KM3NeT -a next generation neutrino telescope in

the Mediterranean Sea

Presented at TAUP 2007 - Tenth International Conference on Topics in Astroparticle and Underground Physics ; September 11-15, 2007; Sendai (Japan)

For the KM3NeT Collaboration

Petros A. Rapidis

National Center for Scientific Research “Demokritos”, Athens, Greece and

NESTOR Experiment Collaboration

What is KM3NeT ?

An acronym for cubic kilometer sized (km3) sea water neutrino telescope. It is a European Consortium funded by EC FP6* whose goal is a DesignStudy for a:

Deep Sea Facility in the Mediterranean for Neutrino Astronomy and Associated Sciences - started February 2006

Associated Sciences: Oceanography Marine Biology Environmental Sciences Geology and Geophysics

* 6th Framework Program of the European Commission to support the ‘European Research Area’

Comprises of 37 institutes from:

Cyprus, France, Germany, Greece, Ireland,

Italy, The Netherlands, Spain, and The United Kingdom

… other groups are welcomed !

KM3NeT consortiumKM3NeT consortium

+ + +..

Builds upon the experience of the past ‘pilot’ projects :

Not to forget DUMAND, BAIKAL, and other (frozen) water based projects.

• Design study: 2006-2009– Technical Design Report

• Preparatory phase: 2008-2011 (proposal submitted)– Political convergence (site)– Commitment for construction of funding agencies/ministries– Governance and legal structure– System prototype– Tendering procedures

• Construction phase: 2010-2013– Build 1 km3 detector

Feb 2006 Jan 2008 Mid 2010

CDR TDR

Design Study Design Study

Preparatory PhasePreparatory Phase

Production model for detection unit

Financial plan

Assembly model

ConstructionConstruction

Tenders

Now

Draft KM3NeT timelineDraft KM3NeT timeline

Targeted budget:Targeted budget:220-250 M€ (ESFRI roadmap) !!220-250 M€ (ESFRI roadmap) !!

KM3NeT Design Study objectives

• Effective volume 1 km3

• Angular resolution for muons: 0.1o (for neutrino energies 10 TeV)

• Energy threshold: few 100 GeV (~100 GeV when pointing)

• Sensitivity to all neutrino flavours, CC/NC reactions

• Field of view: close to 4 for high energies

Outline of the rest of the talk :

Pulsar Wind Nebula

Supernova Remnants

RX J1713.73946HESS

Microquasars

Gamma Ray Bursts

(GRB970228, BeppoSax)Active Galactic Nuclei

•Why ? (what is the physics case)

•The way towards a km3 detector

•The KM3NeT Design Study

•Where are we now?Cosmic Neutrino Sources

Galactic:

Extra -Galactic:

We live in a truly active universe ! (as HESS has emphasized!)

Directional aspects of neutrino telescopes

Muon neutrinos for identification of individual sources (need good angular resolution)

Muons can penetrate several km of water if E ν > 1 TeV

⇒ huge background from atmospheric ν, hence the need for a

deep underwater site

Sensitivity for sources “above” much reduced

needs either very high energies

or short transients (e.g., GRBs)

Neutrino astronomy

Mkn 501

RX J1713.7-39

GX339-4

SS433

CRAB

GalacticCentre

VELA

Mkn 501

Mkn 421

CRAB

SS433

Antartica Mediterranean Sea

→ We need Northern ν telescopes to cover the Galactic Plane

Example: Vela X (PWN)

mean atm. flux (Volkova, 1980, Sov.J. Nucl.Phys., 31(6), 784

Measured γ ray

Flux (H.E.S.S.)

A. Kappes et al., ApJ 656:870, 2007 (astroph/0607286)

expected

neutrino flux –

Sensitivity for KM3NeT

ν Flux Predictions from γ Ray Measurements

Such calculations show that we need km3scale detectors

Presentations earlier in this session –

• V. Bertrand, Status report on the ANTARES Neutrino Telescope • P. Sapienza, NEMO

Thus no need to elaborate more about them here.

The ‘pilot’ projects ANTARES, NEMO, NESTOR

Site features :

Multiple depths at relatively close distances from the shore.

The deepest point in the Mediterranean

A different approach from Antares – based on towers than strings – so as to minimize undersea connections

Plan to deploy 4 or 5 floors this summer – and in conjunction with four autonomous strings carry out the NuBE proposal (neutrino burst experiment) with the aim of observing neutrino – gamma ray burst coincidences (>2km2 effective area)

300 m

One floor (star) deployed in 2003 at 4000m and measured muon flux. (reported in previous TAUP)

Exploring the path of extrapolating the present experience towards the design of a much larger structure

~4,000m from the surface

~400m

Existing telescopes “times 30” ?

