THE ANTARES NEUTRINO TELESCOPE: CURRENT STATUS AND FIRST RESULTS 12th Topical Seminar on Innovative Particle and Radiation Detectors ( 07 10 June 2010 Siena, Italy Harold Yepes-Ramírez IFIC (CSIC-UV), Valencia (Spain) On behalf of the ANTARES collaboration http://antares.in2p3.fr
NEUTRINO AS A NEW MESSENGER FROM THE DEEPEST UNIVERSE ν not deflected, nor absorbed γ p absorbed CMB deflected and absorbed Protons are deflected by magnetic fields (Ep< 1019 ev). Galactic sources Extra-galactic sources UHE protons interact with the CMB (Ep> 1019 ev 30 Mpc) Neutrons decay (~10 kpc at E ~ EeV). MicroQuas ars AGN s GRB s Origin of cosmic rays (CR) 1020 ev? CR acceleration mechanism? Origin of relativistic jets? Dark matter? Photons interact with the EBL (~100 Mpc) and CMB (~10 kpc). Neutrinos are neutral weakly interactive particles and they can come from dense astrophysical objects at large distances SGR s 2 Siena (Italy), June 7th7th-10th!2010 Large mass detectors required
DETECTION PRINCIPLE IN NEUTRINO TELESCOPES PMT array νµ µ W N X Cherenkov light from µ 42 νµ µ θν µ Interaction 1.5 Eν [ TeV] Main Main detection detection channel: channel: ννµµ relativistic relativistic µµ Cherenkov Cherenkov light light in in aa cone νee and detected) cone ((ν and ννtt can can also also be be detected). detected). 3 1.2 TeV Muon crossing the detector (SIMULATION) ) Reconstruction of µ trajectory (~ ν) from timing and position of PMT hits
THE ANTARES COLLABORATION University of Erlangen Bamberg Observatory University/INFN of Bari University/INFN of Bologna University/INFN of Catania LNS Catania University/INFN of Pisa University/INFN of Rome University/INFN of Genova NIKHEF (Amsterdam) KVI (Groningen) NIOZ Texel CPPM, Marseille DSM/IRFU/CEA, Saclay APC, Paris LPC, Clermont-Ferrand IPHC (IReS), Strasbourg Univ. de H.-A., Mulhouse IFREMER, Toulon/Brest C.O.M. Marseille LAM, Marseille GeoAzur Villefranche ITEP, Moscow Moscow State Univ IFIC, Valencia UPV, Valencia UPC, Barcelona ISS, Bucarest 7 COUNTRIES 28 INSTITUTES ~ 150 SCIENTISTS AND ENGINEERS 4
THE ANTARES NEUTRINO TELESCOPE 14.5 m 45 Storey 3D of 3D array array of ~885 ~885 active active PMTs. PMTs. 12 12 detection detection lines. lines. 25 25 storeys storeys // line. line. 33 PMTs PMTs // storey storey (detection (detection units). units). 40 40 km km off off Toulon Toulon coast coast (France). (France). 100 m Junction box Link cables ~60 m 2500 m depth 5
THE ANTARES NEUTRINO TELESCOPE Deployment and connection Lines 1-2: 2006 Lines 3-5: 01 / 2007 Lines 6-10: 12 / 2007 Lines 11-12: 05 / 2008 6 Some line has been repaired along the time (i.e L12) Deep water operations have been a success (i.e MEOC). Siena (Italy), June 7th7th-10th 2010 Regular maintenance of in-situ infrastructure.
THE ANTARES NEUTRINO TELESCOPE Basic detector element 1 2 STORE Local Control Module (LCM): Ti cilinder Front-end electronics Clock board, tilt/compass ARS card (2 / PMT): analogic signal processing and digitization. Time and amplitude of signal. Trigger system. Y Ti frame Support structure 1. Optical beacon with blue LEDs (LOB): 4 / line (F2, F9, F15, F21) Timing calibration Optical properties monitoring 2. Optical beacon with green LASER (LB): 2 / throughout the detector (bottom L7, L8) Timing calibration Positioning Hydrophone (Rx): Acoustic positioning 7 Optical module (OM): 10 Hamamatsu PMT (TTS 1.3 ns) 17 glass sphere (gel, optical coupling) high pressure resistant µ-cage (earth magnetic field shield) Internal LED monitor TT of PMT
THE BACKGROUND AT THE ANTARES SITE Two Two kinds kinds of of background background at at the the ANTARES ANTARES site: site: 1. 1. Physical Physical Background Background :: cosmic cosmic rays rays (atmospheric (atmospheric µµ and and νν). ). 40K 2. 2. Optical Optical Background: Background: bioluminescence bioluminescence and and 40 K decay decay (sea (sea environment): environment): Continuous Continuous component component for for long long term term average). average). 40 40K K (~60 (~60 khz) khz) and and for for bioluminescence bioluminescence (~40 (~40 khz, khz, Random Random component component for for spontaneous spontaneous bursts bursts from from bioluminescence bioluminescence (~MHz). (~MHz). MILOM only MILOM & L1 L1 & L2 ANTARES 5 Lines ANTARES 10 Lines Full ANTARES MILOM out Cable Fault 4 years of data taking 8
ANTARES FRONT -END ELECTRONICS: THE ANALOGUE RING FRONT-END SAMPLER Signals from a PMT are processed by the so-called Analogue Ring Sampler (ARS) When the signal has an amplitude > 0.3 phe (L0 threshold) its arrival time and charge are digitized. The time stamp is given by a counter periodically reset from shore and incremented by a 20 MHz clock synchronized to the signals received from 9 the shore.
