KM3NeT, INFN SciNeGHE 2010, Trieste, september 8 10 2010
Overview Introduction The KM3NeT Technical Design Report KM3NeT physics performances New developments Summary 2
Motivations for High Energy neutrino astronomy Neutrinos will provide unique pieces of information on the High Energy Universe Physics case Astrophysical high energy neutrino sources (SNR, microquasars, AGN, GRB) Origin of cosmic rays Unknown neutrino sources Indirect search of Dark Matter 3
Detection Principle Upward-going neutrinos interact in rock or ice or sea/lake water. Emerging charged particles (in particular muons) produce Cherenkov light in water/ice Detection by array of photomultipliers Muon direction reconstructed from photon arrival times and PMT positions Estimates indicate that a km3 scale detector is needed for ν astronomy 4
High energy neutrino telescope world map Pylos ANTARES, NEMO, NESTOR Baikal Mediterranean km 3 La Seyne Capo Passero 5 AMANDA IceCube
What is KM3NeT? The KM3NeT consortium consists of 40 European institutes including those in Antares, Nemo and Nestor KM3NeT is one of the 40 Research Infrastructures of the ESFRI roadmap KM3NeT Design Study defined telescope design and outlined main technological options Approved under the 6 FP (funded by EU for the period 2006-2009) Conceptual Design Report published in 2008 (http://www.km3net.org/cdr/cdr-km3net.pdf) Technical Design Report (TDR) outlines technologies for the construction, deployment and maintenance of a deep sea neutrino telescope (http://www.km3net.org/tdr/prelim-tdr-km3net.pdf) (TDR contents frozen in November 2009) KM3NeT Preparatory Phase define legal, governance and funding aspects. Production planes for the detector elements, infrastructure features and prototype validation will be also defined Approved under the 7 FP (funded by EU for the period 2008-2012) 6
KM3NeT main objectives Energy range and main physics goals Investigate neutrino point sources optimisation in the energy regime 1-100 TeV with a coverage of most of the sky including the Galactic Centre Not in the central focus: Dark Matter Neutrino particle physics Exotics (Magnetic Monopoles, Lorentz invariance violation, ) Implementation requirements Construction time 5 years Operation over at least 10 years without t major maintenance Provide a deep-sea cabled platform for Sea and Earth sciences 7
Sky view of a Mediterranean Sea Telescope Sensitivity for up-going neutrinos considered From Mediterranean 24h per day visibility up to about δ= -50 >25% >75% KM3NeT complements the IceCube field of view KM3NeT observes a large part of the sky (~3.5π) 8
Schematic view of KM3NeT Detection Units Primary Junction box Secondary Junction boxes Electro-optical cable 9
Technical Challenges and Telescope Design Technical design Objective: Support 3D-array of photodetectors and connect them to shore (data, power, slow control) Optical Modules Front-end electronics & readout Readout, data acquisition, data transport Mechanical structures, backbone cable General deployment strategy Sea-bed network: cables, junction boxes Calibration devices Shore infrastructure Assembly, transport, logistics Risk analysis and quality control Described in the KM3NeT Technical Design Report http://www.km3net.org/tdr/prelim-tdr-km3net.pdf Design rationale: Cost-effective Reliable Producible Easy to deploy Builds on the experience gained with ANTARES, NEMO and NESTOR 10
Other issues addressed in the Design Study Site characteristics Measure site characteristics (optical background, currents, sedimentation, ) Simulation Determine detector sensitivity Optimise detector parameters Earth and Sea science requirements Define the infrastructure needed to implemement multidisciplinary science nodes 11
TDR Optical Module major alternative options Single-PMT Optical Module 8-inch PMT with 35% quantum efficiency inside a 13 inch glass sphere Evolution from pilot projects Multi-PMT Optical Module 31 small PMTs (3-inch) inside a 17 inch glass sphere 31 PMT bases (total ~140 mw) Cooling shield and stem First full prototype ready at the end of 2010 12
