ANTARES Lessons learned from its completion Thomas Eberl on behalf of the ANTARES Collaboration Erlangen Centre for Astroparticle Physics Erlangen University NNN08 Workshop, Paris, Sept. 12th, 2008

The ANTARES Collaboration 23 institutes in 7 European countries

The ANTARES Collaboration 23 institutes in 7 European countries

Geographical location of ANTARES 40 km submarine cable Depth: 2475 m Toulon

Goal: Discover high energy cosmic neutrinos! gammas (0.01 - 1 Mpc) protons E>1019 eV (100 Mpc) protons E<1019 eV Cosmic accelerator neutrinos 1 parsec (pc) = 3.26 light years (ly) Photons: absorbed on dust and radiation Protons/nuclei: deflected by magnetic fields, reactions with radiation (CMB)

Sources of cosmic neutrinos Photons and gas around sources, e.g. SN remnants, accretion discs around BHs, GRBs p + g p + po  p + g + g n + p+  n + nm + m e+ + nm + ne p + p  N + N + p  g , n … 2) Molecular clouds p + p  N + N + p  g , n .... 3) CMB photons p + g  D  N + p  g , n ...

ANTARES Detector 350 m storey 14.5 m cable to shore 100 m Junction Box 45° 350 m 12 lines 25 storeys / line 3 PMTs / storey 900 PMTs Calibration systems: Acoustic positioning Optical beacons 14.5 m cable to shore 2500m depth 100 m Junction Box ~70 m Anchor/line socket Link cable M. Spurio- ANTARES 7

Main detection principle of a neutrino telescope p, a 107  atm m gč 43° Sea floor Cherenkov light from m p a  g n reconstruction of m – track (~ n) from time & pos. of fired PMTs aCh ~ 42º Cherenkov light from m m

Status: Detector complete since May 30, 2008 IL07 seismo 100 m N Junction box Submarine cable to shore 42°50’ N 6°10’E 12 lines with 900 PMTs and 1 instrumentation line IL07 for the control of environmental parameters (e.g. sea current, temperature, ...)

Duration of lines in sea up to 2.5 y Junction Box operational in deep sea since 5.5 years Line 1 works for more than 2 years

Cable Failure and Repair Standard 40 km deep-sea telecommunications cable used to connect shore station and junction box. Cable failed in July 08, connection to detector was lost. Investigations showed that sea water had penetrated 100m into the cable. Successful and standard repairing procedure by France Telecom Ship 8 days ago! ANTARES is back online status of detector is unchanged.

Reliability of detector ONLINE CONTROL ~ 12% of channels w/ low or w/o count rate mostly power or HV failure 2 sectors (= 5 floors, red) are unreachable Floor nb Technology is proven to work but: some imperfections which are being investigated Line nb 12

Optical background rates Dominated by 2 effects 1. b – decay of 40K 2. bioluminescent organisms e.g. 40K 40Ca e- γ

Light pollution in the deep sea changes with time! Background Light Rate Median counting rate in 10” PMT in Line 1 Base line at 50 to 80 kHz March 2006 – May 2008 Light pollution in the deep sea changes with time! Now: 90% of time mean rate <= 60 kHz  o.k. for event reconstruction

Calibration with Potassium-40 tuning 2 tuning 1 40K coincidence rate during 18 months Under investigation: PMT ageing? Gain drop compensated by threshold tuning on average ~35 photons 40K decay (β or EC)

Acoustic triangulation Compass data of storeys: headings and tilts Acoustic positioning 25 20 14 8 1 Anchor with transponder Determination of line shape and of module coordinates once per minute by Acoustic triangulation Compass data of storeys: headings and tilts

Alignment with acoustic positioning Hydrophone positions relative to line anchor Data from July  Dec 2007 Storey 1 Storey 8 Storey 14 Storey 20 Storey 25 Crucial to reach track resolution < 1 degree Lines are floating with the deep sea water current ! Typical water speed: a few cm/s Necessary precision is reached  positioning is under control

Reconstructed events with 10 lines Data: Dec 2007 – Apr 2008 : 100 active days preliminary from below from above 208 neutrinos

Summary ANTARES is complete and the first operational deep-sea neutrino telescope Technology is proven, some imperfections which are under control Detector and Calibration is being understood Data analysis: - more than 400 clean neutrino events selected - comparison to MC and syst. error estimation in progress Ready for next step with KM3NeT Detector …

What is KM3NeT ? Future cubic-kilometre scale neutrino telescope in the Mediterranean Sea based on expertise of all pilot projects: ANTARES, NEMO and NESTOR EU-funded design study (9M €, 2006-2009) ESFRI roadmap project Preparatory Phase (2008-2011) started Exceeds Northern-hemisphere telescopes by factor ~50 in sensitivity Exceeds IceCube sensitivity by substantial factor Focus of scientific interest: Neutrino astronomy in the energy range 1 to 100 TeV

KM3NeT: Timeline towards construction Note: “Construction” includes the final prototyping stage

The KM3NeT Conceptual Design Report Presented to public at VLVnT08 workshop in Toulon, April 2008 Summarises (a.o.) Physics case Generic requirements Pilot projects Site studies Technical implementation Development plan Project implementation available on www.km3net.org