1. A.Margiotta, SNOW 2006, Stockholm, 6 May 2006 Status Report of the NEMO Project (NEutrino Mediterranean Observatory) Towards a km 3 Neutrino Telescope in the Mediterranean Sea Annarita Margiotta, Dipartimento di Fisica e INFN – Bologna on behalf of the NEMO Collaboration

2. A.Margiotta, SNOW 2006, Stockholm, 6 May 2006 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. A.Margiotta, SNOW 2006, Stockholm, 6 May 2006 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 km 3 -telescope –development and test of technologies for a km 3 -telescope –Montecarlo simulations to evaluate the performance of a -telescope depending on environmental parameters and detector layouts to estimate the sensitivity to neutrino point-like sources and HE neutrino diffuse fluxes

4. A.Margiotta, SNOW 2006, Stockholm, 6 May 2006 Mkn 501 Mkn 421 CRAB SS433 Scientific motivations suggest the installation of a km 3 -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 Why a km 3 Telescope in the Mediterranean Sea Several projects and prototypes in the Mediterranean Sea Mkn 501 RX J1713.7-39 GX339-4 SS433 CRAB VELA Galactic Centre the sky from the South Pole the sky from the Mediterranean Sea

5. A.Margiotta, SNOW 2006, Stockholm, 6 May 2006 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. INFN Lab. Nazionali del Sud Capo Passero Light absorption length : L a ≈ 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) EXCELLENT ENVIRONMENTAL PROPERTIES MEASURED IN MORE THAN 25 SEA CAMPAIGNS Average values 2850÷3250 m Absorption length Data taken in: Aug 03 (2) Aug 02 (3) Mar 02 (4) May 02 (2) Dec 99 (2) Dead time: Fraction of time with rate > 200 kHz  PMT: 10”  Thres: ~.5 SPE

6. A.Margiotta, SNOW 2006, Stockholm, 6 May 2006 Possible architecture for a km 3 detector The tower approach: “Towers” with non homogeneous distribution of sensors 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 140 -180 m NEMO proposal: 10 junction boxes, 81 towers, 5832 PMTs

7. A.Margiotta, SNOW 2006, Stockholm, 6 May 2006 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 Optical Modules Electronics container marine aluminium

8. A.Margiotta, SNOW 2006, Stockholm, 6 May 2006 Tower detector performance Sensitivity Sensitivity to point-like sources (E -2 spectrum) NEMO81 towers 140m spaced - 5832 PMTs IceCube80 strings 125m spaced - 4800 PMTs NEMOsearch bin 0.3° IceCubesearch bin 1° IceCube simulations from Ahrens et al. Astrop. Phys. 20 (2004) 507 The simulations have been performed using ANTARES Coll. software NEMO angular resolution

9. A.Margiotta, SNOW 2006, Stockholm, 6 May 2006 NEMO Phase 1 project NEMO Phase 1 Lab Long term tests for: underwater connections, electronics, mechanical structures, optical and acoustic detectors. Multidisciplinary laboratory (on-line underwater seismic station of the Istituto Nazionale di Geofisica e Vulcanologia) Intermediate step towards the underwater km 3 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 Double armed cable 2.330 m Single armed cable 20.595 m North branch 5.220 m South branch 5.000 m BU SN-1 Shore station NEMO Phase-1

10. A.Margiotta, SNOW 2006, Stockholm, 6 May 2006 NEMO Phase-1: scheme and deployment schedule 300 m Mini-Tower compacted Mini-Tower unfurled 15 m Deployment of JB and minitower summer 2006 Junction Box NEMO mini-tower (4 floors, 16 OM) TSS Frame Deployed january 2005

11. A.Margiotta, SNOW 2006, Stockholm, 6 May 2006 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 January 2005 deployment Validation of ROV connection operations System is operative and in data taking Validation of ROV connection operations System is operative and in data taking

12. A.Margiotta, SNOW 2006, Stockholm, 6 May 2006 The NEMO Test Site: a multidisciplinary lab The O DE station SN-1 deep sea station 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 )

13. A.Margiotta, SNOW 2006, Stockholm, 6 May 2006 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. A.Margiotta, SNOW 2006, Stockholm, 6 May 2006 View of the cable landing area Shore Station

15. A.Margiotta, SNOW 2006, Stockholm, 6 May 2006 The Shore Station building (present status) Existing building Total surface = 800 m 2 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 The Shore Station building (future project)

16. A.Margiotta, SNOW 2006, Stockholm, 6 May 2006 Conclusions & perspectives The NEMO Collaboration is working on a long-term R&D program toward the construction of a km 3 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 km 3  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 km 3 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 km 3 detector. KM3NeT activity is starting.

17. A.Margiotta, SNOW 2006, Stockholm, 6 May 2006 Some spares slides

18. A.Margiotta, SNOW 2006, Stockholm, 6 May 2006 Distribution of bioluminescent bacteria Autumn 2000 data

19. A.Margiotta, SNOW 2006, Stockholm, 6 May 2006 Comparison of “tower” and “string” detectors  string-dh_140_20 string-d_125_16  NEMO_140 35 kHz background – l abs 70m@450nm Up-going muons E µ 10 3 ÷ 10 4 GeV

20. A.Margiotta, SNOW 2006, Stockholm, 6 May 2006 Tower detector performance Sensitivity Sensitivity to point-like sources (E -2 spectrum) NEMO81 towers 140m spaced - 5832 PMTs IceCube80 strings 125m spaced - 4800 PMTs NEMOsearch bin 0.5° IceCubesearch bin 1° IceCube simulations from Ahrens et al. Astrop. Phys. 20 (2004) 507 simulations performed with ANTARES Coll. software Reconfigurability Effective areas with different element spacing towerfloorspacing Black line140 m40 m Red square 300 m60 m Black points 300 m40 m

21. A.Margiotta, SNOW 2006, Stockholm, 6 May 2006 The Junction Box Fibreglass container Pressure vessels Electro-optical connections The design decouples the corriosion and pressure resistance problems 1 m Data transmission electronics Power distribution and control system Optical fibre splitters