Status of KM3NeT (Detector Design Optimisations) Christopher Naumann, CEA Saclay – IRFU / SPP for the KM3NeT consortium 44 th Reconcontres de Moriond, La Thuile, Italy, 1 st -8 th February 2009

CEA DSM Irfu "Status of KM3NeT Design Optimisations", 44th Recontres de Moriond, 2/ Christopher Lindsay Naumann 2 Physics Motivation: Neutrinos from Astrophysical Sources TeV neutrinos by-product in cosmic accelerators:TeV neutrinos by-product in cosmic accelerators: Gamma Ray Bursts “smoking gun” for hadronic acceleration probe for hidden sources: no magnetic deflection, (nearly) no absorption  new window to astrophysics! supernova remnants Active galactic nuclei (AGN) p/A + p/     +...      e e

CEA DSM Irfu "Status of KM3NeT Design Optimisations", 44th Recontres de Moriond, 2/ Christopher Lindsay Naumann 3 Existing Neutrino Telescopes Lake Baikal Lake Baikal, Siberia: Baikal Deep Underwater Neutrino Telescope (1993+) South Pole: AMANDA (1996+) IceCube (2005+) under construction, first km 3 size detector Mediterranean: ANTARES (completed summer 2008) R&D project NEMO, NESTOR no km 3 sized detector in the North ! South Pole Mediterranean

CEA DSM Irfu "Status of KM3NeT Design Optimisations", 44th Recontres de Moriond, 2/ Christopher Lindsay Naumann 4 KM3NeT – a km 3 neutrino telescope in the Mediterranean Consortium of ~40 laboratories from 10 European countries Combines Mediterranean projects ANTARES, NEMO and NESTOR  neutrino astronomy on a new scale + earth and sea science develop adesign –Design Study ( ): “develop a cost-effective design for the construction of a 1 km 3 neutrino telescope” prepararationconstruction pre-production telescope components –Preparatory Phase ( ) : “prepararation for construction by defining the legal, financial and governance issues, as well as the pre-production of the telescope components” co-financed by E.U. (FP6 and FP7)

CEA DSM Irfu "Status of KM3NeT Design Optimisations", 44th Recontres de Moriond, 2/ Christopher Lindsay Naumann 5 The KM3NeT site Toulon Capo Passero Pylos candidate sites three candidate sites in the Mediterranean depth m different water properties decision pending sky coverage > 2  sr complementary to IceCube (but overlap) Galactic centre HESS sources KM3NeT

CEA DSM Irfu "Status of KM3NeT Design Optimisations", 44th Recontres de Moriond, 2/ Christopher Lindsay Naumann 6 KM3NeT – Design Goals complementary to IceCube and with improved physics sensitivity −angular resolution 0.1° above 30TeV −focus energy range 1 TeV – 1 PeV −good muon background suppression design goals and technical options formulated in CDR CDR-KM3NeT.pdf  need O(10 4 ) optical modules, instrumented volume O(1km 3 ) (~50 × ANTARES). physics simulationinformation tech. hardware developmentrisk assessment deep sea infrastructureassociated science management… ISBN

CEA DSM Irfu "Status of KM3NeT Design Optimisations", 44th Recontres de Moriond, 2/ Christopher Lindsay Naumann 7  42° sea floor interaction Cherenkov light from  3D PMT array reconstruct muon (neutrino) trajectory from position and timing of hits Neutrino Telescope: Detection Principle efficiency and quality depend strongly on PMT distribution !

CEA DSM Irfu "Status of KM3NeT Design Optimisations", 44th Recontres de Moriond, 2/ Christopher Lindsay Naumann 8 Geometry optimisation studies Detector optimisation: a multidimensional problem ! find detector which is… 1.optimised for physics goals 2.technically and financially feasible 3.can be built on short time scale! − ”physics”: neutrinos, atmospheric , optical background − “hardware”: detector characteristics, water properties use return of experience from ANTARES, NEMO and NESTOR! sea floor layout type of detection units detector site (water properties, depth) trigger, reconstruction readout data flow …

CEA DSM Irfu "Status of KM3NeT Design Optimisations", 44th Recontres de Moriond, 2/ Christopher Lindsay Naumann 9 Optimisation: Possible detector layouts square / hexagonal grids, rings, clusters large range of horizontal and vertical distances −None ideal for all energies and directions −optimum distances  energy range, site optimisation ongoing !

