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Hunting for Cosmic Neutrinos in the Deep Sea — The ANTARES Neutrino-Telescope

Hunting for Cosmic Neutrinos in the Deep Sea — The ANTARES Neutrino-Telescope. Alexander Kappes Physics Institute Univ. Erlangen-Nuremberg. October 11, 2005 Univ. Wisconsin, Madison. Introduction The ANTARES Neutrino Telescope Results from MILOM and Line0 The Future: KM3NeT.

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Hunting for Cosmic Neutrinos in the Deep Sea — The ANTARES Neutrino-Telescope

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  1. Hunting for Cosmic Neutrinos in the Deep Sea—The ANTARES Neutrino-Telescope Alexander Kappes Physics Institute Univ. Erlangen-Nuremberg October 11, 2005Univ. Wisconsin, Madison • Introduction • The ANTARES Neutrino Telescope • Results from MILOM and Line0 • The Future: KM3NeT

  2. satellites/balloons shower detectors Cosmic Radiation • Discovered in 1912 byVictor Hess during a balloon flight • At high energies predominantlyconsists of:protons and a particles What are the sources and acceleration mechanisms? October 11, 2005 Univ. Wisconsin, Madison

  3. ne: nm: nt≈ 1 : 2 : 0N (n) ≈ N (n) Messengers from Deep Space Magnetic fields • Neutrino production: Reaction of accelerated protons with interstellar medium, 3K microwave background radiation or synchrotron radiationp + p(g)→p + X9m+nm9 e + ne+nm)observation of  prove for hadron acceleration • Neutrino oscillation results in ne : nm : nt≈ 1 : 1 : 1 Protons E<1019 eV Gammas (R~150 Mpc @ E=10 TeV) produced in electron or hadron acceleration Neutrinos CosmicAccelerator Protons E>1019 eV (R~50 Mpc) October 11, 2005 Univ. Wisconsin, Madison

  4. Detection of Cosmic Neutrinos Čerenkov light: Čerenkov angle: 42o wave lengths used: 350 – 500 nm Earth used as shield against all other particles  A! X low  cross section requires large detector volumes key reaction: + N! + X n  Detector deployed in deep water / ice to reduce downgoing atmospheric muons p October 11, 2005 Univ. Wisconsin, Madison

  5. Dark Matter (WIMPs): direction, energy Cosmic point Sources: direction, (energy) Diffuse neutrino flux: energy, (direction) E GeV TeV PeV EeV Physics with Neutrino Telescopes • High energy limit: • flux decreases withE-2 … E-3 • Large volumes required • Low energy limit: • short  tracks) only few photo sensors give signal • in sea water:40K + bioluminescence give high background can only be lowered with a denser instrumentation of the water/ice . . . and also: - GZK neutrinos - supernova detection - magnetic monopoles - . . . October 11, 2005 Univ. Wisconsin, Madison

  6. Current and Future Neutrino Telescopes ANTARES Medium: sea water; under construction BAIKAL Medium: fresh water; Data since 1991 NESTOR Medium: sea water; under construction AMANDA IceCube Medium: ice Data since 1997 under construction R&D project for km3 detector: NEMO (Mediterranean) Future project (km3): KM3NeT (Mediterranean) October 11, 2005 Univ. Wisconsin, Madison

  7. Mkn 421 Mkn 501 Mkn 501 not visible Crab Crab VELA SS433 SS433 not visible Galactic Centre RX J1713 Why a telescope in the Mediterranean? • Sky coverage complementary to AMANDA/IceCube • Allows observation of the Galactic Centre South Pole Mediterranean Galactic Centre Sources of VHE  emissions (HESS 2005) October 11, 2005 Univ. Wisconsin, Madison

  8. Neutrinos from H.E.S.S. Sources? Example: SNR RX J1713.7(shell-type supernova remnant) • Acceleration beyond 100 TeV. • Power law energy spectrum, index ~2.1–2.2. • Multi-wavelength spectrum points to hadron acceleration) neutrino flux ~ g flux • Detectable in current and/or future neutrino telescopes?! W. Hofmann, ICRC 2005 October 11, 2005 Univ. Wisconsin, Madison

