be00ea2be2ba96c8d8bb8edb640c4c74.ppt
- Количество слайдов: 36
Vulcano Workshop 2008: Frontier Objects in Astrophysics and Particle Physics Vulcano, Eolian Islands, Italy, May 25 -31, 2008 Neutrino Astronomy with KM 3 Ne. T The KM 3 Ne. T physics case § What happened so far The KM 3 Ne. T Conceptual Design Report § 30. 05. 2008 § § Uli Katz ECAP / Univ. Erlangen 30. 05. 2008 The Preparatory Phase: Towards implementation U. Katz: KM 3 Ne. T
The Neutrino Telescope World Map ANTARES + NEMO + NESTOR join their efforts to prepare a km 3 -scale neutrino telescope in the Mediterranean KM 3 Ne. T Design Study 30. 05. 2008 U. Katz: KM 3 Ne. T 2
What is KM 3 Ne. T ? § § Future cubic-kilometre scale neutrino telescope in the Mediterranean Sea Exceeds Northernhemisphere telescopes by factor ~50 in sensitivity Exceeds Ice. Cube sensitivity by substantial factor Focus of scientific interest: Neutrino astronomy in the energy range 1 to 100 Te. V 30. 05. 2008 U. Katz: KM 3 Ne. T 3
Particle Propagation in the Universe protons E>1019 e. V (100 Mpc) Cosmic accelerator neutrinos gammas (0. 01 - 1 Mpc) protons E<1019 e. V 1 parsec (pc) = 3. 26 light years (ly) Photons: absorbed on dust and radiation; Protons/nuclei: deviated by magnetic fields, reactions with radiation (CMB) 30. 05. 2008 U. Katz: KM 3 Ne. T 4
The KM 3 Ne. T Field of View 2 p downward sensitivity assumed Located in Mediterranean visibility of given source can be limited to less than 24 h per day 30. 05. 2008 > 25% U. Katz: KM 3 Ne. T > 75% 5
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: KM 3 Ne. T 6
Point Source Sensitivity § § Based on muon detection Why factor ~3 more sensitive than Ice. Cube? § larger photocathode area better direction resolution Study still needs refinements 30. 05. 2008 U. Katz: KM 3 Ne. T 7
n Flux Predictions from Measurements A. Kappes et al. , B. astro-ph 0607286 Vela X (PWN) Note: hadronic nature of Vela X not clear! measured -ray flux (H. E. S. S. ) mean atm. flux (Volkova, 1980, Sov. J. Nucl. Phys. , 31(6), 784) expected neutrino flux – in reach for KM 3 Ne. T § 1 error bands include systematic errors (20% norm. , 10% index & cut-off) 30. 05. 2008 U. Katz: KM 3 Ne. T 8
Another Case: SNR RXJ 1713. 7 -3946 § § Good candidate for hadronic acceleration. Expected signal well related to measured g flux, but depends on energy cutoff. Few events/year over similar background (1 km 3). KM 3 Ne. T sensitivity in the right ballpark! 30. 05. 2008 U. Katz: KM 3 Ne. T 9
Potential Galactic Sources § The accelerators of cosmic rays - § Interaction of cosmic rays with interstellar matter - § Supernova remnants Pulsar wind nebulae Micro-quasars … Possibly strong n 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. ”Te. V gamma only” objects? 30. 05. 2008 U. Katz: KM 3 Ne. T 10
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 Te. V the neutrino telescope field of view is restricted downwards (n 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: KM 3 Ne. T 11
Diffuse Fluxes § Assuming E-2 neutrino energy spectrum § Only muons studied § Energy reconstruction not yet included 30. 05. 2008 U. Katz: KM 3 Ne. T 12
Dark Matter Sensitivity § Scan m. SUGRA parameter space and calculate neutrino flux for each point § Focus on points compatible with WMAP data § Detectability: - Blue: ANTARES - Green: KM 3 Ne. T - Red: None of them 30. 05. 2008 U. Katz: KM 3 Ne. T 13
KM 3 Ne. T: From the Idea to a Concept 11/2002 3/2004 9/2005 2/2006 First consultations of ANTARES, NEMO and NESTOR 9/2006 4/2008 KM 3 Ne. T on ESFRI Roadmap The KM 3 Ne. T Conceptual Design Report Design Study proposal submitted KM 3 Ne. T on ESFRI List of Opportunities Begin of Design Study 30. 05. 2008 U. Katz: KM 3 Ne. T 14
Major Achievements to Date § Science & technology § Politics & funding § Successful prototype deployments by NEMO and NESTOR Installation and operation of ANTARES A large deep-sea neutrino telescope is feasible! Endorsement by ESFRI and Ap. PEC Funding through EU: Design Study, Preparatory Phase Funding through national authorities: pilot projects, commitments for KM 3 Ne. T Towards construction 30. 05. 2008 Strong collaboration Design concepts in CDR U. Katz: KM 3 Ne. T 15
ANTARES: Progress § § String-based detector; Downward-looking photomultipliers (PMs), axis at 45 O to vertical; 2500 m deep. Currently taking data with 10 lines, completion imminent. 14. 5 m 37 days with 5 lines 25 storeys, 348 m 100 m Junction Box ~70 m 30. 05. 2008 U. Katz: KM 3 Ne. T 16
