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http://antares.in2p3.fr. Recent Results from the ANTARES Neutrino Experiment. P.Vernin CEA Saclay, IRFU On behalf of the Antares collaboration. ANTARES shore station. 40 km submarine cable. 22 Institutes from 7 European countries. -2500m. ANTARES Collaboration & detector site. Bucarest.
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http://antares.in2p3.fr Recent Results from the ANTARES Neutrino Experiment P.Vernin CEA Saclay, IRFUOn behalf of the Antares collaboration
ANTARES shore station 40 km submarine cable 22 Institutes from7 European countries -2500m ANTARES Collaboration & detector site Bucarest
Understanding production mechanism (‘cosmic accelerators’) of HE cosmic rays • Study very energetic objects: • galactic: SN remnants, microquasars, ... • extragalactic: GRB, AGN,… • Search for Dark matter (wimps) • Exotic (magnetic monopoles, ...) Binary systems Micro-quasars The ANTARES Physics Goals SNR GRB AGN Neutralino Annihilation
Neutrino detection principle m (~ n) trajectory ANTARES detection principle 3D PMT array nm p, a p m Cherenkov light from m gč nm g 43° 2500 m depth Measurement : Time, position & amplitude of hits m interaction n
~70 m The 12 string Antares Telescope • 25 storeys / line • 3 PMTs / storey • 900 PMTs 450 m 14.5 m 40 km to shore 100 m Junction Box Interlink cables Anchor/line socket
Basic detector element: storey Optical Beacon for timing calibration (blue LEDs) 1/4 floors 17” glass sphere 10” PMT Ham. R7081-20 14 stages Local Control Module (in the Ti-cylinder) Hydrophone RX
m n ANTARES Expected performance labs ~ 60 m (26 m) @ 470 nm (379 nm) leff (scattering)~ 300 m (100 m) @ 470 nm (370 nm)
2001 – 2003: Main Electro-optical cable in 2001 Junction Box in 2002 Prototype Sector Line (PSL) & Mini Instrumentation Line (MIL) 2003 ANTARES Construction Milestones • 2005 – 2006: • Mini Instrumentation Line + OMs (MILOM)running since 12 April 2005 • Line 1 running since March 2006,first complete detector line 2006Line 1 • 2006-2007 • Lines 2 to 10 + instrumented lines deployed and connected. Start to take physics data • Mid-2008+: Physics with full detector !
Field view of telescopes Mediterranean Sea, 43o North 2/3 of time: Galactic Centre AMANDA/IceCube South Pole 0.5 sr instantaneous common view 1.5 sr common view per day M. Circella – Status of ANTARES 9
Counting rate of a single PMT (median rate) 15 min. integration time
Acoustic positioning system 25 Position of hydrophone relative to line base location 20 14 8 20 day period March 2007 1 AutonomousTransponders Measured position resolution < 10 cm
Coincidence rates from 40K decays 10.5 ± 0.4 Hz 40K coincidence rate from Gaussian fit: 13.0 ± 0.5 Hz 13.0 ± 0.5 Hz Simulation: 12 Hz ± 4 Hz (sys)
LED Beacon measurements of OM timing resolution Time of signal in OMs relative to reference PMT 3 OMs Time difference between signals from 2 OMs in a storey (0.52 = 0.75 ns) • Electronics + calibration < 0.5 ns - TTS in photomultipliers ~ 1.3 ns - Light scattering + chromatic dispersion in sea water ~ 2 ns Limitation for angular resolution 0.2o – 0.3o 36 LEDs + reference PMT
Muon Signals This plot shows absorption of atmospheric muons in water and provides a major cross-check of the apparatus calibration
Atmospheric muon tracks • Run 21240 / Event 12505 • Zenith θ= 101o • P(c2,ndf) = 0.88 • Triggered hits • Hits used in fit • Single hits + Reconstruction with 1 line (poor sensitivity to azimut ): Altitude vs Time Hyperbola Algorithm minimizes χ2to find zenith angle of track Antarespreliminary μ Hit altitude (relative to mid detector) [m] Hit time [ns]