CEA DSM Irfu "Status of KM3NeT Design Optimisations", 44th Recontres de Moriond, 2/ Christopher Lindsay Naumann 10 Optimisation: Detection Units investigate different types of detection units: “strings” (1D) or “towers” (3D) single large or many small PMTs directional PMTs, hybrid photodetectors,… multi-PMT directional PMT large PMT cable, multi-PMT 3D tower string, 10” PMTs ~10m (schematic) hybrid PD → affect detector characteristics! → included in simulation

CEA DSM Irfu "Status of KM3NeT Design Optimisations", 44th Recontres de Moriond, 2/ Christopher Lindsay Naumann 11 Example results: Reference detector (CDR) Geometry: “string type” 15 x 15 strings, rectangular grid, horizontal distances 95 m 37 storeys, distance 15.5m storey: single OM with 21 3’’ PMTs neutrino effective area (defines event rate) ~30 × ANTARES ! representative detector design basis for sensitivity studies NOT the final KM3NeT design! O(10 2 ) m 2 E ≥ 100TeV 2×10 -1 m 2 at 1 TeV ANTARES simulation km 3

CEA DSM Irfu "Status of KM3NeT Design Optimisations", 44th Recontres de Moriond, 2/ Christopher Lindsay Naumann 12 Point source limits, reference detector limits better than ANTARES and IceCube: better angular resolution and larger photocathode area  within reach of model predictions for several known CR sources ! preliminary preliminary! point source limits: source flux E -2 background: atmospheric only 90 % CL T meas = 1 year x 30

CEA DSM Irfu "Status of KM3NeT Design Optimisations", 44th Recontres de Moriond, 2/ Christopher Lindsay Naumann 13 Diffuse fluxes, reference detector ~ factor 10 below Waxman-Bahcall bound  reach area interesting for neutrino searches! KM3NeT W-B IceCube ANTARES atmospheric flux (Bartol) diffuse flux sensitivity: spectrum E -2 only  CC MC energy

CEA DSM Irfu "Status of KM3NeT Design Optimisations", 44th Recontres de Moriond, 2/ Christopher Lindsay Naumann 14 Dark matter sensitivity (reference detector)  Detectability: -Blue: ANTARES -Green: KM3NeT -Red: None of them preliminary values, need for further optimisation ! Scan of mSUGRA parameter space Focus on points compatible with WMAP data significant increase over ANTARES sensitivity

CEA DSM Irfu "Status of KM3NeT Design Optimisations", 44th Recontres de Moriond, 2/ Christopher Lindsay Naumann 15 Conclusions and Outlook KM3NeT consortium in the process of designing a km 3 size detector for the MediterraneanKM3NeT consortium in the process of designing a km 3 size detector for the Mediterranean large number of options for layout and technology studied, narrowing parameter space downlarge number of options for layout and technology studied, narrowing parameter space down first values for sensitivity (non-optimised)first values for sensitivity (non-optimised)  Conceptual Design Report ready (April 2008) Next step: Finalisation of storey and detector layoutNext step: Finalisation of storey and detector layout  Technical Design Report (TDR) end of 2009 construction of working prototypesconstruction of working prototypes Start of construction foreseen 2011Start of construction foreseen 2011 Thank you !

CEA DSM Irfu "Status of KM3NeT Design Optimisations", 44th Recontres de Moriond, 2/ Christopher Lindsay Naumann 16 Back-Up

CEA DSM Irfu "Status of KM3NeT Design Optimisations", 44th Recontres de Moriond, 2/ Christopher Lindsay Naumann 17 Current Situation The universe in TeV neutrinos as of February 2009 It’s high time to change this ! ?

CEA DSM Irfu "Status of KM3NeT Design Optimisations", 44th Recontres de Moriond, 2/ Christopher Lindsay Naumann 18 KM3NeT and IceCube Southern Hemisphere South Pole ice: ≈ no optical background long absorption length shorter scattering length Northern Hemisphere Sea water: optical background shorter absorption length long scattering length low E threshold limited angular resolution higher E threshold better angular resolution complementary sky coverage