Transcript Status of the Antares underwater neutrino telescope

KM3NeT: a deep-sea
neutrino telescope in the
Mediterranean Sea
Paolo Piattelli - INFN/LNS Catania (Italy)
on behalf of the KM3NeT Consortium
Paolo Piattelli - KM3NeT
IAPS - Golden, 6-8 may 2008
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 costeffective 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
Paolo Piattelli - KM3NeT
IAPS - Golden, 6-8 may 2008
Timeline towards construction
Paolo Piattelli - KM3NeT
IAPS - Golden, 6-8 may 2008
KM3NeT Conceptual Design Report
Describes the
scientific objectives, and the
concepts behind the design,
construction, and operation of the
KM3NeT Research Infrastructure
Will soon be available on the
KM3NeT consortium web site
http://www.km3net.org
Paolo Piattelli - KM3NeT
IAPS - Golden, 6-8 may 2008
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, …
Paolo Piattelli - KM3NeT
IAPS - Golden, 6-8 may 2008
Why in the Mediterranean Sea?
Observed sky region in
galactic coordinates
assuming efficiency for
downward
hemisphere.
> 75% Visibility
> 25% Visibility
Paolo Piattelli - KM3NeT
IAPS - Golden, 6-8 may 2008
Design goals
• Sensitivity to exceed IceCube by “substantial factor”
• Core process:
nm+N  m+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
Paolo Piattelli - KM3NeT
IAPS - Golden, 6-8 may 2008
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 with
Effective area
21 3’’ PMTs
of reference
detector
NOT the final
KM3NeT design!
Paolo Piattelli - KM3NeT
IAPS - Golden, 6-8 may 2008
Point source sensitivity
• Based on muon
detection
• Factor ~3 more
sensitive than
IceCube
– larger photocathode area
– better direction
resolution
• Study still needs
refinements
Paolo Piattelli - KM3NeT
IAPS - Golden, 6-8 may 2008
Diffuse fluxes
• Assuming E-2
neutrino energy
spectrum
• Only muons
studied
• Energy
reconstruction
not yet included
Paolo Piattelli - KM3NeT
IAPS - Golden, 6-8 may 2008
Configuration studies
• Various geometries and OM configurations have
been studied
• None is optimal for all energies and directions
• Local coincidence requirement poses important
constraints
Paolo Piattelli - KM3NeT
IAPS - Golden, 6-8 may 2008
KM3NeT CDR contents
1.
2.
3.
4.
5.
6.
7.
8.
9.
Introduction
Science case
The KM3NeT concept
Neutrino telescope
design goals
Pilot projects
Site investigations
Technical
implementation
Development plan
Project implementation
Paolo Piattelli - KM3NeT
7.1.
7.2.
7.3.
7.4.
Optical modules
Information technology
Mechanics
Deep-sea and shore
infrastructures
7.5. Deployment
7.6. Calibration
IAPS - Golden, 6-8 may 2008
Optical Modules
Standard or directional …
Segmentation of photo cathode of 10” PMT
Paolo Piattelli - KM3NeT
IAPS - Golden, 6-8 may 2008
Optical Modules
… 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
Paolo Piattelli - KM3NeT
IAPS - Golden, 6-8 may 2008
Optical Modules
… 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
Paolo Piattelli - KM3NeT
Quasar 370
(Baikal)
IAPS - Golden, 6-8 may 2008
Mechanical structures
Four options considered
Tower like
String like
- Extended tower structure: NESTOR
like, arm length up to 60 m
- String structure: Compactified at
deployment, unfolding on sea bed
- Flexible tower structure: NEMO like,
tower deployed in compactified
“package” and unfurls thereafter
- Cable based concept: one (large) OM per
storey, separate mechanical and electrooptical function of cable, compactified
deployment
Paolo Piattelli - KM3NeT
IAPS - Golden, 6-8 may 2008
Deep-sea infrastructure
• Major components:
– main cable & power
transmission
– network of secondary cables
with junction boxes
– connectors
• Design considerations:
– cable selection likely to be
driven by commercial availability
– junction boxes: may be
custom-designed
– connectors: Expensive, reduce
number and/or complexity
Paolo Piattelli - KM3NeT
NEMO junction box design
Technology with double vessel system
IAPS - Golden, 6-8 may 2008
Deployment
• Deployment operations
require ships or dedicated
platforms
Ships: Buy, charter or use
ships of opportunity
Platform: Delta-Berenike,
under construction in Greece,
ready summer 08
Paolo Piattelli - KM3NeT
IAPS - Golden, 6-8 may 2008
Associated sciences
• The KM3NeT
infrastructure will serve
as a platform for deepsea and earth sciences
• Strong synergy with
the deep-sea science
community
• Associated science
devices will be
installed at various
distances around
neutrino telescope
 KM3NeT site in
 ESONET (European Sea-floor Observatory NETwork)
 EMSO (European Multi-disciplinary Sea-floor Observatory research
infrastructure)
Paolo Piattelli - KM3NeT
IAPS - Golden, 6-8 may 2008
Candidate sites
• Locations of the
three pilot projects:
– ANTARES: Toulon
– NEMO: Capo Passero
– NESTOR: Pylos
• All appear to be
suitable
• Long-term site
characterisation
measurements
performed and ongoing
• Site decision requires
scientific, technological
and political input.
Paolo Piattelli - KM3NeT
IAPS - Golden, 6-8 may 2008
Summary and conclusions
Paolo Piattelli - KM3NeT
IAPS - Golden, 6-8 may 2008