TDR Detection Unit alternative options Flexible tower with horizontal bars equipped with single-pmts or multi-pmt OMs Triangular arrangements of OMs with single-pmts or multi-pmt Evolution of the ANTARES storey Slender string Vertical sequence of multi-pmts OMs Simulations indicate that local 3D OM arrangement resolve ambiguities in the reconstruction of the muon azimuthal angle 13
Deployment strategy Compact package deployment self-unfurling Eases logistics (in particular in case of several assembly lines) Speeds up and eases deployment; Self-unfurling concepts need to be thoroughly tested and verified Connection to seabed network by Remotely Operated Vehicle (ROV) The packed flexible tower Spherical deployment structure for string with multi-pmt OM Successful deployment test in Feb 2010 Successful deployment test in Dec 2009 14
Readout and data transfer All-data-to-shore data transfer with point-to-point connection from DU storey to shore Front-end electronics: Time Over Threshold with ASIC chip 15
Seafloor architecture Star-like geometry for 127 DU 1 detector building block Requirements Power distribution from shore to DUs Support data network Slow control and communication Structure Hierarchical topology Primary and Secondary Junction Boxes Commercial electro-optical data cables and connectors Intallation with ihrov Layout Depends on DU design, deployment procedure andoptimization of the detector footprint 16
Optimization studies Example: sensitivity dependence of point-source search on DU distance for flexible towers (for 2 different neutrino fluxes ~E - α, no cut-off) α = 2.2 α = 2.0 17
Effective area and angular resolution Effective up-going neutrino area Angular resolution Median of ΔΩ ν μrec median of ΔΩ ν μ Quality Cuts (0.2 @30TeV) Quality cuts from sensitivity optimization μ θ ν μ 18
Sensitivity and discovery potential Sensitivity and discovery fluxes for point like sources with E -2 spectrum for 1 year of observation time binned method unbinned method KM3NeT sensitivity 90%CL KM3NeT discovery 5s 50% IceCube sensitivity 90%CL IceCube discovery 5σ 50% 2.5 3.5 above sensitivity flux. (extrapolation from IceCube 40 string configuration) Observation of RXJ1713 at 5σ within about 5 years Observed Galactic TeV g sources (SNR, unidentified, microquazars) F. Aharonian et al. Rep. Prog. Phys. (2008) Abdo et al., MILAGRO, Astrophys. J. 658 L33 L36 (2007) Galactic Centre Sensitivity and discovery potential will improve with unbinned analysis 19
Some considerations on the design Construction possible with viable technologies Required performances reachable within the foreseen budget of 220 M The design strongly builds on the experience gained with Antares, Nemo and Nestor Staged implementation i possible Science potential from very early stage of construction on 20
Developments after the TDR Contents of the Technical Design Report frozen in november 2009 Since then major effort towards the construction and validation of a Pre-Production Model of the DU Bar option with horizontal extent Optimised design and plan for extensive deployment tests defined Multi-PMT Optical Module Development plan for validation of technology and integration procedures defined Optimization of simulation of the detector performance ongoing Deployment of first prototype DU planned end 2011 21
Packaging of a20 storey Detection Unit m 2.6 m 22
Multi PMT Optical Module 23
Candidate sites Three candidate sites Toulon (France) Capo Passero (Italy) Pylos (Greece) Long-term site characterization measurements performed Site decision requires scientific, technological and political input Multi-site option under study in the Preparatory Phase 24
Timeline 25
Concluding remarks The KM3NeT TDR is a major milestone for KM3NeT It sums up a more than decennial activity of the european groups Construction of a 5 km 3 detector feasible within a budget of 220 M These activities, together with the success of the pilot projects, put the project on a firm ground Major impact also on the deep-sea sciences Technological solutions developed by KM3NeT have modified the stateof-the-art for deep-sea sciences Strong synergies with the EMSO project for Earth and Sea science activities Collaboration with INGV and IFREMER already active at the Catania and Toulon sites 26