  9. The ANTARES Collaboration 20 Institutes from6 European countries October 11, 2005 Univ. Wisconsin, Madison

  10. Buoy 460 m String Cable to Shore station Optical Module 14.5 m Junction Box Submersible 70 m The ANTARES Detector • Hostile environment: • pressure up to 240 bar • sea water (corrosion) artist´s view (not to scale) October 11, 2005 Univ. Wisconsin, Madison

  11. One of 12 ANTARES Strings • Buoy • keeps string vertical (horizontal displacement < 20 m) • Storey • 3 optical modules (45o downwards) • electronics in titanium cylinder • EMC cable • copper wires + glass fibres • mechanical connection between storeys • Anchor • connector for cable to junction box • control electronics for string • dead weight • acoustic release mechanism October 11, 2005 Univ. Wisconsin, Madison

  12. optical module B-screening An ANTARES Optical Module • Glass spheres: • material: borosilicate glass (free of 40K) • diameter: 43 cm; 1.5 cm thick • qualified for pressures up to 650 bar • Photomultipliers (PMT): • Ø 10 inch (Hamamatsu) • transfer time spread (TTS) = 1.3 ns • quantum efficiency: > 20% @ 1760 V (360 <  < 460 nm) October 11, 2005 Univ. Wisconsin, Madison

  13. Calibration systems • Time calibration with pulsed light sources • required precision: 0.5 ns (1ns = 20 cm) • 1 LED in each optical module • Optical emitter- LED beacon at 4 different storeys- Laser at anchor • Acoustic positioning system • required precision: < 10 cm • receiver (Hydrophone) at 5 storeys • 1 transceiver at anchor • autonomous transceiver on sea bottom • Tiltmeter and compass at each storey October 11, 2005 Univ. Wisconsin, Madison

  14. Control room DAQ and Online Trigger • Data acquisition: • signals digitized in situ(either wave-form or integrated charge (SPE)) • all data above low threshold (~0.3 SPE)sent to shore • no hardware trigger • Online trigger: • computer farm at shore station (up to 100 PCs) • data rate from detector ~1GB/s(dominated by background) • trigger criteria: hit amplitudes, local coincidences, causality of hits • trigger output ~1MB/s = 30 TB/year Computer Centre October 11, 2005 Univ. Wisconsin, Madison

  15. cos C = 1 / n Online Trigger • Each PMT sends frame with hits of last 13 ms to shore • all 1800 concurrent frames (2 per PMT) are combined to 1 timeslicewhich is analysed by the online trigger on one PC: Trigger logic: • Level 1: coincidences at one storey (Dt < 20 ns) or large individual signal (& 2.4 SPE) • Level 2:causality condition Dt < n / c· Dx • Level 3: accept if sufficiently many causally related hits exist Choice of trigger parameters: discard background events to match allowed trigger output rate (~1 MB/s) October 11, 2005 Univ. Wisconsin, Madison

  16. Efficiency Bckg rate Online Trigger Important performance criteria: • CPU time per event • Scaling of trigger rate with increasing background rate • Efficiency for E < 1 TeV ) Dark Matter (WIMP) search • Increased sensitivity for certain directions (directional trigger)) WIMP & point sources First studies:Efficiency 100 GeV < E < 1 TeV increases by factor ~2 using directional triggerbut a lot of CPU power required )further investigations necessary October 11, 2005 Univ. Wisconsin, Madison

  17. Muons E > 10 GeV Background (100 kHz) Optimising the Online Trigger • causality relation:Dt < n / c· Dx • Dxmin = minimum of distances of all hit pairs in an accepted event • Cut @ Dxmin < 60 m: Background suppression ≈ 97%, Efficiency loss ≈ 1.5% October 11, 2005 Univ. Wisconsin, Madison

  18. muon track hadronic shower electromagn. shower hadronic shower hadronic shower Signatures of Neutrino Reactions Two basic light sources: • Čerenkov photons from muon • track-like source • Čerenkov photons from shower • hadronic or electromagnetic • “point-like” source visible in detector in all combinations October 11, 2005 Univ. Wisconsin, Madison

