R. Coniglione INFN-LNS TEV PA Paris July 2010 KM3NeT: a project for an underwater cubic kilometre neutrino telescope R. Coniglione INFN-LNS for KM3NeT collaboration The KM3NeT consortium aims at developing a deep- sea research infrastructure in the Mediterranean Sea. The construction of a multi-cubic-kilometre Cherenkov telescope for neutrinos with energies above 100 GeV is the principal KM3NeT goal Introduction Main objectives The KM3NeT Technical Design Report Telescope physics performance New developments Summary

R. Coniglione INFN-LNS TEV PA Paris July 2010 KM3NeT and the international context High energy neutrino telescope world map ANTARES, NEMO, NESTOR joined efforts to prepare a km3-size neutrino telescope in the Mediterranean Sea: KM3NeT IceCube IC79 taking data since 2010 IC59 data analysis started Antares Taking data in its final configuration (12 lines) since may lines data analyzed and ready to be published

R. Coniglione INFN-LNS TEV PA Paris July 2010 The KM3NeT consortium  The KM3NeT consortium includes 40 Institutes from 10 European Countries (Cyprus, France, Germany, Greece, Ireland, Italy, The Netherlands, Rumania, Spain, U.K.)  KM3NeT Design Study (DS) -> define the telescope design and outline the main technological options Approved under the 6° FP (funded by EC for the period ) Conceptual Design Report (CDR) published in 2008 ( Activity of DS culminated with the publication of the Technical Design Report (TDR) that outlines the main technological options for the construction, deployment and maintenance of a deep sea neutrino telescope ( (TDR contents frozen in November 2009)  KM3NeT Preparatory Phase (PP) -> 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 EC for the period )

R. Coniglione INFN-LNS TEV PA Paris July 2010 Neutrino will provide unique info on High Energy Universe on the origin of UHE cosmic rays (astrophysics, cosmology and particle physics) on the high energy gamma production mechanism (hadronic and/or leptonic) on the source dense inner core Neutrino observation can be connected with the observed gamma fluxes for sources with low matter density while new high density sources can be observed Motivation for the high energy neutrino detection

R. Coniglione INFN-LNS TEV PA Paris July 2010 KM3NeT main objectives Central physics goals: -Investigate neutrino “point sources” in the TeV energy regime galactic ->Supernova Remnants, Microquasars… extragalactic -> Active Galactic Nuclei, Gamma Ray Bursts -Complement IceCube field of view -Exceed IceCube sensitivity Other important physics items: - High energy diffuse neutrino flux detection - Indirect search of Dark Matter - Neutrino particle physics aspects - Exotics (Magnetic Monopoles, Lorentz invariance violation, …) Interdisciplinary research - geophysics, oceanography, marine biology, … Implementation requirements: Construction time ≤5 years Operation over at least 10 years

R. Coniglione INFN-LNS TEV PA Paris July 2010 KM3NeT sky view 2  downward coverage assumed >75% >25%  KM3NeT complements the IceCube field of view  KM3NeT observes a large part of the sky (~3.5  ) At the Mediterranean sea latitude the source visibility can be less than 24h

R. Coniglione INFN-LNS TEV PA Paris July 2010 Neutrino detection principle  Interaction point  Upward-going neutrinos interact in rock or water (  is the golden channel for astronomy) Emerging charged particles (in particular muons) produce Cherekov light in water at 43° with respect to the neutrino direction Light detection by array of photomultipliers From photon arrival times and PMT positions is possible to reconstruct the muon direction Detection volume of the order of 5 km 3 to exceed IceCube sensitivity by a substantial factor 43° cc

R. Coniglione INFN-LNS TEV PA Paris July 2010 Technical items The telescope consists of 3D array of photo-sensors supported by vertical structures (DU) connected to a seabed with a cable network The construction of a deep sea neutrino telescope is technically highly challenging Very high pressure Environment chemically aggressive Deployment operation safe, robust and precise Technical items Optical Modules Front-end electronics 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 Requirements Cost-effective Reliable Producible Easy to deploy

R. Coniglione INFN-LNS TEV PA Paris July 2010 Other issues addressed in the Design Study Site characterization: Characterization of the site and measure of the water properties optical background, currents, sedimentation, water properties (absorption and scattering lengths….) Simulation: -Detector performances (sensitivity and discovery fluxes) optimizing the detector parameters - Earth and Sea science requirements: Define the infrastructure needed to implement multidisciplinary science nodes (marine biology, geology/geophysics, oceanography, environmental studies, alerts, …)

R. Coniglione INFN-LNS TEV PA Paris July 2010 Optical modules Two alternative solutions in the TDR for OM 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

R. Coniglione INFN-LNS TEV PA Paris July 2010 Optical modules Two alternative solutions in the TDR for OM Single-PMT Optical Module Advantages Multi-PMT Optical Module Advantages photocathode surface greater than 3 8-inch PMTs insensitive to the Earth’s magnetic field -> no mu-metal shielding single-photon from multi-photon hits separation information on the arrival direction of Cherenkov light-> better track reconstruction large angular acceptance good timing response well known technology