Atmospheric muon tracks • Triggered hits • Hits used in fit • Single hits + Antarespreliminary • 22753 / 3880 • q= 180o z [m] • P(c2,ndf) = 0.35 μ t [ns]
The first neutrino with 10 strings Preliminary
Zenith angle distribution Atmospheric muons (0.1 Hz) 5 lines, 120 days With quality cuts 78 neutrinos Atmospheric neutrinos Candidates (0.7/day)
10 lines analysis (new) Data: Dec 2007 – Apr 2008; Ag runs : 100 active days Multi line Single line 88 neutrino 208 neutrino
Diffuse neutrino flux sensitivities Bartol2004+Naumov et al (PQPM) W&B limit/2 (transparentsources) W&B W&B
Conclusions and Outlook • ANTARES is the largest neutrino telescope in the Northern hemisphere • Detector is working well, within design specifications • Technical challenge successfully mastered • Data collection started • Neutrino candidates detected • 10 detection lines taking data since December 2007 • 12 detection line apparatus to be completed next week • The last two lines already deployed • Operation for science 5 years • R&D for acoustic HE neutrino detection • Multidisciplinary platform for associated sea sciences • Milestone towards a KM3 underwater detector.
Examples of seismic events M. Circella – Status of ANTARES VLVnT08 23
Multidisciplinary research activities: sea current recording Data from the ADCP are currently being analyzed by NIOZ 24
10 lines Sci.Linux 4 upgrade & Trigger modification Data quality Trigger rate: ~1 Hz (5 lines) ~2-3 Hz (10 lines) 19106 detected with the 5 Lines Date (2007) Date (2007) 25
Majority Multi-directional efficiency 200 m 200 m 180 m 5 local coincidences or large pulses 350 m log10(E) 100 m Standard trigger… TRIGGER: • 5 L1 • causal connection between L1: • L0: PMT hit above 1/3 p.e. • L1: local coincidence (2 L0 in the OM triplet in t<20 ns) or a large pulse (> 3 p.e.) 26
Current status of the site Installed N IL07 L1 L5 L2 L3 L9 L4 L7 L6 L8 L11 • Deployed • Connection May 2008 Submarine cable to shore L10 L12 seismometer 100 m Junction box 27
Acoustic positioning system Muon signals Coincidences between signals on adjacent storeys Pedestal = background (including 40K, biolum.) Peak amplitude due to muon flux Peak offset, width and shape = function of muon angular distribution, spectrum, … Data/MC ratio ≈ 1.13
Line shape determination using tiltmeter-compasses & acoustic triangulations 5 position sampling points (hydrophones) & 25 gradients (tiltmeter& compass data from each storey) allow reconstruction of line shape Measured position resolution < 10 cm 29
upward Event display Characteristic pattern in function of zenith angle and point of closest approach between detection line and track Downward (background) 30
Atmospheric muons Rate of reconstructed atmospheric muons: • Agreement between simulations and data is within 10% 31
ANTARES effective area Ndet=Aeff × Time × Flux Effective area Effective area • The effective area relates the measured rate to the incoming flux: • Effective area for steady sources (visibility of the detector included). • Energy integration limits from 500 to 107 GeV. • Different spectral indexes for the source emission are considered. 32
ANTARES 1y Sensitivity to point sources with energy spectrum E-2 Sensitivity and upper limits for ANTARES compared with other experiments. andE-2 fluxes from point-like sources versus declination 33
Expected sensitivity on diffuse flux of HE • MACRO: Astropart.Phys.19:1-13,2003. • Baikal Astropart. Phys. 25, 140 (2006). • AMANDA-II (807 d) Phys.Rev.D76:042008,2007 • IceCube: Astrop. Phys. 20 (2004) 507 • WB= Waxman & Bahcall, PRD59 (1999) • MPR98, PRD 63 (2001) • SDSS91: Phys. Rev. Lett. 66(91)2697 MACRO BAIKAL ANTARES (1y) AMANDA II ANTARES (3y) ICECUBE 34