  19. position resolution (Preliminary) Shower Reconstruction with ANTARES(PhD thesis B. Hartmann) Position reconstruction: • use timing and position information (xi ,yi ,zi ,ti) of N hits • distance dibetween assumed shower position (x,y,z,t) and OMi: • subtract di in pairs ) N-1 linear equations • solve system of linear equations algebraically ) # hits ¸ 5 (on at least 3 lines) Results (no cuts): • Position resolution: ~1 m • shift due to elongation of shower October 11, 2005 Univ. Wisconsin, Madison

  20. (Preliminary) (E > 100 TeV; 60 kHz bckgr per PMT,) (Preliminary) 60 kHz bckgr per PMT # photons PMT opening angle PMT angularefficiency parameterisationof c distribution absorption Shower Reconstruction with ANTARES Direction and energy reconstruction: • prefit for direction and energy • final parameters (, , E) ) Log-Likelihood fitNi = # photons in PMT i Results (no cuts): • Event sample: Instrumented volume + 1 absorption length • Angular resolution: < 13o (E > 10 TeV) • but large tails in distributions • Energy resolution:log(E) ¼ 0.1 October 11, 2005 Univ. Wisconsin, Madison

  21. 60 kHz bckgr per PMT (Preliminary) Shower Reconstruction with ANTARES Likelihood in - plane New idea for minimization strategy: (Diploma thesis R. Auer) • common to all events: each minimum lies in broad valley • impose grid on parameter plane (, , E) and calculate likelihood for centre of tiles • take l tiles with best likelihood values and divide those into sub-tiles) compare L of sub-tiles within one tile • stop after k iterations ( k¼ 7) and take tile with best likelihood  f Results (no cuts): • Event sample: fully contained events; 30 TeV < E < 50 TeV • L function: similar to previous one • angular resolution: ~2.4o • no tails in distribution October 11, 2005 Univ. Wisconsin, Madison

  22. New Test-Lines: MILOM and Line0 Deployed March 2005, connected April 2005 Line0: full line without electronics (test of mechanical structure) MILOM:Mini Instrumentation Line with Optical Modules October 11, 2005 Univ. Wisconsin, Madison

  23. MILOM setup Optical components: • equipped with final electronics • 3+1 optical modules at two storeys • timing calibration system: • two LED beacons at two storeys • Laser Beacon attached to anchor • acoustic positioning system: • receiver at 1 storey • transceiver (transmitter + receiver) at anchor allows to test all aspects of optical line Instrumentation components: • current profiler (ADCP) • sound velocimeter • water properties (CSTAR, CT) October 11, 2005 Univ. Wisconsin, Madison

  24. 0 40 80 120 Time (ADC channel) First results from MILOM (selection) Single photon resolution (threshold 4 mV ¼ 0.1 SPE) pulse shape PMT charge spectrum amplitude (a.u.) single photon peak time (a.u.) October 11, 2005 Univ. Wisconsin, Madison

  25. First results from MILOM (selection) Time calibration with LED beacons: • Determination of the relative time offset of 3 optical modules at same storey • Usage of large light pulses ) TTS of PMTs small Time difference between optical modules =0.75ns =0.68ns t OM1 – OM0 t OM2 – OM0 • Contribution of electronics to time resolution ca. 0.5 ns October 11, 2005 Univ. Wisconsin, Madison

  26. First results from MILOM MILOM is a success: • Data readout (waveforms + SPE) is working as expectedand yields ns timing precision • In situ timing calibration reaches required precision for target angular resolution (< 0.3o für E& 10 TeV) • All environmental sensors are working well • Continuous data from Slow Control (monitoring of various detector components) • Lots of environmental and PMT data are available andare currently analysed October 11, 2005 Univ. Wisconsin, Madison

  27. Line0 • deployed to test mechanical structure • equipped with autonomous recording devices • water-leakage sensors • sensors to measure attenuation in electrical and optical fibres • recovered in May 2005 Results: • no water leaks • optical transmission losses at entry/exit of cables into/out of electronics containers • Effect caused by static water pressure;Reason understood and reproduced in pressure tests • Solutions available; detector installation not significantly delayed October 11, 2005 Univ. Wisconsin, Madison

  28. ANTARES: further schedule • Assembly of first complete string (Line 1) started last week • Deployment and connection ca. January 2006 • Completion of the full detector until 2007 • From 2006 on: physics data! October 11, 2005 Univ. Wisconsin, Madison

