a. belias, nestor institute, pylos, greece tevpa 2009, july 13-17, slac1 km3net, a deep sea neutrino...
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A. BELIAS, NESTOR Institute, Pylos, Greece
TeVPA 2009, July 13-17, SLAC 1
KM3NeT, a deep sea neutrino telescope in the Mediterranean Sea
KM3NeT objectives
The KM3NeT Design Study
Outlook
Anastasios Belias for the KM3NeT Consortium
A. BELIAS, NESTOR Institute, Pylos, Greece
TeVPA 2009, July 13-17, SLAC 2
A -telescope in the Mediterranean sea
Complementarity with Ice Cube coverage
We need Northern -telescope to cover the Galactic Plane
A. BELIAS, NESTOR Institute, Pylos, Greece
TeVPA 2009, July 13-17, SLAC 3
The KM3NeT Consortium
• Consists of 40 Institutes of 10 European States• Includes expertise from all three precursor projects,
ANTARES, NEMO, NESTOR• Objectives
– Build and operate an extensible km3-scale water Cherenkov neutrino telescope in the Mediterranean Sea
– Sustain a deep-sea research infrastructure for earth and marine sciences
• KM3NeT, a multidisciplinary research infrastructure– Synergetic with European Multidisciplinary Seafloor Observatory
(EMSO)
A. BELIAS, NESTOR Institute, Pylos, Greece
TeVPA 2009, July 13-17, SLAC 4
KM3NeT Objectives• 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• The unexpected
• Earth and marine sciences– Long-term, continuous measurements in deep-sea– Marine biology, oceanography, geology/geophysics, …
A. BELIAS, NESTOR Institute, Pylos, Greece
TeVPA 2009, July 13-17, SLAC 5
The KM3NeT Design Study• Supported by the European Union in FP6 with ~9M€,
tot. value ~20M€.• Timeline:
• Started on Feb. 1, 2006 and will end on Oct. 31, 2009• Conceptual Design Report published, April 2008• Technical Design Report by end of 2009
• Detector Target Specifications:• Effective volume ≥ 1km3 • 0.1o angular resolution for muons (E ≥ 10TeV)• Energy threshold few 100 GeV• Field of view close to 4π for high energies
A. BELIAS, NESTOR Institute, Pylos, Greece
TeVPA 2009, July 13-17, SLAC 6
Deep-sea -Telescope at work• Upward-going neutrinos
interact in rock or sea water.
• Emerging charged particles (in particular muons) produce Cherenkov light in water.
• Detection by array of photomultipliers.
• Focus of scientific interest: Neutrino astronomy in the energy range 1 to 100 TeV.
A. BELIAS, NESTOR Institute, Pylos, Greece
TeVPA 2009, July 13-17, SLAC 7
• A standard optical module, as used in ANTARES, NEMO, NESTOR
• Typically a single largediameter (10’’) PMT
in a 17’’ glass sphere
Optical Module: standard...
A. BELIAS, NESTOR Institute, Pylos, Greece
TeVPA 2009, July 13-17, SLAC 8
… or many small PMTs
• Use up to 31 small (3’’) PMTs in a standard 17’’ glass sphere– very high QE PMTs
• Advantages: – increased photocathode
area– significant improved TTS– directionality– improved 1-vs-2 photo-
electron separation better sensitivity to coincidences
• Prototype tests underway
A. BELIAS, NESTOR Institute, Pylos, Greece
TeVPA 2009, July 13-17, SLAC 9
Electronics & Data Readout Concepts• Front-end options studies• New improved front-end chip in the deep-sea
– New FPGA/CPU
• Minimize active electronics in deep-sea– Reflective optical
modulator – on-shore timestamp
• Both options use fibers, Wavelength Division Multiplexing and Point-to-point networks
• “ALL DATA TO SHORE”
Interlink cables
SubmarineTelecom cable
A. BELIAS, NESTOR Institute, Pylos, Greece
TeVPA 2009, July 13-17, SLAC 10
Shore station real-time processing
• ALL digitized PMT data are sent to shore
• Expected rate of ~ 100Gb/s cannot be stored
• Perform time - position correlations of photomultiplier hits
• Correlations in real-time for the whole telescope
• Data reduction factor: ~10000
A. BELIAS, NESTOR Institute, Pylos, Greece
TeVPA 2009, July 13-17, SLAC 11
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
