Paolo Piattelli - KM3NeTIAPS - Golden, 6-8 may 2008 KM3NeT: a deep-sea neutrino telescope in the Mediterranean Sea Paolo Piattelli - INFN/LNS Catania (Italy)

Paolo Piattelli - KM3NeTPaolo Piattelli - KM3NeT IAPS - Golden, 6-8 may 2008IAPS - Golden, 6-8 may 2008

KM3NeT: a deep-sea neutrino telescope in the Mediterranean Sea

Paolo Piattelli - INFN/LNS Catania (Italy)on behalf of the KM3NeT Consortium


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

• A Consortium between the groups/Institutions 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 (2008-2010): preparing for the construction

by defining the legal, financial ad governance issues as well as the pre-production of the telescope components


Timeline towards construction


KM3NeT Conceptual Design Report

Will soon be available on the KM3NeT consortium web sitehttp://www.km3net.org

Will soon be available on the KM3NeT consortium web sitehttp://www.km3net.org

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


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, …


Why in the Mediterranean Sea?

> 25% Visibility

> 75% Visibility

Observed sky region in galactic coordinates assuming efficiency for downwardhemisphere.


Design goals

• Sensitivity to exceed IceCube by “substantial factor”• Core process:

+N +X at neutrino energies beyond 100 GeV

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

• Some technical specifications:– time resolution 2 ns– position of OMs to better than 40 cm accuracy– two-hit separation < 25 ns– false coincidences dominated by marine background– coincidence acceptance > 50%– PM dark rate < 20% of 40K rate


Reference detector

• Sensitivity studies with a common 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


Point source sensitivity

• Based on muon detection

• Factor ~3 more sensitive than IceCube– larger photo-

cathode area– better direction

resolution• Study still needs

refinements


Diffuse fluxes

• Assuming E-2

neutrino energy

spectrum

• Only muonsstudied

• Energy reconstruction not yet included


Configuration studies

• Various geometries and OM configurations have been studied

• None is optimal for all energies and directions• Local coincidence requirement poses important

constraints


KM3NeT CDR contents

1. Introduction

2. Science case

3. The KM3NeT concept

4. Neutrino telescope design goals

5. Pilot projects

6. Site investigations

7. Technical implementation

8. Development plan

9. Project implementation

1. Introduction

2. Science case

3. The KM3NeT concept

4. Neutrino telescope design goals

5. Pilot projects

6. Site investigations

7. Technical implementation

8. Development plan

9. Project implementation

7.1. Optical modules

7.2. Information technology

7.3. Mechanics

7.4. Deep-sea and shore infrastructures

7.5. Deployment

7.6. Calibration

7.1. Optical modules

7.2. Information technology

7.3. Mechanics

7.4. Deep-sea and shore infrastructures

7.5. Deployment

7.6. Calibration


Optical ModulesStandard or directional …Standard or directional …

Segmentation of photo cathode of 10” PMT


Optical Modules… or many small PMTs …… or many small PMTs …

• Basic idea: Use up to 30 small (3’’ or 3.5’’) PMTs in standard sphere

• Advantages: – increased photocathode area– improved 1-vs-2 photo electron

separation better sensitivity to coincidences

– directionality• Prototype arrangements under

study


Optical Modules… or hybrid solutions …… or hybrid solutions …

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

• Advantages:– Very good photo-electron

counting– large angular sensitivity

possible• Prototype development in

CERN/Photonis/CPPM collaboration

Quasar 370(Baikal)


Mechanical structures

- Extended tower structure: NESTOR like, arm length up to 60 m

- Flexible tower structure: NEMO like, tower deployed in compactified “package” and unfurls thereafter

Four options consideredFour options considered

- String structure: Compactified at deployment, unfolding on sea bed

- Cable based concept: one (large) OM per storey, separate mechanical and electro-optical function of cable, compactified deployment

Tower likeTower like

String likeString like

Documents

Paolo Piattelli - KM3NeTIAPS - Golden, 6-8 may 2008 KM3NeT: a deep-sea neutrino telescope in the Mediterranean Sea Paolo Piattelli - INFN/LNS Catania (Italy)