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Status Report of the NEMO Project ( NE utrino M editerranean O bservatory)

Status Report of the NEMO Project ( NE utrino M editerranean O bservatory). Towards a km 3 Neutrino Telescope in the Mediterranean Sea. Annarita Margiotta, Dipartimento di Fisica e INFN – Bologna on behalf of the NEMO Collaboration. The NEMO collaboration. INFN

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Status Report of the NEMO Project ( NE utrino M editerranean O bservatory)

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  1. Status Report of the NEMO Project(NEutrino Mediterranean Observatory) Towards a km3 Neutrino Telescope in the Mediterranean Sea Annarita Margiotta, Dipartimento di Fisica e INFN – Bologna on behalf of the NEMO Collaboration

  2. The NEMO collaboration INFN Bari, Bologna, Catania, Genova, LNF, LNS, Napoli, Pisa, Roma Università Bari, Bologna, Catania, Genova, Napoli, Pisa, Roma “La Sapienza” CNR Istituto di Oceanografia Fisica, La Spezia Istituto di Biologia del Mare, Venezia Istituto Sperimentale Talassografico, Messina Istituto Nazionale di Geofisica e Vulcanologia (INGV) Istituto Nazionale di Oceanografia e Geofisica Sperimentale (OGS) Istituto Superiore delle Comunicazioni e delle Tecnologie dell’Informazione (ISCTI) More than 70 researchers from INFN and other italian institutes

  3. The goals of the NEMO Collaboration R&D activities devoted to • search, characterization and long term monitoring of a deep sea site for the installation of the Mediterranean km3n-telescope • development and test of technologies for a km3 n-telescope • Montecarlo simulations • to evaluate the performance of a n-telescope depending on environmental parameters and detector layouts • to estimate the sensitivity to neutrino point-like sources and HE neutrino diffuse fluxes

  4. CRAB CRAB VELA SS433 SS433 Mkn 421 Mkn 501 Mkn 501 RX J1713.7-39 GX339-4 Galactic Centre Why a km3n Telescope in the Mediterranean Sea • Scientific motivations suggest the installation of • a km3-telescope in the Mediterranean sea: • complementary to the ICECUBE sky survey • observation of the Galactic center • vicinity to infrastructures • good water quality • good weather conditions for sea operations the sky from the South Pole Several projects and prototypes in the Mediterranean Sea the sky from the Mediterranean Sea

  5. INFN Lab. Nazionali del Sud Absorption length Data taken in: Aug 03 (2) Aug 02 (3) Mar 02 (4) May 02 (2) Dec 99 (2) Capo Passero • PMT: 10” • Thres: ~.5 SPE Dead time: Fraction of time with rate > 200 kHz Average values 2850÷3250 m Site explorations Since 1998 several deep sea sites have been explored in the Mediterranean Sea. optimal site : offshore Capo Passero (Sicily) at about 3500 m depth, 80 km from the shore, wide abyssal plain, far from the shelf break. EXCELLENT ENVIRONMENTAL PROPERTIES MEASURED IN MORE THAN 25 SEA CAMPAIGNS • Light absorption length : La ≈ 70 m @  = 440 nm • compatible with pure water • stable water characteristics constance of the detector effective area • extremely low optical background from bioluminescence • low and stable deep sea water currents (3 cm/s avg., 10 cm/s peak)

  6. secondary JB “tower” main Junction Box main EO cable Possible architecture for a km3 detector Detector architecture issues Reduction of the number of structures to reduce the number of underwater connections and allow operation with a ROV (Remotely Operated Vehicle) Detector modularity The tower approach: “Towers” with non homogeneous distribution of sensors NEMO proposal: 10 junction boxes, 81 towers, 5832 PMTs 140 -180 m 140 -180 m

  7. Optical Modules Electronics container The NEMO tower • semi-rigid 3D structure. • - easy deployment and recovery. • modular structure composed by a sequence of bars, perpendicular to each other, interconnected by tensioning cables. • full height 750 m. • - power and data trasmission cables separated from the tensioning ones. • bar length 15 m; • bar spacing 40 m; • 150 m between seabed and first tower floor; • 4 PMTs per floor (2 downward looking and 2 horizontally looking A tower floor A “folded” tower for transportation and deployment marine aluminium

  8. Tower detector performance NEMO angular resolution Sensitivity Sensitivity to point-like sources (En-2 spectrum) IceCube simulations from Ahrens et al. Astrop. Phys. 20 (2004) 507 NEMO 81 towers 140m spaced - 5832 PMTs IceCube 80 strings 125m spaced - 4800 PMTs NEMO search bin 0.3° IceCube search bin 1° The simulations have been performed using ANTARES Coll. software

