M.Taiuti on behalf of the NEMO Collaboration The NEMO Status Report M.Taiuti on behalf of the NEMO Collaboration Merida, Yucatan, Mexico 30th International Cosmic Ray Conference July 3 - 11, 2007

The NEMO Collaboration INFN Bari, Bologna, Catania, Genova, LNF, LNS, Napoli, Pisa, Roma Universities 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 80 researchers involved

A Northern Telescope for High Energy Neutrinos The small cross section and the expected low neutrino flux require large volume telescope ~ 1 km3 long observation time ~ yrs The atmospheric muon background requires a shielding > 2000 m water equivalent The Mediterranean Sea provides convenient sites NEMO Capo Passero 3400 m NESTOR Pylos 4000 m ANTARES Toulon 2400 m

NEMO R&D Activity Site location NEMO-KM4 80 km off-shore 3500 m depth More than 25 sea campaigns since 1998 NEMO-KM4 80 km off-shore 3500 m depth Catania INFN-LNS TSN TSS NEMO-KM4

NEMO-KM4 Properties High water transparency Data compatible with pure salt water properties No seasonal variations Reduced background, mostly from 40K decay 10” PMT thres. 0.5 p.e. noise rate ~ 30 kHz Bioluminescence almost absent Geologically stable -3000 m

NEMO km3 Conceptual Design

NEMO km3 Conceptual Design Proposed lay-out 10 junction boxes 81 towers 5832 PMTs 140-180 m Tower Secondary JB Electro-optical cable to shore Primary JB

The Expected Performances Simulations show excellent angular resolution and sensitivity NEMO 81 towers 140 m spaced 5832 PMTs ICECUBE 80 strings 125 m spaced 4800 PMTs IceCube simulations from Ahrens et al. Astrop. Phys. 20 (2004) 507  NEMO search bin 0.3°  IceCube search bin 1° Sensitivity to a E-2 neutrino spectrum from a pointlike source

The NEMO Phase-1 Activity North branch 5.220 km Geoseismic station SN-1 station (INGV) Operating since Jan 2005 Single armored cable 20.595 km Double armored cable 2.330 km BU South branch 5.000 km NEMO Phase-1 OnDE acoustic station Operating from Jan 2005 till Dec 2006 NEMO Phase-1 Operating since 16 Dec 2006 Frame Junction Box Jumpers 300m Tower Jumper 300m

The NEMO Junction Box Marine Alum. external frame Transformer Electronics Electro-optical connectors Electro-optical splitting box Successfully deployed Dec. 10, 2006 Glass reinforced plastic container Innovative design to decouple the corrosion and pressure resistance problems

The NEMO Prototype Tower TBM FPM FCM br H OM CTD AB C* ADCP Tower Base Floor 1 Floor 2 Floor 3 Floor 4 Buoy HC 4 floors Length 15 m Vertical spacing 40 m 16 Optical Modules with 10” PMT Acoustic Positioning 2 hydrophones per floor 1 beacon on the tower base Environmental instrumentation 1 compass + tiltmeter in each Floor Control Module CTD (Conductivity-Temperature-Depth) probe on floor 1 C* (attenuation length meter) on floor 2 ADCP (Acoustic Doppler Profiler (including compass) on floor 4

for transportation and deployment The NEMO Tower “Folded” tower ready for transportation and deployment 4 floors Semi-rigid structure provides “easy” assembly, transportation and deployment The 4-floor prototype has been successfully deployed and is operating since Dec. 16, 2006 Successfully deployed Dec. 15, 2006 Successfully connected Dec. 16, 2006

Calibration - Preliminary Results Absolute positioning Long Baseline acoustic positioning system based on five Acoustic Beacons 3 autonomous beacons battery operated 1 beacon on the Junction Box (not operating) 1 beacon on the Tower base Time offset determination network of optical fibres to flash several OMs at one time with fast LED light pulses 350 m 250 m  ≈ 1.5 ns

Preliminary Results Systematics over one month shows good water properties:  baseline rate  burst fraction evaluated as time above 1.2xbaseline  burst fraction evaluated as time above 200 kHz The Tower can recontruct atmospheric muon tracks! January 24 2007 - Run R17 file 1 Event # 366059 13 PMT hit

The NEMO Phase-2 Infrastructures for an -3500 m underwater site 80 km NEMO-KM4 Infrastructures for an -3500 m underwater site Electro-optical cable (50 kW – 20 fibres) Deployment scheduled in summer 2007 Deployment of DC/DC Converter beginning 2008 Shore station in PortoPalo di Capo Passero Building under renovation. Completion beginning 2008 NEMO Tower Deployment forseen by middle 2008 to NEMO-KM4

Conclusions and Perspectives The NEMO Collaboration is working on a long-term R&D program toward a km3 -telescope in the Mediterranean Sea An optimal candidate site has been found: NEMO-KM4 The NEMO Phase-1, aiming to validate the proposed technologies, has been successfully conducted at the Catania Test Site Since Jan. 2005 the geoseismic and acoustic stations are fully operative The Junction Box and the mini-Tower has been deployed at the end of 2006 Data taking is in progress The NEMO Phase-2, aiming to realize the deep sea station at NEMO-KM4, is in progress The deployment of the electro-optical cable is scheduled in 2007 The set-up of the onshore station is in progress The deployment of a full-size tower is foreseen in 2008

Toward the -Telescope EU funded the joint activity for a European-scale Design Study for a km3 -telescope in the Mediterranean Sea KM3NeT: ANTARES-NEMO-NESTOR consortium http://www.km3net.org/ The experience gained will contribute to the advancement of the KM3NeT activities