1. 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

2. The ANTARES Collaboration
23 institutes in 7 European countries

3. The ANTARES Collaboration
23 institutes in 7 European countries

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

5. Goal: Discover high energy cosmic neutrinos!
gammas ( 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)

6. 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 ...

7. 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

8. 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

9. 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, ...)

10. 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

11. 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.

12. 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

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

14. 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

15. 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)

16. 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

17. 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

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

19. 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 …

21. 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 €, )
ESFRI roadmap project Preparatory Phase ( ) 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

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

23. 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