable exploratory physics programme. R. van Dantzig, NOW2000, Otranto

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, NOW2000, Otranto