Neutrino Astronomy with KM3NeT

The KM3NeT physics case

What happened so far

The KM3NeT Conceptual Design Report

The Preparatory Phase: Towards implementation

Vulcano Workshop 2008: Frontier Objects in Astrophysics and Particle PhysicsVulcano, Eolian Islands, Italy, May 25-31, 2008

Uli KatzECAP / Univ. Erlangen

30.05.2008

30.05.2008 U. Katz: KM3NeT 2

The Neutrino Telescope World Map

ANTARES + NEMO + NESTORjoin their efforts to prepare

a km3-scale neutrino telescope in the Mediterranean

KM3NeT Design Study

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What is KM3NeT ?

Future cubic-kilometre scale neutrino telescope in the Mediterranean Sea

Exceeds Northern-hemisphere telescopes by factor ~50 in sensitivity

Exceeds IceCube sensitivity by substantial factor

Focus of scientific interest: Neutrino astronomy in the energy range 1 to 100 TeV

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Particle Propagation in the Universe

Photons: absorbed on dust and radiation;Protons/nuclei: deviated by magnetic fields, reactions with radiation (CMB)

1 parsec (pc) = 3.26 light years (ly)

gammas (0.01 - 1 Mpc)

protons E>1019 eV (100 Mpc)

protons E<1019 eV

neutrinos

Cosmic accelerator

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The KM3NeT Field of View

2 downward sensitivity assumed

Located inMediterranean visibilityof givensource canbe limitedto less than 24h per day

> 75%> 25%

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Science Case Revisited

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, …

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Point Source Sensitivity

Based on muon detection

Why factor ~3 more sensitive than IceCube?- larger photo-

cathode area

- better direction resolution

Study still needs refinements

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Flux Predictions from Measurements

1 error bands include systematic errors (20% norm., 10% index & cut-off)

mean atm. flux(Volkova, 1980,

Sov.J.Nucl.Phys., 31(6), 784)

Vela X (PWN)

expected neutrino flux –

in reach for KM3NeT

measured-ray flux (H.E.S.S.)

A.Kappes et al., astro-ph 0607286

Note: hadronicnature of Vela X

not clear!

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Another Case: SNR RXJ1713.7-3946

Good candidate for hadronic acceleration.

Expected signal well related to measured flux, but depends on energy cutoff.

Few events/year over similar back-ground (1km3).

KM3NeT sensitivity in the right ballpark!

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Potential Galactic Sources

The accelerators of cosmic rays- Supernova remnants- Pulsar wind nebulae- Micro-quasars- …

Interaction of cosmic rays with interstellar matter

- Possibly strong signal if CR spectrum harder in Galactic Centre than on Earth (supported by recent MILAGRO results)

Unknown sources – what are the H.E.S.S.”TeV gamma only” objects?

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Potential Extragalactic Sources

AGNs- Models are rather diverse and uncertain- The recent Auger results may provide an upper limit /

a normalisation point a UHE - Note : At some 100 TeV the neutrino telescope field of

view is restricted downwards ( absorption), but starts to be significant upwards.

Gamma ray bursts- Unique signature: Coincidence with gamma

observation in time and direction- Source stacking possible

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Diffuse Fluxes

Assuming E-2

neutrino energy spectrum

Only muonsstudied

Energy reconstruction not yet included

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Dark Matter Sensitivity

Scan mSUGRAparameter spaceand calculateneutrino flux foreach point

Focus on pointscompatible withWMAP data

Detectability:

- Blue: ANTARES

- Green: KM3NeT

- Red: None of them

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KM3NeT: From the Idea to a Concept

11/2002 4/20089/20062/20069/20053/2004

Firstconsultations of

ANTARES, NEMOand NESTOR

KM3NeT onESFRI Roadmap

KM3NeT on ESFRIList of Opportunities

Design Studyproposal submitted

The KM3NeTConceptual

Design Report

Begin of Design Study

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Major Achievements to Date

Science & technology- Successful prototype deployments by NEMO and NESTOR

- Installation and operation of ANTARES

A large deep-sea neutrino telescope is feasible!

Politics & funding- Endorsement by ESFRI and ApPEC

- Funding through EU: Design Study, Preparatory Phase

- Funding through national authorities:pilot projects, commitments for KM3NeT

Towards construction - Strong collaboration

- Design concepts in CDR

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ANTARES: Progress

14.5m

100 m

25 storeys,348 m

Junction Box

~70 m

String-based detector; Downward-looking

photomultipliers (PMs),axis at 45O to vertical;

2500 m deep. Currently taking data with 10

lines, completion imminent.37 days with 5 lines

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The KM3NeT Conceptual Design Report

Presented to public atVLVnT0 workshop in Toulon, April 2008

Summarises (a.o.)

- Physics case

- Generic requirements

- Pilot projects

- Site studies

- Technical implementation

- Development plan

- Project implementation

available on www.km3net.org

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The 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

This is NOT the final

KM3NeT design!

Effective areaof reference

detector

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Configuration Studies

Various geometries and OM configurations have been studied

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

important constraints on OM pattern

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KM3NeT 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

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Technical Implementation

Photo-sensors and optical modules

Data acquisition, information technology and electronics

Mechanical structures

Deep-sea infrastructure

Deployment

Calibration

Associated science infrastructure

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A segmented anode and a mirror system allow for directional resolution

First prototypes produced

A standard optical module, as used in ANTARES

Typically a 10’’ PMT in a 17’’ glass sphere

Optical Modules: Standard or Directional

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… or Many Small Photomultipliers …

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

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… 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, high quantum eff.

- large angular sensitivity possible

Prototype development in CERN/Photonis/CPPM collaboration

Quasar 370(Baikal)

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Photocathode News

New photocathode developments by two companies (Hamamatsu, Photonis)

Factor 2 in quantum efficiency factor 2 in effective photocathode area!

Major gain in neutrino telescope sensitivity!

Hamamatsu

Photonis

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Mechanical Structures

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

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

3. String structure: Compactified at deployment, unfolding on sea bed

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

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The Associated Science Installation

Associated sciencedevices will be installed at variousdistances aroundneutrino telescope

Issues:- interfaces

- operation withoutmutual interference

- stability of operationand data sharing

Synergy effects

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The Candidate Sites Locations of the

three pilot projects:- ANTARES: Toulon- NEMO: Capo Passero- NESTOR: Pylos

All appear to besuitable

Long-term sitecharacterisationmeasurementsperformed and ongoing

Site decision requiresscientific, technologicaland political input

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Site Characterisation: An Example

Important parameter:water transparency

Pylos(460 nm)

Capo Passero

Also: optical background,sea currents, sedimentation,

biofouling, radioactivity, …

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The KM3NeT Preparatory Phase

“Preparatory Phase”: A new EU/FP7 funding instrument restricted to ESFRI projects.

KM3NeT proposal endorsed, funded with 5 M€,coordinated by Emilio Migneco / LNS Catania

3-year project, 3/2008 – 2/2011; kick-off meeting in Catania, 10-13 March 2008

Major objectives:- Initiate political process towards convergence

(includes funding and site selection/decision)- Set up legal structure and governance- Strategic issues: New partners, distributed sites, extendibility- Prepare operation organisation & user communities- Organise pre-procurement with commercial partners- Next-step prototyping

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Timeline Towards Construction

Note: “Construction” includes the final prototyping stage

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Summary

Neutrinos would (and will) provide very valuable astrophysical information, complementary to photons and charged cosmic rays

Exploiting the potential of neutrino astronomy requires cubic-kilometre scale neutrino telescopes providing full sky coverage

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