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KM3NeT - a next generation neutrino telescope in the Mediterranean Sea

KM3NeT - a next generation neutrino telescope in the Mediterranean Sea. For the KM3NeT Collaboration Petros A. Rapidis National Center for Scientific Research “Demokritos”, Athens, Greece and NESTOR Experiment Collaboration.

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KM3NeT - a next generation neutrino telescope in the Mediterranean Sea

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  1. KM3NeT -a next generation neutrino telescope in the Mediterranean Sea For the KM3NeT Collaboration Petros A. Rapidis National Center for Scientific Research “Demokritos”, Athens, Greece and NESTOR Experiment Collaboration Presented at TAUP 2007 - Tenth International Conference on Topics in Astroparticle and Underground Physics ; September 11-15, 2007; Sendai (Japan)

  2. What is KM3NeT ? An acronym for cubic kilometer sized (km3) sea water neutrino telescope. It is a European Consortium funded by EC FP6* whose goal is a Design Study for a: Deep Sea Facility in the Mediterranean for Neutrino Astronomy and Associated Sciences - started February 2006 • Associated Sciences: • Oceanography • Marine Biology • Environmental Sciences • Geology and Geophysics * 6th Framework Program of the European Commission to support the ‘European Research Area’

  3. KM3NeT consortium Comprises of 37 institutes from: Cyprus, France, Germany, Greece, Ireland, Italy, The Netherlands, Spain, and The United Kingdom … other groups are welcomed ! Builds upon the experience of the past ‘pilot’ projects : +.. + + Not to forget DUMAND, BAIKAL, and other (frozen) water based projects.

  4. Design study: 2006-2009 • Technical Design Report • Preparatory phase: 2008-2011 (proposal submitted) • Political convergence (site) • Commitment for construction of funding agencies/ministries • Governance and legal structure • System prototype • Tendering procedures • Construction phase: 2010-2013 • Build 1 km3 detector

  5. Draft KM3NeT timeline Design Study Preparatory Phase Construction Jan 2008 Mid 2010 Feb 2006 Assembly model Tenders CDR TDR Now Financial plan Production model for detection unit Targeted budget: 220-250 M€ (ESFRI roadmap) !!

  6. KM3NeT Design Study objectives • Effective volume  1 km3 • Angular resolution for muons: 0.1o (for neutrino energies 10 TeV) • Energy threshold: few 100 GeV (~100 GeV when pointing) • Sensitivity to all neutrino flavours, CC/NC reactions • Field of view: close to 4 for high energies

  7. Outline of the rest of the talk : • Why ? (what is the physics case) • The way towards a km3 detector • The KM3NeT Design Study • Where are we now? Cosmic Neutrino Sources Pulsar Wind Nebula Supernova Remnants Microquasars Galactic: RX J1713.73946HESS Gamma Ray Bursts Extra - Galactic: (GRB970228, BeppoSax) Active Galactic Nuclei We live in a truly active universe ! (as HESS has emphasized!)

  8. Directional aspects of neutrino telescopes Muon neutrinos for identification of individual sources (need good angular resolution) Muons can penetrate several km of water if E ν> 1 TeV ⇒ huge background from atmospheric ν, hence the need for a deep underwater site Sensitivity for sources “above” much reduced needs either very high energies or short transients (e.g., GRBs)

  9. Neutrino astronomy Mkn 421 Mkn 501 CRAB CRAB VELA SS433 SS433 Mkn 501 RX J1713.7-39 GX339-4 Galactic Centre Antartica Mediterranean Sea

  10. → We need Northern νtelescopes to cover the Galactic Plane

  11. ν Flux Predictions from γRay Measurements Example: Vela X (PWN) Measured γ ray Flux (H.E.S.S.) mean atm. flux (Volkova, 1980, Sov.J. Nucl.Phys., 31(6), 784 expected neutrino flux – Sensitivity for KM3NeT A. Kappes et al., ApJ 656:870, 2007 (astroph/0607286) Such calculations show that we need km3scale detectors

  12. The ‘pilot’ projects ANTARES, NEMO, NESTOR • Presentations earlier in this session – • V. Bertrand, Status report on the ANTARES Neutrino Telescope • P. Sapienza, NEMO • Thus no need to elaborate more about them here. Site features : Multiple depths at relatively close distances from the shore. The deepest point in the Mediterranean

  13. A different approach from Antares – based on towers than strings – so as to minimize undersea connections One floor (star) deployed in 2003 at 4000m and measured muon flux. (reported in previous TAUP) Plan to deploy 4 or 5 floors this summer – and in conjunction with four autonomous strings carry out the NuBE proposal (neutrino burst experiment) with the aim of observing neutrino – gamma ray burst coincidences (>2km2 effective area) 300 m