• Too expensive

• Too complicated

(production, maintenance)

• Not scalable

(readout bandwidth, power, ...)

R&D needed:

• Cost effective solutions

reduce price/volume by factor of at least 2

• Stability

goal: maintenance free detector

• Fast installation

time for construction & deployment less than detector life time

• Improved components

Large volume with same number of PMs?

• PM distance:

given by absorption length in

water (~60 m) and PM properties

• Efficiency loss for larger spacing

New

design ?

Exp

an

d it ? N

o !

Repeat as needed ? No !

Smart tubeX-HPD(R&D)

Segmentation of photo cathode of 10” PMT

multi PMTs in one glass sphere Ref. ICRC0489, P. Kooijman

“Flykt” sphere

New technologies are being investigated

New designs for optical modules

New designs for data transmission – communications - controls• Extension of present systems (e.g. ANTARES readout)

• Wire – fiber network 1:1 system

• Fully photonic system

Considerations of local (in the sea) vs. remote (on shore) data acquisition.New designs for structures – deployment issuesCatania meeting taking place now

• Towers vs. strings ? Or both ?

• How much should we fear and avoid a wet mateable connection ? Is an ROV the best option ? What are the risks ?

• Use general purpose telecom cable ships vs. dedicated vessels ?

Delta Vereniki final major contract was awarded 10 days ago – expected functional in 5-6 months

SeaTop? ...for calibration only ?

Three stations at 20 m distances with 16 m2 scintillators each

Calibration: • angular offset • efficiency • angular resolution• absolute position

Simulating various configurations

Cubic,Ring,Hexagonal,Clustered,IceCube-like...Usually with Antares environmental parameters

Estimating the neutrino effective area

Ref. ICRC0865, J. Carr et al Thesis S. Kuch, Erlangen

Configuration 1 (1 km3):127 lines in hexagonal array100m line spacing25 stories, 15 m apart3 Antares (10”) PMTs per story

Configuration 2 (1 km3):225 lines in a cubic grid95m line spacing36 stories, 16.5 m apart21x3”PMTs per story

Antares site parameters

Estimated sensitivity to HESS sources

Ref. ICRC0865, J. Carr et al

Neutrino energies 1TeV – 1 PeVMuon event rates for 5 years of data taking

Estimated diffuse flux limit

Thesis S. Kuch, Erlangen

Configuration 2:225 strings with lowerhalf sphere multiPMTs

No atmospheric muon background taken

into account

No energy reconstruction

applied

Configuration 2:225 lines with lower

half sphere mulitPMTs

Estimated E-2 flux limit

Thesis S. Kuch, Erlangen

No atmospheric muon background taken into account

Perfect muon energy reconstruction

Neutrino energies

1 TeV – 1 PeV

21 x 3” PMTs

Site selection• KM3NeT report input for discussion:

Evaluation of existing water, oceanographic, biological and geological data from candidate sites

Final choice will depend on– Depth– Distance from shore– Bioluminescence rate– Sedimentation– Biofouling– Sea currents– Earth quake profile– Access to on-shore high speed networks– ……

– Socio-political/regional considerations

?

KM3NeT phases

• Design study: 2006-2009– Technical Design Report

• Preparatory phase: 2008-2011 (proposal submitted)– Political convergence (site)– Commitment for construction of funding agencies/ministries– Governance and legal structure– System prototype– Tendering procedures

• Construction phase: 2010-2013– Build 1 km3 detector

• KM3NeT will be a multidisciplinary research infrastructure:

• Data will be publicly available;

• Data will be buffered to respond to GRB alerts etc.

• Deep sea access for marine sciences.

• KM3NeT will be a European project

8 European countries involved in the Design Study;

Substantial funding already now from national agencies.

E.g. the Greek government has committed to 50 M€.

• KM3NeT will be constructed in time to take data concurrently with IceCube.

• KM3NeT will be extendable.

------------------------------------

• KM3NeT is breaking new ground in the creation/management of multinational projects in the EU – ESFRI framework.

The KM3NeT Vision

Backups …

•

Example: SNR RX J1713.73946

(shell type supernova remnant)

H.E.S.S. : E = 200 GeV – 40 TeV

Acceleration

beyond 100 TeV.

Power law energy

spectrum, index ~2.1–2.2.

Spectrum points to hadron

acceleration ν flux ~ γ flux

Typical ν energies: few TeV

ν 's from Galactic Sources