C.Distefano CRIS 2008 – Salina, September 15 - 20

The KM3Net ConsortiumThe KM3Net Consortium

Istituto Nazionale di Fisica NucleareLaboratori Nazionali del Sud

Towards a km3-scale neutrino Towards a km3-scale neutrino telescope in the Mediterranean Seatelescope in the Mediterranean Sea

C. Distefano

on behalf of the KM3NeT Consortium

C.Distefano CRIS 2008 – Salina, September 15 - 20

What is KM3NeT ?

An acronym for KM3 Neutrino Telescope

A future deep-sea Research Infrastructure hosting a km3 scale neutrino telescope and facilities for associate marine and earth sciences

•Included in the European Roadmap for Research Infrastructures of the ESFRI

A Consortium of 40 institutes from 10 European countries including all the groups that have developed the pilot neutrino telescope projects in the Mediterranean Sea (Antares, Nemo, Nestor)

•Two projects funded by the EU•Design Study (2006-2009): aims at developing a cost-effective design for the construction of a 1 km3 neutrino telescope•Preparatory Phase (2008-2011): preparing for the construction by defining the legal, financial ad governance issues as well as the production plans of the telescope components

C.Distefano CRIS 2008 – Salina, September 15 - 20

Timeline towards construction

C.Distefano CRIS 2008 – Salina, September 15 - 20

Science case

Astroparticle physics with neutrinos• “Point sources”: Galactic and extragalactic sources of

high-energy neutrinos

• The diffuse neutrino flux

• Neutrinos from Dark Matter annihilation

Search for exotics• Magnetic monopoles

• Nuclearites, strangelets, …

Neutrino cross sections at high(est) energies Earth and marine sciences

• long-term, continuous measurements in deep-sea

• marine biology, oceanography, geology/geophysics, …

C.Distefano CRIS 2008 – Salina, September 15 - 20

KM3NeT Conceptual Design Report

Downloadable from the KM3NeT web sitehttp://www.km3net.org/CDR/CDR-KM3NeT.pdf

Downloadable from the KM3NeT web sitehttp://www.km3net.org/CDR/CDR-KM3NeT.pdf

Describes the scientific  objectives, and the concepts  behind the design, construction, and operation of the KM3NeT Research Infrastructure 

Describes the scientific  objectives, and the concepts  behind the design, construction, and operation of the KM3NeT Research Infrastructure 

C.Distefano CRIS 2008 – Salina, September 15 - 20

Design goals

Core process: +N +X at neutrino energies beyond 100 GeV

Lifetime > 10 years without major maintenance, construction and deployment < 4 years

Sensitivity optimized in the TeV-PeV range

Angular resolution 0.1° (for energies above 100 TeV)

Sensitivity to exceed IceCube by “substantial factor”

Some technical specifications:• time resolution better than 2 ns• position of OMs to better than 40 cm accuracy• two-hit separation better than 25 ns• …

C.Distefano CRIS 2008 – Salina, September 15 - 20

Reference detector

Sensitivity studies with a reference detector layout

Geometry:• 15 x 15 vertical detection units

on rectangular grid,horizontal distances 95 m

• each carries 37 OMs, vertical distances 15.5 m

• each OM with21 3’’ PMTs

NOT the finalKM3NeT design!

Effective areaof reference

detector

angular resolution of 0.1° @ 30 TeV

C.Distefano CRIS 2008 – Salina, September 15 - 20

Some proposed geometries

169 NEMO Towers. Square array of 13x13 towers 140m apart. Tower consists of a

sequence of 18 rigid bars, 20m length, 40 m vertically spaced and equipped with 4 10”

PMTs two at each bar end, one down looking and the other horizontally looking. The bars

are orthogonal one with respect to the near one. V~1.9 km3

169 towers 10” PMTs with max QE of 35% at 380nm

169 towers 10” PMTs with max QE of 43% at 390nm

from CDR. Reference detector with 3” PMTs with max QE of 33% at 390nm.

Quality cuts applied to reach an angular resolution of 0.1° @ 30 TeV

C.Distefano CRIS 2008 – Salina, September 15 - 20

Point source sensitivity

Based on muon detection

Factor ~3 more sensitive than IceCube• larger photo-

cathode area• better direction

resolution

Study still needs refinements

C.Distefano CRIS 2008 – Salina, September 15 - 20

Optical Modules

StandardStandard

DirectionalDirectional

With improved photocatode QEWith improved photocatode QE

One large area PMT with segmented photocatodeOne large area PMT with segmented photocatode

C.Distefano CRIS 2008 – Salina, September 15 - 20

Optical Modules

Multi PMTMulti PMT

HybridHybrid

Many small (3’’ or 3.5’’) PMTs in standard glass sphere

Many small (3’’ or 3.5’’) PMTs in standard glass sphere

Use high voltage (~20kV) and send photo electrons on scintillator;detect scintillator light with small standard PMT

Use high voltage (~20kV) and send photo electrons on scintillator;detect scintillator light with small standard PMT

Quasar 370(Baikal)

C.Distefano CRIS 2008 – Salina, September 15 - 20

Mechanical structures

• flexible structure;

• large PMTs in clusters of 2 or more;

• horizontal structures;

• copper/optical readout;

• deployed in compactified “package” and unfurls thereafter

Four options consideredFour options considered

Tower likeTower like

String likeString like

Two full designs were decided to be pursued: Monte Carlo simulations are in progress to choose the best solution

• cable-based designed: one (large) OM per storey (multi-PMT OMs);

• all-optical readout;

• separate mechanical and electro-optical function of cable

• compactified at deployment, unfolding on sea bed

C.Distefano CRIS 2008 – Salina, September 15 - 20

Associated sciences

The KM3NeT infrastructure will serve as a platform for deep-sea and earth sciences

Strong synergy with the deep-sea science community

Associated sciencedevices will be installed at variousdistances aroundneutrino telescope

KM3NeT site in ESONET (European Sea-floor Observatory NETwork) EMSO (European Multi-disciplinary Sea-floor Observatory research

infrastructure)

C.Distefano CRIS 2008 – Salina, September 15 - 20

Candidate sites

Locations of thethree pilot projects:• ANTARES: Toulon• NEMO: Capo Passero• NESTOR: Pylos

All appear to besuitable

Long-term sitecharacterisationmeasurementsperformed and ongoing

Final decision concerning location and single vs multi-site option requiresscientific, technologicaland political input.

C.Distefano CRIS 2008 – Salina, September 15 - 20

Summary and conclusions

The successful experience of the pilot projects demonstrated the feasibility of the km3 underwater high energy neutrino telescope

The KM3NeT consortium is progressing towards the completion of the Technical Design Report (2009) defining the technological solutions for the construction of a km3 telescope in the Mediterranean Sea

The KM3NeT Preparation Phase started aiming at the definition of legal, financial and governance aspects

The KM3NeT detector in the Mediterranean Sea will complement IceCube in its field of view and exceed its sensitivity by a substantial factor

We are working towards a start of construction by 2011