  9. SN-1 Shore station North branch 5.220 m Double armed cable 2.330 m Single armed cable 20.595 m BU South branch 5.000 m NEMO Phase-1 NEMO Phase 1 project • Intermediate step towards the underwater km3 detector • Validation of the technological solutions proposed • Detector subsystem including the critical components : the tower and the Junction Box • Test Site : an electro-optical submarine cable + a shore station • Infrastructures at 2000 m depth already realized 25 km offshore Catania • Project completely funded by INFN and MIUR • Realization of main components and integration of the detector almost completed. Project completion: 2006 Multidisciplinary laboratory (on-line underwater seismic station of the Istituto Nazionale di Geofisica e Vulcanologia) NEMO Phase 1 Lab Long term tests for: underwater connections, electronics, mechanical structures, optical and acoustic detectors.

  10. NEMO Phase-1: scheme and deployment schedule Mini-Tower unfurled NEMO mini-tower (4 floors, 16 OM) Deployedjanuary 2005 Deployment of JB and minitower summer 2006 Junction Box TSS Frame 300 m Mini-Tower compacted 15 m

  11. January 2005 deployment Deployment of two cable termination frames equipped with Electro-optical wet mateable connectors Deployment and connection of an acoustic detection station Deployment and connection of the SN-1 seismic and environmental monitoring station Validation of ROV connection operations System is operative and in data taking

  12. The NEMO Test Site: a multidisciplinary lab • Submarine Network-1, a deep sea station for on-line seismic and environmental monitoring by INGV. The NEMO-SN1 is the first active node of ESONET (European Seafloor Observatory NETwork) • ODE (Ocean noise Detection Experiment), on-line deep sea acoustic signals monitoring (4 hydrophones 30 Hz - 40 kHz  measurement of background noise for neutrino acoustic detection ) The ODE station SN-1 deep sea station

  13. The NEMO Phase 2 project A deep sea station on the Capo Passero site • OBJECTIVES • Realization of an underwater infrastructure at 3500 m on the Capo Passero site • Test of the detector structure installation procedures at 3500 m • Installation of a 16 storey tower • Long term monitoring of the site • INFRASTRUCTURE UNDER CONSTRUCTION • Shore station in Portopalo di Capo Passero • 100 km electro optical cable • Underwater infrastructures • STATUS • Purchase of the electro-optical cable (>50 kW) under way • A building located inside the harbour area of Portopalo has been acquired. It will be renovated to host the shore station • Project completion planned in 2007

  14. View of the cable landing area Shore Station

  15. The Shore Station building (future project) The Shore Station building (present status) Existing building Total surface = 800 m2 • Building acquired • Renovation project defined and under approval procedure by the “Sovraintendenza ai Beni Culturali” • Start of construction work for renovation in 2006 • Station completion in 2007

  16. Conclusions & perspectives • The NEMO Collaboration is working on a long-term R&D program toward the construction of a km3 neutrino telescope in the Mediterranean Sea • The NEMO Phase 1 project is ongoing at an underwater test site offshore Catania: • validation of the proposed technologies for the realization and installation of the km3 • January 2005: full success with the deployment of 2 cable termination frames • installation of geoseismic and acoustic stations confirms that ROV technology is exploitable for a km3 detector • infrastructure (cable to shore, shore station) ready • junction box and a reduced-size tower to be deployed in 2006 • The NEMO Phase 2 project has started at the Capo Passero site: • work to equip the onshore station started • electro-optical cable purchase is under way • full-size tower (16 floors, 64 PMTs) to be deployed in 2007 • NEMO takes part in the European Design Study activity (KM3NeT) for a Mediterranean km3 detector. KM3NeT activity is starting.

  17. Some spares slides

  18. Distribution of bioluminescent bacteria Autumn 2000 data

  19. Comparison of “tower” and “string” detectors Up-going muons 35 kHz background – labs 70m@450nm Eµ 103 ÷ 104 GeV  string-dh_140_20 string-d_125_16 NEMO_140

  20. Tower detector performance Reconfigurability Effective areas with different element spacing Sensitivity Sensitivity to point-like sources (En-2 spectrum) IceCube simulations from Ahrens et al. Astrop. Phys. 20 (2004) 507 tower floor spacing spacing Black line 140 m 40 m Red square 300 m 60 m Black points 300 m 40 m NEMO 81 towers 140m spaced - 5832 PMTs IceCube 80 strings 125m spaced - 4800 PMTs simulations performed with ANTARES Coll. software NEMO search bin 0.5° IceCube search bin 1°

  21. Data transmission electronics • Power distribution and control system • Optical fibre splitters Electro-optical connections Pressure vessels Fibreglass container The design decouples the corriosion and pressure resistance problems 1 m The Junction Box

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