The KM 3 Ne. T Conceptual Design Report § Presented to public at VLVn. T 0 workshop in Toulon, April 2008 § Summarises (a. o. ) - Physics case Generic requirements Pilot projects Site studies available on www. km 3 net. org Technical implementation Development plan Project implementation 30. 05. 2008 U. Katz: KM 3 Ne. T 17
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 with 21 3’’ PMTs Effective area of reference detector This is NOT the final KM 3 Ne. T design! 30. 05. 2008 U. Katz: KM 3 Ne. T 18
Configuration Studies § § § 30. 05. 2008 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 U. Katz: KM 3 Ne. T 19
KM 3 Ne. T Design Goals § § Sensitivity to exceed Ice. Cube by “substantial factor” Core process: nm+N m+X at neutrino energies beyond 100 Ge. V Lifetime > 10 years without major maintenance, construction and deployment < 4 years Some technical specifications: 30. 05. 2008 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 40 K rate U. Katz: KM 3 Ne. T 20
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: KM 3 Ne. T 21
Optical Modules: Standard or Directional § § A standard optical module, as used in ANTARES Typically a 10’’ PMT in a 17’’ glass sphere A segmented anode and a mirror system allow for directional resolution First prototypes produced 30. 05. 2008 U. Katz: KM 3 Ne. T 22
… 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 photoelectron separation better sensitivity to coincidences directionality Prototype arrangements under study 30. 05. 2008 U. Katz: KM 3 Ne. T 23
… or Hybrid Solutions § § Idea: Use high voltage (~20 k. V) 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 Quasar 370 (Baikal) Prototype development in CERN/Photonis/CPPM collaboration 30. 05. 2008 U. Katz: KM 3 Ne. T 24
Photocathode News § Hamamatsu § § 30. 05. 2008 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! U. Katz: KM 3 Ne. T Photonis 25
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: KM 3 Ne. T 26
The Associated Science Installation § § Associated science devices will be installed at various distances around neutrino telescope Issues: § interfaces operation without mutual interference stability of operation and data sharing Synergy effects 30. 05. 2008 U. Katz: KM 3 Ne. T 27
The 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 30. 05. 2008 U. Katz: KM 3 Ne. T 28
Site Characterisation: An Example Important parameter: water transparency Capo Passero Pylos (460 nm) 30. 05. 2008 Also: optical background, sea currents, sedimentation, biofouling, radioactivity, … U. Katz: KM 3 Ne. T 29
The KM 3 Ne. T Preparatory Phase § § “Preparatory Phase”: A new EU/FP 7 funding instrument restricted to ESFRI projects. KM 3 Ne. T 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: - 30. 05. 2008 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 U. Katz: KM 3 Ne. T 30
Timeline Towards Construction Note: “Construction” includes the final prototyping stage 30. 05. 2008 U. Katz: KM 3 Ne. T 31
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 KM 3 Ne. T detector in the Mediterranean Sea will complement Ice. Cube in its field of view and exceed its sensitivity by a substantial factor § We are working towards a start of construction by 2011 30. 05. 2008 U. Katz: KM 3 Ne. T 32
Deep-sea infrastructure § Major components: § NEMO junction box design 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, work ongoing in NEMO connectors: Expensive, reduce number and/or complexity 30. 05. 2008 U. Katz: KM 3 Ne. T 33
A green power concept for KM 3 Ne. T? § Idea: Use wind and/or solar power at KM 3 Ne. T shore installations to produce the required electrical power. § Requires investment of 4 -5 M€. § Can only work if coupled to a larger (public) power network. 30. 05. 2008 U. Katz: KM 3 Ne. T 34
Deployment: On the surface … § § § 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 Delta-Berenike: triangular platform, central well with crane, water jet propulsion 30. 05. 2008 U. Katz: KM 3 Ne. T 35
… and in the Deep Sea § Deep-sea submersibles are likely needed for - § § Commercially available ROVs laying out the deep-sea cable network making connections to detection units possibly maintenance and surveillance Remotely operated vehicles (ROVs) available for a wide range of activities at various depths Use of autonomous undersea vehicles (AUVs) under study 30. 05. 2008 U. Katz: KM 3 Ne. T 36
be00ea2be2ba96c8d8bb8edb640c4c74.ppt