SURFACE ARRAY Détecteur de surface pour ANTARES JP Ernenwein CPPM GDR 29/10/2009
ANTARES OM 14.5 m 10 PMT 350 m 25 étages ANTARES, 2475m, 3 PMT/floor 12 lines of 25 floors 885 PMTs 100 m 70 m floor JUNCTION box Basis of a line
2005 2006 Mar: MILOM 2007 Mar: L1 Sep: L2 Jan : L3-5 MILOM recovery 2008 Dec: L6-10 IL07 N IL07 L1 L5 L2 L3 L9 L4 L7 L6 L8 Câble sous marin (vers la côte) L11 L10 L12 sismomètre 100 m Boîte de jonction Connection of lines Jun: L11,12
Detection principle 3D matrix shower Cherenkov light (µ) Dynamic range : 20pe/40ns threshold ~1/3 pe required sensitivity: photo-electron 1 photo-electron 0 1 2 3 4 5 6 7 8 Charged current interaction (W) νµ νe 42 9 10 2500-5000 m γč good energy resolution (O(30%)), poor angular resolution (O(10 )) µ track: Good angular resolution (O(degree) @ E>10 TeV), Poor energy resolution (factor 2-3) Measurements time (O(ns)), amplitude (30%) & hit position(o(10 cm)) Muon track or shower measurement
Down going background events (atm muons and muons from neutrinos) m At g ck d un ro 3 dφ/dω cm-2 s-1 sr-1 Ex of diff. flux ba log [ Eν2 Flux(Eν)] Signal & background AGN 6 9 log(e/gev) 10-7 Profondeur 2400 m E > 1 TeV 10-9 10 µ atmosphere sea νµ Atm muons 106 Muons from atm neutrinos Cosmic neutrinos 10-15 10-17 cos θ µ νµ Up going background (muons from neutrinos) p µ 10-11 -13 p, α γ
Expected neutrino sources Galactic: Supernovae, Supernovae remnants, SNR RX J1713.7-3946 Aharonian et al, A.A. 449 (2006) 223-242 Crab Nebula Micro Quasars: Pulsars ν Dark Matter : neutralino annihilation in massive objects (Sun, Earth, GC) M 87, HST EXTRA GALACTIC: GRB counts s-1 8 105 4 105 0 AGN -2 time (s) 5
Current results Atmospheric muons Neutrinos & muons 341 days in 2007/2008 (5 lines, 9, 12 lines) 1062 Region for neutrinos
Current results 140 days preliminary Point source search with ANTARES in its 5 lines stage
Measurement of the position of the lines hydrophones+ tiltmeters & compas line shape Zenith Autonomous beacons + Basis of lines shape=f(sea current) Position of line anchor : acoustic measurements from boat, itself positioned with a GPS.
Angular resolution (median) kinematics reconstruction µ ν 0.3 10 TeV Can be cancelled by the uncertainty on the absolute pointing: To be measured independently : Moon shadow, cliff shadow : O(year) but free, Surface Array : O(week) but not free!
Principle of the Surface Array GPS-compas Temps & orientation & inclinaison
Atmospheric showers proton 100 TeV CORSIKA e, 30 km > 100 kev > 100 MeV hadrons > 100 MeV Threshold 100 MeV SEA level F. Schmidt, "CORSIKA Shower Images",http://www.ast.leeds.ac.uk/ ~fs/showerimages.html SEA SA 5 km
Required properties of a detection unit :,p e, 1 MIP = 2.1 MeV ~ 20 000 photons in plastic scintillator 1cm thick (REXON RP200). PMT 2 at the center + reflectors on each side: O(0.1%) detection efficiency About 20 pe detected by the PMT for a MIP @ corner Gain 3 105 (Hamamatsu R6231) threshold ~ 15 mv for one MIP Time resolution Crossing of the threshold: of a few ns
Measurement of time resolution &&20ns trigger 0.76 m signal 1m Events 1 cm 75% efficiency Threshold ~ 15 mv ~4.8 ns (walk effect not corrected) t
Implementation
Electronics (commercially available) 10 ns 1V 3 test units (50 cm x 50 cm x 1cm, 1 PMT) MATACQ T14 t => angle of shower axis
We search for some offset in the mean of and : simulations of performances event by event comparison of : zenith, azimuth of reconstructed tracks (SA vs ANTARES). Estimate of the event rate. Corsika shower simulation : protons with E in [105,5.106] GeV 5 or 8 days equivalent (55 104 showers / day). Reconstruction based on t from a least 3 scintillators requiring 4 MIPs of threshold for each (resolution ~ 3 rms for setups with ~10 detectors) : ~3 rec evts / min. Simulation made in coll with HOU (HELYCON detectors) 1000 m 2 tested distances : just above ANTARES (0m) 00 24 m 1 km apart (1000m, zenith ~ 24 ) HELYCON VLVNT08, JPE & A Tsirigotis
Results of simulations for 10 detection units Conclusion for the DU itself : CASTOR
COSTS 3.6 k per detection unit including electronics for digitization (MATACQ) 90 k for 5 effective days of sea campain FULL APPARATUS 32 Detection Units on a platform 35m x 15m or a boat (limitation: size of the vessel, electronics channels) VESSELS...
Boat or platform + boat Raymond Croze Length up to 100 m Width 20 m Castor Basis of simulations (12m x 30m) 13 m x 23 m
How to make it cheaper: electronics CPPM home made solution for electronics (under study) : from 1200 / channel to 200 /channel : re-use and adaptation of an existing solution. For each DU, the 12V required by the HT generation are provided through a coaxial cable. On the same cable is transmitted a positive logical signal built from the PMT signal (pre-amplifier inverter, x5, with time over threshold info) thresh Logical signal (~1 V) t i t i' Transmission on 20 to 50 m All 32 channels connected to a single central card sampling the signals with a 1-2 ns cell.
sampling How to make it cheaper: electronics time Size of 1 event : 400 * 32 bits = 1600 bytes. Repetition : ~ 3/minute 32 inputs Communication with PC: TCPIP 1 ns = cell 1 word of 32 bits for the 32 channels, per cell 400 words = 1 event
Steps of the project : November 2009: 4 units under test (1 MATACQ card) January 2010: 8 units (2 MATACQ card, measurement of angular resolution by splitting detector) March 2010: decision on the choice commercial electronics/home made Summer 2010: N units ready (depending of the funding) for sea operation Achievable constraint in 10 days, 32 units : 0.2 in zenith and 0.4 in azimuth.