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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
30.05.2008 U. Katz: KM3NeT 3
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
30.05.2008 U. Katz: KM3NeT 4
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
30.05.2008 U. Katz: KM3NeT 5
The KM3NeT Field of View
2 downward sensitivity assumed
Located inMediterranean visibilityof givensource canbe limitedto less than 24h per day
> 75%> 25%
30.05.2008 U. Katz: KM3NeT 6
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, …
30.05.2008 U. Katz: KM3NeT 7
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
30.05.2008 U. Katz: KM3NeT 8
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!
30.05.2008 U. Katz: KM3NeT 9
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!
30.05.2008 U. Katz: KM3NeT 10
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?
30.05.2008 U. Katz: KM3NeT 11
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
30.05.2008 U. Katz: KM3NeT 12
Diffuse Fluxes
Assuming E-2
neutrino energy spectrum
Only muonsstudied
Energy reconstruction not yet included
30.05.2008 U. Katz: KM3NeT 13
Dark Matter Sensitivity
Scan mSUGRAparameter spaceand calculateneutrino flux foreach point
Focus on pointscompatible withWMAP data
Detectability:
- Blue: ANTARES
- Green: KM3NeT
- Red: None of them
30.05.2008 U. Katz: KM3NeT 14
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
30.05.2008 U. Katz: KM3NeT 15
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
30.05.2008 U. Katz: KM3NeT 16
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
30.05.2008 U. Katz: KM3NeT 17
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
30.05.2008 U. Katz: KM3NeT 18
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
30.05.2008 U. Katz: KM3NeT 19
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
30.05.2008 U. Katz: KM3NeT 20
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
30.05.2008 U. Katz: KM3NeT 21
Technical Implementation
Photo-sensors and optical modules
Data acquisition, information technology and electronics
Mechanical structures
Deep-sea infrastructure
Deployment
Calibration
Associated science infrastructure
30.05.2008 U. Katz: KM3NeT 22
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
30.05.2008 U. Katz: KM3NeT 23
… 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
30.05.2008 U. Katz: KM3NeT 24
… 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)
30.05.2008 U. Katz: KM3NeT 25
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
30.05.2008 U. Katz: KM3NeT 26
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
30.05.2008 U. Katz: KM3NeT 27
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
30.05.2008 U. Katz: KM3NeT 28
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
30.05.2008 U. Katz: KM3NeT 29
Site Characterisation: An Example
Important parameter:water transparency
Pylos(460 nm)
Capo Passero
Also: optical background,sea currents, sedimentation,
biofouling, radioactivity, …
30.05.2008 U. Katz: KM3NeT 30
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
30.05.2008 U. Katz: KM3NeT 31
Timeline Towards Construction
Note: “Construction” includes the final prototyping stage
30.05.2008 U. Katz: KM3NeT 32
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
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