R. Coniglione INFN-LNS TEV PA Paris July 2010 Front-end electronics: Time-over-Threshold Common solutions in the TDR for the front-end electronics

R. Coniglione INFN-LNS TEV PA Paris July 2010 Detection Units Three alternative solutions in the TDR for DUs 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

R. Coniglione INFN-LNS TEV PA Paris July 2010 Deployment strategy Common deployment strategy in the TDR Main deployment concepts Compact package Self unfurling Connection to seabed network by Remotely Operated Vehicle Spherical deployment structure for string with single OM with multi-PMT The packed flexible tower (20 storey) Successful deployment test in February 2010 Successful deployment test in December 2009

R. Coniglione INFN-LNS TEV PA Paris July 2010 KM3NeT: an artistic view Primary Junction boxSecondary Junction boxes Detection Units Electro-optical cable

R. Coniglione INFN-LNS TEV PA Paris July 2010 Simulations: optimization studies Bar length optimization Optimization of Detection Unit separation Examples for the flexible tower Low energy region 100GeV<E <500 GeV Quality cuts applied   -  rec ~ 2° (close to the  -  ) Point like sources 3TeV<E <100 TeV Quality cuts applied   -  rec ~ 0.4° (close to the search cone radius) Diffuse flux studies & GRB E >100 TeV No quality cuts applied   -  rec  0.9° ratio of the effective area relative to 3mratio of the effective area relative to 100m

R. Coniglione INFN-LNS TEV PA Paris July 2010 Simulations: optimization studies Sensitivity ratio for point like source - 1 year –  =-60° Flexible tower 180 m preferred DU distance Final bar length choice is a compromise between physical performance and technical constraints Bar length Detection unit separation

R. Coniglione INFN-LNS TEV PA Paris July 2010 Sensitivity to point source (flux  E -2 ) vs declination for one year of observation time Full KM3NeT detectors made of the three DU configurations at the same cost were considered in the simulations Similar sensitivity per euro for the three configurations Black Slender string Red Flexible tower Green Triangles A detector with a total cost of about 220M€ is required to surpass the performance of IceCube by a substantial factor Simulation results concept Number of DU for 220M€ Flexible tower with 6 8” PMT per bar 20 bars 310 (2x154) Slender strings 20 floors with 1 multi-PMT per floor 620 (2X310) Triangles 6 8” PMT per floor 20 floors 254 (2x127)

R. Coniglione INFN-LNS TEV PA Paris July 2010 KM3NeT: effective area & resolution ☐ Quality Cuts applied Quality Cuts optimized for sensitivity Neutrino effective area Detector resolution Median of   rec Kinematic s     median of the   distribution

R. Coniglione INFN-LNS TEV PA Paris July 2010 KM3NeT: sensitivity & discovery KM3NeT sensitivity 90%CL KM3NeT discovery 5  50% IceCube sensitivity 90%CL IceCube discovery 5  50% 2.5÷3.5 above sensitivity flux. (extrapolation from IceCube 40 string configuration) binned method unbinned method | Observed Galactic TeV-  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 fluxes for point like sources with a E -2 spectrum for 1 year of observation time

R. Coniglione INFN-LNS TEV PA Paris July 2010 Developments after the TDR In the recent months developments towards a technology convergence on a unique design “bar” option with horizontal extent and 6 8-inch PMTs –Optimised design and plan for extensive deployment tests defined Study of the advantages offered by a “hibrid” solution –DU with horizontal extent –Multi-PMT Optical Module Multi-PMT option –Needs validation of technology and integration procedures –Common development of the multi-PMT Optical Module and its implementation on the tower –Optimization of simulation of the detector performance ongoing

R. Coniglione INFN-LNS TEV PA Paris July 2010 Flexible tower DU with 6 13” spheres: stacking concept Height = 1.43 m

R. Coniglione INFN-LNS TEV PA Paris July 2010 Flexible tower DU with 2 17” OM: preliminary storey design

R. Coniglione INFN-LNS TEV PA Paris July 2010 Summary A design for the KM3NeT neutrino telescope complementing the IceCube field of view and surpassing it in sensitivity by a substantial factor is presented The required sensitivity can be achieved within an overall budget of ≈ 250 M€ Staged implementation, with increasing discovery potential, is technically possible Convergence process toward a unique technical design under way Development plan for qualification of a pre-production model of the detection unit defined Remaining technical decisions have to be taken within the next spring Readiness for construction expected at the end of the Preparatory Phase (march 2012) Installation could start in 2013 and data taking soon after

R. Coniglione INFN-LNS TEV PA Paris July 2010 The end

R. Coniglione INFN-LNS TEV PA Paris July 2010 Simulations: optimization studies Sensitivity ratio for point like source - 1 year –  =-60° Flexible tower 180 m preferred DU distance Final bar length choice is a compromise between physical performance and technical constraints Bar length Detection unit separation  =-2.2  =-2

R. Coniglione INFN-LNS TEV PA Paris July 2010 Theta versus declination Mediterranean sea latitude  36°  = Above the horizon Below the horizon Near the horizon the effect of Earth absorption is reduced for high energy neutrinos