KM3NeT, a deep sea neutrino telescope in the Mediterranean Sea

1. KM3NeT, a deep sea neutrino telescope in the Mediterranean Sea Anastasios Belias for the KM3NeT Consortium KM3NeT objectives The KM3NeT Design Study Outlook TeVPA 2009, July 13-17, SLAC

2. We need Northern n-telescope to cover the Galactic Plane Complementarity with Ice Cube coverage A n-telescope in the Mediterranean sea TeVPA 2009, July 13-17, SLAC

3. The KM3NeT Consortium • Consists of 40 Institutes of 10 European States • Includes expertise from all three precursor projects, ANTARES, NEMO, NESTOR • Objectives • Build and operate an extensible km3-scale water Cherenkov neutrino telescope in the Mediterranean Sea • Sustain a deep-sea research infrastructure for earth and marine sciences • KM3NeT, a multidisciplinary research infrastructure • Synergetic with European Multidisciplinary Seafloor Observatory (EMSO) TeVPA 2009, July 13-17, SLAC

4. KM3NeT Objectives • Astroparticle physics with neutrinos • “Point sources”: Galactic and extragalactic sources of high-energy neutrinos • The diffuse neutrino flux • Neutrinos from Dark Matter annihilation • Search for exotics • Magnetic monopoles • Nuclearites, strangelets, … • Neutrino cross sections at high(est) energies • The unexpected • Earth and marine sciences • Long-term, continuous measurements in deep-sea • Marine biology, oceanography, geology/geophysics, … TeVPA 2009, July 13-17, SLAC

5. The KM3NeT Design Study • Supported by the European Union in FP6 with ~9M€, tot. value ~20M€. • Timeline: • Started on Feb. 1, 2006 and will end on Oct. 31, 2009 • Conceptual Design Reportpublished, April 2008 • Technical Design Reportby end of 2009 • Detector Target Specifications: • Effective volume ≥ 1km3 • 0.1o angular resolution for muons (E ≥ 10TeV) • Energy threshold few 100 GeV • Field of view close to 4π for high energies TeVPA 2009, July 13-17, SLAC

6. Deep-sea n-Telescope at work Upward-going neutrinos interact in rock or sea water. Emerging charged particles (in particular muons) produce Cherenkov light in water. Detection by array of photomultipliers. Focus of scientific interest: Neutrino astronomy in the energy range 1 to 100 TeV. TeVPA 2009, July 13-17, SLAC

7. Optical Module: standard... • A standard optical module, as used in ANTARES, NEMO, NESTOR • Typically a single large diameter (10’’) PMT in a 17’’ glass sphere TeVPA 2009, July 13-17, SLAC

8. … or many small PMTs • Use up to 31 small (3’’) PMTs in a standard 17’’ glass sphere • very high QE PMTs • Advantages: • increased photocathode area • significant improved TTS • directionality • improved 1-vs-2 photo- electron separation  better sensitivity to coincidences • Prototype tests underway TeVPA 2009, July 13-17, SLAC

9. Electronics & Data Readout Concepts • Front-end options studies • New improved front-end chip in the deep-sea • New FPGA/CPU • Minimize active electronics in deep-sea • Reflective optical modulator • on-shore timestamp • Both options use fibers, Wavelength Division Multiplexing and Point-to-point networks • “ALL DATA TO SHORE” Submarine Telecom cable Interlink cables TeVPA 2009, July 13-17, SLAC

10. Shore station real-time processing • ALL digitized PMT data are sent to shore • Expected rate of ~ 100Gb/s cannot be stored • Perform time - position correlations of photomultiplier hits • Correlations in real-time for the whole telescope • Data reduction factor: ~10000 TeVPA 2009, July 13-17, SLAC

11. Configuration studies • Various geometries and OM configurations have been studied • None is optimal for all energies and directions • Local coincidence requirement poses important constraints on OM pattern TeVPA 2009, July 13-17, SLAC

12. Mechanical structures • Flexible tower structure: Tower deployed in compactified “package” and unfurls thereafter • String structure: Compactified string at deployment, unfolding on sea bed TeVPA 2009, July 13-17, SLAC

13. Deployment & Sea Operations All deployment options require ships or platforms with GPS and DP • Deployment with ships or dedicated platforms. • Ships: Buy, charter or use ships of opportunity. • Platform: Delta-Berenike, under construction in Greece • Deep-sea submersibles • Remotely operated vehicles (ROVs) • Autonomous Undersea Vehicles (AUVs) under study Delta-Berenike: triangular platform, central well with crane, water jet propulsion TeVPA 2009, July 13-17, SLAC

14. Earth and Marine Sciences • Associated sciencedevices will be installed at variousdistances aroundneutrino telescope • Issues addressed: • operation withoutmutual interference • interfaces • stability of operationand data sharing TeVPA 2009, July 13-17, SLAC

15. The candidate sites • Important Criteria • Bioluminescence rate • Biofouling • Sedimentation • Sea Currents • Absorption length • Depth • Distance from Shore • Access to shore facilities • Long-term site measurementsperformed and ongoing • Site decision requiresscientific, technologicaland political input TeVPA 2009, July 13-17, SLAC

16. Site characterisation: Example NESTOR 4.5 D Site 36O 31.336’ N / 21O 25.635’ E Transmission length vs wavelength TeVPA 2009, July 13-17, SLAC

17. KM3NeT Roadmap • Design study Feb. 1, 2006 – Oct. 31, 2009 • Produced Conceptual Design Report • Will produce Technical Design Report (by end. 2009) • “Preparatory Phase” EU funded ~5M€, tot. ~10M€ 3/2008 – 2/2011 • Initiate political process towards convergence and legal structure • Prepare operation organisation & user communities • System prototypes • Commitment of funding agencies • Site selection around 2010 ? • Construction Phase 2011+ • Start on extendable km3–scale neutrino telescope TeVPA 2009, July 13-17, SLAC

18. KM3NeT Technical Design Report will address key issues • Maximize physics output for given budget: • Which architecture and structure to use? • String vs Tower concept • How to get the data to shore? • Electronics off-shore or on-shore • How to calibrate the detector? • Separate calibration and detection units • Design of photo-detection units? • Large vs several small PMTs • Deployment technology? • Dry vs wet ROV/AUV vs hybrid TeVPA 2009, July 13-17, SLAC

19. Outlook • Joint efforts of ANTARES, NEMO, NESTOR to build a km3-scale neutrino telescope in the Mediterranean Sea • The Technical Design Report will be ready by end 2009 • The Preparatory Phase started • Towards construction to start in 2011+ • Thekm3-scale neutrino telescopein the Mediterranean Sea will complement IceCube in its field of view TeVPA 2009, July 13-17, SLAC

20. TeVPA 2009, July 13-17, SLAC

21. Backup slides TeVPA 2009, July 13-17, SLAC

22. Simulations of reference detector • Sensitivity studies with a common detector layout • Geometry: • 15 x 15 vertical detection units on rectangular grid,horizontal distances 95 m • each carries 37 OMs, vertical distances 15.5 m • each OM with21 3’’ PMTs Effective area of reference detector This is NOT the final KM3NeT design! TeVPA 2009, July 13-17, SLAC

23. Point source sensitivity • Based on muon detection • Why factor ~3 more sensitive than IceCube? • larger photo-cathode area • better direction resolution • Study still needs refinements TeVPA 2009, July 13-17, SLAC

24. Diffuse fluxes • Assuming E-2neutrino energy spectrum • Only muonsstudied • Energy reconstruction not yet included TeVPA 2009, July 13-17, SLAC