km3net - a next generation neutrino telescope in the mediterranean sea
DESCRIPTION
KM3NeT - a next generation neutrino telescope in the Mediterranean Sea. For the KM3NeT Collaboration Petros A. Rapidis National Center for Scientific Research “Demokritos”, Athens, Greece and NESTOR Experiment Collaboration. - PowerPoint PPT PresentationTRANSCRIPT
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