A. BELIAS, NESTOR Institute, Pylos, Greece
TeVPA 2009, July 13-17, SLAC 12
Mechanical structures
- Flexible tower structure:
Tower deployed in compactified “package” and unfurls thereafter
- String structure:
Compactified string at deployment, unfolding on sea bed
A. BELIAS, NESTOR Institute, Pylos, Greece
TeVPA 2009, July 13-17, SLAC 13
Deployment & Sea Operations• Deployment with ships
or dedicated platforms.• Ships:
Buy, charter or use
ships of opportunity.• Platform:
Delta-Berenike, under construction in Greece• Deep-sea submersibles
– Remotely operated vehicles (ROVs)– Autonomous Undersea Vehicles (AUVs) under study
Delta-Berenike: triangularplatform, central well with crane,
water jet propulsion
All deployment options require ships or platforms with GPS and DP
A. BELIAS, NESTOR Institute, Pylos, Greece
TeVPA 2009, July 13-17, SLAC 14
Earth and Marine Sciences• Associated science
devices will be installed at variousdistances aroundneutrino telescope
• Issues addressed:– operation without
mutual interference– interfaces– stability of operation
and data sharing
A. BELIAS, NESTOR Institute, Pylos, Greece
TeVPA 2009, July 13-17, SLAC 15
The candidate sites• Important Criteria• Bioluminescence rate• Biofouling• Sedimentation• Sea Currents• Absorption length• Depth• Distance from Shore• Access to shore facilities• Long-term site
measurementsperformed and ongoing
• Site decision requiresscientific, technologicaland political input
A. BELIAS, NESTOR Institute, Pylos, Greece
TeVPA 2009, July 13-17, SLAC 16
NESTOR 4.5 D Site36O 31.336’ N / 21O 25.635’ E
Site characterisation: Example
Transmission lengthvs
wavelength
A. BELIAS, NESTOR Institute, Pylos, Greece
TeVPA 2009, July 13-17, SLAC 17
KM3NeT Roadmap • Design study Feb. 1, 2006 – Oct. 31, 2009
– Produced Conceptual Design Report– Will produce Technical Design Report (by end. 2009)
• “Preparatory Phase” EU funded ~5M€, tot. ~10M€ 3/2008 – 2/2011– Initiate political process towards convergence and legal
structure– Prepare operation organisation & user communities– System prototypes– Commitment of funding agencies
• Site selection around 2010 ?• Construction Phase 2011+
– Start on extendable km3–scale neutrino telescope
A. BELIAS, NESTOR Institute, Pylos, Greece
TeVPA 2009, July 13-17, SLAC 18
KM3NeT Technical Design Report will address key issues
• Maximize physics output for given budget:• Which architecture and structure to use?
– String vs Tower concept• How to get the data to shore?
– Electronics off-shore or on-shore• How to calibrate the detector?
– Separate calibration and detection units• Design of photo-detection units?
– Large vs several small PMTs• Deployment technology?
– Dry vs wet ROV/AUV vs hybrid
A. BELIAS, NESTOR Institute, Pylos, Greece
TeVPA 2009, July 13-17, SLAC 19
Outlook• Joint efforts of ANTARES, NEMO, NESTOR to build a
km3-scale neutrino telescope in the Mediterranean Sea
• The Technical Design Report will be ready by end 2009
• The Preparatory Phase started
• Towards construction to start in 2011+
• The km3-scale neutrino telescope in the Mediterranean Sea will complement IceCube in its field of view
A. BELIAS, NESTOR Institute, Pylos, Greece
TeVPA 2009, July 13-17, SLAC 20
A. BELIAS, NESTOR Institute, Pylos, Greece
TeVPA 2009, July 13-17, SLAC 21
Backup slides
A. BELIAS, NESTOR Institute, Pylos, Greece
TeVPA 2009, July 13-17, SLAC 22
Simulations of 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
A. BELIAS, NESTOR Institute, Pylos, Greece
TeVPA 2009, July 13-17, SLAC 23
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
A. BELIAS, NESTOR Institute, Pylos, Greece
TeVPA 2009, July 13-17, SLAC 24
Diffuse fluxes
• Assuming E-2
neutrino energy spectrum
• Only muonsstudied
• Energy reconstruction not yet included
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