Transcript Slide 1

A next generation neutrino
telescope
Els de Wolf
Nikhef/University of Amsterdam
on behalf of the KM3NeT consortium
TeVPA 2008, 27 September 2008
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Acronym for KM3Neutrino Telescope
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A research facility in the Mediterranean Sea
 Cubic kilometre size neutrino telescope
 Cabled observatory for Earth and Marine sciences
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38 institutes from:
Cyprus, France, Germany, Greece, Ireland
Italy, Netherlands, Romania, Spain, UK
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2π downward sensitivity assumed
Visibility Galactic Centre 66%
> 25%
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> 75%
Angular resolution for E>10 TeV: ~0.1o
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NOW
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Made public April 2008 at
VLVnT workshop in Toulon
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Being printed
(already at www.km3net.org)
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Includes (a.o.):
Science case
Site studies
Design goals
Technical implementation
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Neutrino astroparticle physics
 Galactic and Extragalactic point sources
 Diffuse neutrino flux
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Dark Matter and exotics
 Neutrinos from Dark Matter annihilation
 Magnetic monopoles, nuclearites, strangelets, …
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Neutrino and particle physics (~105 νatm/year)
 UHE neutrino cross sections
 Muons (≥ 108 μatm/year)
 Prompt muons from heavy meson decay
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Earth and marine sciences
 Long-term, continuous measurements in deep-sea
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Geometry (~1 km3):
 15 x 15 vertical detection units
on rectangular grid
 1 OM per storey
 21 PMTs (3”) per OM
Effective Area
 Horizontal OM-distance 95 m
 Vertical OM-distance 15.5 m
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Thesis S. Kuch, Erlangen
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Muon energy
reconstruction
perfect
Neutrino energies
1 TeV – 1 PeV
~50 times better
than ANTARES
~3 times better
than IceCube:
 Larger
photocathode area
 Better angular
resolution
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Assuming E-2
neutrino energy
spectrum
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No energy
reconstruction
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Candidate for hadronic
acceleration
 Source extension
Φ ~ 1.3°
 ~75% of the time below
the horizon
→ in 5 years: 5 neutrinos
over 15 background events
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Kappes et al, astro-ph/0607286
Dornic et al, astro-ph/0711.2145
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0.5 events
± 1 order of magnitude
uncertainty, very large
model uncertainty
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Contribution GRBs to
diffuse flux: few 10
neutrinos per year
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Slow jet model of core
collapse SN seems
promising for neutrino
detection
Predicted neutrino spectrum
Dornic et al, NIM Physics A
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Neutrino flux from Cen A (~4 Mpc)
 Assuming 2 CR detected in a window of 3.2 degrees
 Few to several 10-3 neutrinos per year (very model
dependent)
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Scan mSUGRA parameter space
Focus on points
compatible with
WMAP data
Detectability:
 Blue: ANTARES
 Green: KM3NeT
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Longterm, continous
measurements will open new
applications
KM3NeT will be a node in
network for monitoring
European coasts
Sampling rates of order kHz
i.s.o. 1/min or 1/hour
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A few examples
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Density of
bioluminescence
sources as function
of depth estimated
from measurements
Deeper -> less BL
Black: east Med. Sea.
Grey: west Med. Sea.
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Using 460 nm light source
Normalised to 2850 m depth
Capo Passero
Sicily, Italy
Pylos
Greece
Also: sea currents, sedimentation, biofouling, radioactivity,…
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Use solar or wind
energy at shore
station
4.4 GWh/year
during operation
Requires
investment of
Wind map
4-5 M€
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Only feasible if
coupled to larger
power network
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Substantially better sensitivity than IceCube
> 1 km3
Core process:
nm+N  m+X at neutrino energies beyond 100 GeV
Construction and deployment < 4 years
Data taking period > 10 year
Optimised for energy range 1 TeV – 1 PeV
Angular resolution < 0.1o
Zenith angle:
 Full acceptance for neutrinos originating from directions up to at least
10° above the horizon
 For energies > 100 TeV angular acceptance limited only by the
absorption of the Earth
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A few examples
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With horizontal
structures
> 2 OMs per storey
1 large(10”) PMT per
OM
Copper/fiber readout
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No horizontal
structures
1 OM per storey
31 small (3”) PMTs per
OM
Fiber readout
Cost and reliability studied
Further constraint towards final decision for TDR
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1 x 10” PMT
31 x 3” PMTs
17”glass container
Improved Antares OM
with electronics inside
Possibly with 13” glass
container
17” glass container
High 2 photon purity (sea background)
Looking ~upwards (atm. muons)
Large photocathode area
17” glass container
4 anodes + mirrors
Direction sensitive
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Further simulations required
Costs and reliability studied
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Hybrid solution: scintillator+small PMT
Send photo electrons on scintillator
Detect scintillator light with small PMT
 Very good photo-electron counting
 Large angular sensitivity
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CERN/Photonis/CPPM
development
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Quasar 370
(Baikal)
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Using ships (lease or buy)
or the Delta Berenike platform
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Junction boxes
(self made or buy)
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Remotely
operated vehicle
(lease or buy)
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Autonomous
Undersea vehicle
(buy)
Also: power network and data network (redundancy)
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Wire/Fiber mix
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Copper in vertical cable
Special ASIC off-shore
Fiber only
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Possibly local coincidences
off-shore
Time-stamp off-shore
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Fibers in vertical cable
Continuous sampling of TDC
signal
Minimal electronics off-shore
Local coincidences on-shore
Time stamp on-shore or offshore
Cost and reliability studied
Further constraint towards final decision for TDR
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New EU/FP7 funding instrument restricted to
projects on the ESFRI roadmap
KM3NeT proposal endorsed with 5 M€
3-year project 2008-2011
Objectives:
 Definition of legal structure & governance
 Political convergence: site issue & funding
 Strategic issues: new partners, extendibility detector,
multiple sites,…
 Operational phase: organisation & user communities
 Pre-procurement with industrial partners
 System prototyping
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Science case of KM3NeT shown:
 Neutrino (astro)particle physics
 Marine and Earth sciences
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Conceptual Design Report KM3NeT published
Technical Design Report foreseen in October 2009
Working towards start of construction in 2011
KM3NeT will be a new generation facility:
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Point source sensitivity ~50 times that of ANTARES
Point source sensitivity ~3 times that of IceCube
Complementary with IceCube in field of view
New opportunities for marine and earth sciences
KM3NeT considers the concept of green energy
New groups are more than welcome!
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Thank you!
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• In Mediterranean Sea
• All suitable with pros
and cons:
• ANTARES, France
• NEMO, Sicily
• NESTOR, Greece
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Decision requires
scientific, technological
and political input
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None optimal for ALL energies and directions
Deployment and subsea-infrastructure also plays a
role in decision
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Devices installed around telescope
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Issues
 Interfaces
 Interference
during data
taking
Synergy effects:
 Sharing
environmental
data
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Hamamatsu
~43%
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Photonis
~55%
2 x higher Q.E. -> 2 x larger photocathode area
Major gain in sensitivity
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Height ab.
bottom
(m)
E.g.studies of
 Large-scale ocean circulation
 Specific processes, e.g. internal waves
 Effects on sediment and nutrients redistribution
Temperature [12.3, 14.1]C
 Bio-acoustics
 …
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H. vanHaren, NIOZ
yearday
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