ANTARES FRONT -END ELECTRONICS: TRIGGER LEVELS FRONT-END On shore Off shore 3rd LEVEL TRIGGER: the whole data flow can not be written to disk (>1 GB/s). A refined software trigger running in a computer farm on shore looks in all directions for light signals compatible with a muon track. When a trigger is found, a Physics Event is saved to disk (data flow reduced to ~ 100 kb/s). Other triggers operate in parallel: Galactic Centre, cluster of storeys and multi-messenger On shore trigger. Off shore Interlink cables 2nd LEVEL TRIGGER: Based on combinations of first level triggers. Following a 2nd level trigger the full detector will be read out. All data is sent to shore by means of multiplexed Gigabit links. 1st LEVEL TRIGGER: A coincidence between any two OMs in a single storey or a high amplitude signal (> 3 phe) in the OM Digitized. Interlink cables 10
THE ANTARES DETECTOR POSITIONING SYSTEM REAL TIME POSITIONING Acoustic positioning system + set of tiltmeters and compasses. Transceivers (RxTx) on the bottom of the lines, 4 autonomous transponders around the apparatus. 5 hydrophones (Rx) per line at specific heights. Tiltmeter and compass per storey, sound velocimeters (various depths). RECONSTRUCTION OF THE LINE SHAPE GLOBAL χ2 FIT TO LINE SHAPE MODEL (BEHAVIOUR OF LINE: SEA CURRENT) hydrophone Acoustic transceiver Hydrophone position relative to line base location (20 days) Acoustic transceiver Resolution better than 10 cm 11
THE ANTARES DETECTOR TIMING CALIBRATION Absolute time resolution: Universal time for each event Master clock system time uncertainty << required time to correlate with astrophysical events OM 1 Relative time resolution : OM 0 σtts TTS of PMTs (σ~1.3 ns) σwater Water optical properties (σ~1.5 ns) σelec Coming from electronics (σ<0.5 ns) OM 2 OM-OM Time differences (12 lines) Required calibration precision 1 ns Onshore calibration (dark room) Offshore calibration (clock + optical beacons) Angular resolution 0.3º (for Eν ν > 10 TeV ) Including the acoustic position resolution and the ν-µ angle RMS ~0.5 ns OB 12
THE ANTARES DETECTOR Optical properties monitoring Propagation depends on the optical properties of the sea water impact on the reconstruction efficiency. Transmission length of light is computed from the exponential fit to the collected signal hits by the PMTs, as a function of the distance (Nhits*R2 Vs R ) when a LOB flashes the line. The transmission length has been computed for two differents wavelengths: 470 nm and 400 nm. Lblue ~ 55-58 m LUV ~ 36-38 m 13
EXPECTED PERFORMANCE: NEUTRINO EFFECTIVE AREA Definition of effective area The effective area relates the measured rate with the incoming flux: Ndet=Aeff * Time * Flux For Eν<100 TeV, Aeff grows with energy due to the increase of the interaction cross section and the muon range. Ndet = Number of neutrinos detected. Aeff = Neutrino effective area. Time = Observation time. Flux = Neutrino incoming flux. For Eν>100 TeV the Earth becomes opaque to neutrinos. 14
EXPECTED PERFORMANCE: ANGULAR RESOLUTION Definition of angular resolution: Difference between the real and the reconstructed track. For Eν<10 TeV, the angular resolution is dominated by the ν-µ angle. For Eν>10 TeV, the resolution is limited by track reconstruction uncertainties. 15
SELECTED RESULTS RECONSTRUCTED DOWN -GOING DOWN-GOING MUON Example of a reconstructed down-going Height Dat a muon detected in all 12 detector lines: Trigger hit Other hit + Used in fit Hit Time 16 Reconstructed data
SELECTED RESULTS RECONSTRUCTED UP -GOING UP-GOING MUON Example of a reconstructed up-going muon (i.e. a Height neutrino-induced candidate) detected in 6/12 detector lines: Dat a Trigger hit Other hit + Used in fit Hit time 17 Reconstructed data
SELECTED RESULTS NEUTRINO EVENTS 2007 2008 atmospheric muons atmospheric muons Year Detector setup Life days 2007 5 Lines 168 2008 9/10/12 Lines 174 2009-2010 12 Lines > 341 18 ν events (upwards) 168 582 > 1062 (3.1/day)
SELECTED RESULTS POINT -LIKE SOURCES SEARCHES POINT-LIKE 1. Binned method: Cone (circular shape) Pr * Fixed-source search: the el im source position is taken as in ar the cone centre. y * All sky search: each event is taken as the cone centre. ** The cone size is optimized to 5 line dataset get sensitivity the best signal/background estimate ratio. 2. 19 Unbinned method: Expectation maximization (EM) pattern recognition algorithm that analytically June 7th2010 7th-10thin maximizes Siena the (Italy), likelihood finite mixture models
SUMMARY ANTARES detector was completed in May 2008: The first operational and largest neutrino telescope in the northern hemisphere Detector operation and calibration under control Exciting physics program ahead: Over one thousand neutrino-induced muons already reconstructed Astronomical sources, multi-messenger approach, dark matter models and other analysis ongoing. A multidisciplinary deep-sea research infrastructure. 20
BACKUP SLIDES
SELECTED RESULTS: The future, KM3NeT concept νµ µ 22 Array of optical modules (OM) sensing Cherenkov light Instrumented volume ~1 km3 Sensitive to all ν flavours Eν > 0.1 GeV Angular resolution : min 0.1o for Eν > 10 TeV Acceptance: o up-going tracks, upjune to7th10 Siena (Italy), -10th 2010 7th above horizon