  14. ~4,000m from the surface  ~400m Exploring the path of extrapolating the present experience towards the design of a much larger structure Existing telescopes “times 30” ? • Too expensive • Too complicated (production, maintenance) • Not scalable (readout bandwidth, power, ...) Repeat as needed ? No ! New design ? R&D needed: • Cost effective solutions reduce price/volume by factor of at least 2 • Stability goal: maintenance free detector • Fast installation time for construction & deployment less than detector life time • Improved components Expand it ? No ! Large volume with same number of PMs? • PM distance: given by absorption length in water (~60 m) and PM properties • Efficiency loss for larger spacing

  15. Smart tube X-HPD (R&D) Segmentation of photo cathode of 10” PMT multi PMTs in one glass sphere Ref. ICRC0489, P. Kooijman New technologies are being investigated New designs for optical modules “Flykt” sphere

  16. New designs for data transmission – communications - controls • Extension of present systems (e.g. ANTARES readout) • Wire – fiber network 1:1 system • Fully photonic system • Considerations of local (in the sea) vs. remote (on shore) data acquisition. • Towers vs. strings ? Or both ? • How much should we fear and avoid a wet mateable connection ? Is an ROV the best option ? What are the risks ? • Use general purpose telecom cable ships vs. dedicated vessels ? New designs for structures – deployment issues Catania meeting taking place now Delta Vereniki final major contract was awarded 10 days ago – expected functional in 5-6 months

  17. SeaTop? ...for calibration only ? Three stations at 20 m distances with 16 m2 scintillators each • Calibration: • angular offset • efficiency • angular resolution • absolute position

  18. Simulating various configurations Cubic, Ring, Hexagonal, Clustered, IceCube-like ... Usually with Antares environmental parameters

  19. Estimating the neutrino effective area Configuration 1 (1 km3): 127 lines in hexagonal array 100m line spacing 25 stories, 15 m apart 3 Antares (10”) PMTs per story Configuration 2 (1 km3): 225 lines in a cubic grid 95m line spacing 36 stories, 16.5 m apart 21x3”PMTs per story Antares site parameters Ref. ICRC0865, J. Carr et al Thesis S. Kuch, Erlangen

  20. Ref. ICRC0865, J. Carr et al Estimated sensitivity to HESS sources Neutrino energies 1TeV – 1 PeV Muon event rates for 5 years of data taking

  21. Estimated diffuse flux limit Configuration 2: 225 strings with lower half sphere multiPMTs No atmospheric muon background taken into account No energy reconstruction applied Thesis S. Kuch, Erlangen

  22. Thesis S. Kuch, Erlangen Estimated E-2 flux limit Configuration 2: 225 lines with lower half sphere mulitPMTs 21 x 3” PMTs No atmospheric muon background taken into account Perfect muon energy reconstruction Neutrino energies 1 TeV – 1 PeV

  23. Site selection • KM3NeT report input for discussion: Evaluation of existing water, oceanographic, biological and geological data from candidate sites Final choice will depend on • Depth • Distance from shore • Bioluminescence rate • Sedimentation • Biofouling • Sea currents • Earth quake profile • Access to on-shore high speed networks • …… • Socio-political/regional considerations ?

  24. KM3NeT phases • Design study: 2006-2009 • Technical Design Report • Preparatory phase: 2008-2011 (proposal submitted) • Political convergence (site) • Commitment for construction of funding agencies/ministries • Governance and legal structure • System prototype • Tendering procedures • Construction phase: 2010-2013 • Build 1 km3 detector

  25. The KM3NeT Vision • KM3NeT will be a multidisciplinary research infrastructure: • Data will be publicly available; • Data will be buffered to respond to GRB alerts etc. • Deep sea access for marine sciences. • KM3NeT will be a European project • 8 European countries involved in the Design Study; • Substantial funding already now from national agencies. • E.g. the Greek government has committed to 50 M€. • KM3NeT will be constructed in time to take data concurrently with IceCube. • KM3NeT will be extendable. • ------------------------------------ • KM3NeT is breaking new ground in the creation/management of multinational projects in the EU – ESFRI framework.

  26. Backups …

  27. ν 's from Galactic Sources Example: SNR RX J1713.73946 (shell type supernova remnant) H.E.S.S. : E = 200 GeV – 40 TeV Acceleration beyond 100 TeV. Power law energy spectrum, index ~2.1–2.2. Spectrum points to hadron acceleration ν flux ~ γ flux Typical ν energies: few TeV

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