A.Margiotta, SNOW 2006, Stockholm, 6 May 2006

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 – Bolognaon behalf of the NEMO Collaboration

A.Margiotta, SNOW 2006, Stockholm, 6 May 2006

The NEMO collaboration

INFNBari, Bologna, Catania, Genova, LNF, LNS, Napoli, Pisa, RomaUniversitàBari, Bologna, Catania, Genova, Napoli, Pisa, Roma “La Sapienza”

CNRIstituto di Oceanografia Fisica, La SpeziaIstituto di Biologia del Mare, VeneziaIstituto 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

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 km3 -telescope

– development and test of technologies for a km3 -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

A.Margiotta, SNOW 2006, Stockholm, 6 May 2006

Mkn 501

Mkn 421

CRAB

SS433

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

Why a km3 Telescope in the Mediterranean Sea

Several projects and prototypesin the Mediterranean Sea

Mkn 501

RX J1713.7-39

GX339-4SS433

CRAB

VELA

GalacticCentre

the sky from the South Pole

the sky from the Mediterranean Sea

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 : 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)

EXCELLENT ENVIRONMENTAL PROPERTIES MEASURED IN MORE THAN 25 SEA CAMPAIGNS

Average values 2850÷3250 m

Absorption lengthData 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

A.Margiotta, SNOW 2006, Stockholm, 6 May 2006

Possible architecture for a km3 detector

The tower approach:

“Towers” with non homogeneous distribution of sensors

main EO cablemain Junction Box

secondary JB

“tower”

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

140 -180 m

NEMO proposal: 10 junction boxes, 81 towers, 5832 PMTs

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

A.Margiotta, SNOW 2006, Stockholm, 6 May 2006

Tower detector performance

SensitivitySensitivity to point-like sources (E

-2 spectrum)

NEMO 81 towers 140m spaced - 5832 PMTsIceCube 80 strings 125m spaced - 4800 PMTs

NEMO search bin 0.3°IceCube search 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

A.Margiotta, SNOW 2006, Stockholm, 6 May 2006

NEMO Phase 1 project

NEMO Phase 1 LabLong 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 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

Double armed cable2.330 m

Single armed cable20.595 m

North branchNorth branch5.220 m5.220 m

South branchSouth branch5.000 m5.000 m

BU

SN-1Shore stationShore station

NEMO Phase-1

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

Deployedjanuary 2005

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

A.Margiotta, SNOW 2006, Stockholm, 6 May 2006

The NEMO Test Site: a multidisciplinary lab

The ODE stationSN-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)

• ODE (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 )

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

A.Margiotta, SNOW 2006, Stockholm, 6 May 2006

View of the cable landing area

Shore Station

A.Margiotta, SNOW 2006, Stockholm, 6 May 2006

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

The Shore Station building (future project)

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 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.

A.Margiotta, SNOW 2006, Stockholm, 6 May 2006

Some spares slides

A.Margiotta, SNOW 2006, Stockholm, 6 May 2006

Distribution of bioluminescent bacteria

Oce

anD

ata

Vie

w

CT2

D1

E1

F1

M0

L2

LKM3

KM4

SICILY

M0 L2 L KM3 CP5 2 2 0 0 025 3 2 2 0 050 2 2 0 0 075 3 0 0 0 0

100 0 4 0 0 0200 0 0 0 2300 0 2 0 0400 0 2 0 0500 0 2 2 0600 6 0 0 0700 0 2 2 2800 0 3 0 2900 4 2 12 8

1000 0 0 4 41100 0 4 4 01200 2 2 6 21300 0 0 4 21400 0 2 2 01500 0 2 0 22000 0 0 4 22500 0 0 03000 0 0 03300 0 0 0

Autumn 2000 data

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 – labs 70m@450nm Up-going muons

Eµ 103 ÷ 104 GeV

A.Margiotta, SNOW 2006, Stockholm, 6 May 2006

Tower detector performance

SensitivitySensitivity to point-like sources (E

-2 spectrum)

NEMO 81 towers 140m spaced - 5832 PMTsIceCube 80 strings 125m spaced - 4800 PMTs

NEMO search bin 0.5°IceCube search bin 1°

IceCube simulations from Ahrens et al. Astrop. Phys. 20 (2004) 507

simulations performed with ANTARES Coll. software

ReconfigurabilityEffective areas with different element spacing

tower floorspacing spacing

Black line 140 m 40 mRed square 300 m 60 mBlack points 300 m 40 m

A.Margiotta, SNOW 2006, Stockholm, 6 May 2006

The Junction Box

Fibreglass container

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