  29. The future: km3 detectors in the Mediterranean HENAP Report to PaNAGIC, July 2002: • “The observation of cosmic neutrinos above 100 GeV is of great scientific importance. ...“ • “... a km3-scale detector in the Northern hemisphere should be built to complement the IceCube detector being constructed at the South Pole.” • “The detector should be of km3-scale, the construction of which is considered technically feasible.” October 11, 2005 Univ. Wisconsin, Madison

  30. Towards a km3 scale detector • Existing telescopes “times 50“: • to expensive • to complicated: production/installation takes forever,maintenance impossible • not scalable (band width, power supply, ...) scale up new design thin out • R&D required: • cost effective solutions: reduction price/volume by factor & 2 • StabilityAim: maintenance free detector • fast installationtime for assembly & deployment shorter than lifetime of detector • improved components • Large volume with same number of PMTs: • PMT distance: given by absorption length in water (~60 m) and PMT characteristics) efficiency losses for larger distances October 11, 2005 Univ. Wisconsin, Madison

  31. The future: KM3NeT EU FP6: Design-Studie for a “Deep-Sea Facility in the Mediterranean for Neutrino Astronomy and Associated Sciences” • Start of the initiative Sept. 2002; intensive discussions andcoordination meetings since beginning of 2003 • VLVnT Workshop, Amsterdam, Oct. 2003! second workshop 8.-11. Nov. 2005 in Catania • ApPEC review, Nov 2003. • Proposal submission to EU 4. March 2004 • EU offer about 9 M€, July 2005 (total budget ~20 M€); • Start of the Design Study beginning of 2006;Goal: Technical Design Report after 36 months • Start of construction shortly afterwards October 11, 2005 Univ. Wisconsin, Madison

  32. The future: KM3NeT Partners in the Design Study:(contains ANTARES, NEMO, NESTOR projects) • Germany: Univ. Erlangen, Univ. Kiel • France: CEA/Saclay, CNRS/IN2P3 (CPP Marseille, IreS Strasbourg, APC Paris),UHA Mulhouse, IFREMER • Italy: CNR/ISMAR, INFN(Univ. Bari, Bologna, LNS Catania, Genova, Naples, Pisa, Rom-1, LNS Catania, LNF Frascati),INGV, Tecnomare SpA • Greece:HCMR, Hellenic Open Univ., NCSR Democritos, NOA/Nestor, Univ. Athens • Netherlands: FOM (NIKHEF, Univ. Amsterdam, Univ. Utrecht, KVI Groningen) • Spain: IFIC/CSIC Valencia, Univ. Valencia, UP Valencia • UK: Univ. Aberdeen, Univ. Leeds, Univ. Liverpool, Univ. Sheffield • Cyprus: Univ. Cyprus Particle/Astroparticle institutes(16) – Sea science/technology institutes (6) – Coordinator October 11, 2005 Univ. Wisconsin, Madison

  33. Example (NIKHEF): • Advantages: • higher quantum efficiency • better timing resolution • directional information • almost 4 sensitivity • less penetrators The future: KM3NeT First studies running since a few months Detector studies at Erlangen (S. Kuch) Example: inhomogeneous km3 detector 102 1 effective area factor ~3 better for E < 1 TeV homogeneous km3 detector with same # cylinders 10-2 10-4 10-6 102 102 103 104 105 106 107 neutrino energy October 11, 2005 Univ. Wisconsin, Madison

  34. Conclusions • ANTARES: • Compelling physics arguments for ANTARES • Shower reconstruction very important; algorithms with good performance available • MILOM: data readout is working as expected; in situ timing calibration sufficient to reach angular resolution < 0.3o for E > 10 TeV • Line0: mechanical structure water tight and pressure resistant; losses in optical fibres at interface ) solutions available • Installation of first complete string about Jan. 2006;Completion of the whole detector until 2007 Well prepared for physics date to come in 2006 • KM3NeT: future km3-scale -telescope in the Mediterranean • km3-scale  telescope on the Northern Hemisphere complementary to IceCube at the South Pole • 3 year EU funded Design Study (~20 M€): expected start beginning 2006 October 11, 2005 Univ. Wisconsin, Madison

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