1. June 9, 2002 Hallewell ANTARES RICH2002 1 ANTARES : A deep-sea 0.1 km² neutrino telescope Greg Hallewell – CPP Marseille Representing the Antares Collaboration RICH2002 Workshop on Ring Imaging Cerenkov Detectors, Pylos, Greece, June 5-9, 2002

2. June 9, 2002 Hallewell ANTARES RICH2002 2 ANTARES Collaboration  University of Sheffield  CPPM, Marseille  DSM/DAPNIA/CEA, Saclay  C.O.M. Marseille  IFREMER, Toulon/Brest  LAM, Marseille  IReS, Strasbourg  Univ. de H.-A., Mulhouse  ISITV, Toulon  Observatoire de la Côte d’Azur  University of Bari  University of Bologna  University of Catania  LNS – Catania  University of Rome  University of Genova  IFIC, Valencia  NIKHEF, Amsterdam  ITEP, Moscow  Universitat Erlangen

3. June 9, 2002 Hallewell ANTARES RICH2002 3 Contents 1)Detector Overview 2)Detector Principal Components 3)Site Selected and Ocean Backgrounds 40 K, bioluminescence, light absorption 4) “Demonstrator” Line 7 PMTs,  hyperbolic reconstruction 5) Time and Position Calibration  reconstruction from PM signals with arrival times known to ~1 ns acoustic transponder net, LED and laser beacons 6) Sea Instrumentation Line current profile, salinity, light absorption, P,T, sound velocimeter 7) “Sector” Line Deployment 8) Conculsions

4. June 9, 2002 Hallewell ANTARES RICH2002 4 neutrino muon Cerenkov light isochrone in seawater ANTARES Detector interaction Lattice of 900 PMTs in “Optical Modules”  track direction from arrival time of light Neutrino direction:        0.7 o / E 0.6 (TeV)  energy from energy loss and range Typ. 1  per PMT 40m from  trajectory (1.1) Detection Principle A 0.1km 2 detector should record ~ 1-2000 medium energy cosmic neutrinos per year (E > 300 GeV).

5. June 9, 2002 Hallewell ANTARES RICH2002 5 Low Energy (10 GeV < E < 100 GeV) Medium Energy (10 GeV < E < 1 TeV) High Energy (E > 1 TeV) oscillations (observation of first oscillation minimum from atmospheric ) neutralino search (signal from annihilating WIMPs in the Earth, the Sun and the Galaxy) from galactic and extra- galactic sources (x-ray binaries, micro-quasars, SNR, AGN, GRB) (1.2)Scientific Motivation (1.2) Scientific Motivation +Oceanography - measurements of oceanographic parameters of the deep sea - studies of bioluminescence

6. June 9, 2002 Hallewell ANTARES RICH2002 6 0.1 km² Detector : Expected performance  Including effects of reconstruction and selection, PMT TTS, positioning, timing calibration accuracy and scattering.  Below ~10 TeV angular error is dominated by -  physical angle.  Above ~10 TeV angular accuracy is better than 0.4° (reconstruction error).   E /E  3 (E  1 TeV)  Below E ~ 100 GeV energy estimation via muon range measurement. Angular resolution Angular resolution Energy resolution Energy resolution

7. June 9, 2002 Hallewell ANTARES RICH2002 7 ANTARES 0.1km 2 detector 60 m 10 lines of 90 PMTs 6 sectors/line (350m) 5 storeys/sector (60m) 3 PMTs/storey (12m) 350 m 100 m 12 m Junction box Readout cables 40 km cable to shore 2400m Local electronics Optical Module triplet Hydrophone (1 / sector) Time calibration LED Beacon (1 / sector)

8. June 9, 2002 Hallewell ANTARES RICH2002 8 (2) Principal Components: A Detector Line Buoy Electro-mechanical Cable - mechanical support (kevlar core) with optical fibres and power conductors 3 Optical Modules/storey - 10” PMT, active base, LED internal calibration system 1 Local Control Module; -“ARS” front end ASIC (amplitude, 1GHz time sampling)/PMT; -Tiltmeter (line shape in current) & compass (line torque) Sea bed Bottom String Structure - acoustic string release, acoustic positioning transponder String Control/Power Module: - string power supplies - data acquisition: 6 sectors  DWDM  6x1Gb/s on 1 fibre Interlink cable, - wet-mateable connector: 4 optofibres+ 2 power conductors 12 m 100m 90 PMTs/line  6 sectors of 5 storeys of 3 PMTs Master Local Control Module: - acoustic positioning (1 hydrophone / sector) - data acquisition: 5 storeys  sector ethernet 1Gb/s LED Beacon (4 per line)

9. June 9, 2002 Hallewell ANTARES RICH2002 9 Glass sphere (Nautilus) Photomultipler: 10” Hamamatsu R7081-20 Mu metal magnetic shield Active (C-W) PMT Base (ISEG) (2.1) Principal Components: Optical Module & PM LED pulser Optical gel Quantum Efficiency L att (Spher e) (LoBoro): cm L att (Gel): cm Sensitive area > 500 cm 2 ; 14 stages; 2.10 8 Gain @ 2500V; Transit Time: typ 60ns @ 1750V (–2.5ns/100V) (Regularly Measured by LED pulser on each tube) Transit Time Spread:  1.3 ns(spec.):V fixed; Dark Count Rate (0.3 pe equ. Thr.): < 10kHz; Pulse Shape: Rise Time < 5 ns, FWHM < 12 ns

10. June 9, 2002 Hallewell ANTARES RICH2002 10 Cerenkov signature: Timing of cone arrival at PMTs on strings: hyperbolic fit PMT positions need to be known to ~20 cm (1 ns in seawater) # OM hits depends on range of muon Detector Positioning Resolution Hits to  <1 ns to be small compared with dispersive limits in seawater of ~ 1.6 ns over ~ 40 m optical path length achieved by: acoustic transponder net: string profile in undersea current, inclinometers (pitch, yaw) & compasses (heading: OM rotation angle around string ): (1 per “storey”) Timing Resolution on OM LED Pulser in each OM, LED & Laser beacons:Goal < 0.5 ns Some Detector Specificatons

11. June 9, 2002 Hallewell ANTARES RICH2002 11 (2.3) Principal Components: “Analog Ring Sampler” front-end digitizer The Analog Ring Sampler (ARS) chip performs the complex front-end functions: ~$10/chip, 250mW Constant 1GHz analog sampling of PMT Anode, Anode/5, Dynode 11, and 20 MHz CLOCK signals Dynamic Range  4V (~ 60spe) Configurable pulse-shape discrimination to tag complex shapes (“Waveform”) which will be fully digitized. For simple pulses (SPE-like) only Charge and Time information is measured.  t ~400 ps 2 x 8 bit ADCs working in ll to digitize events upon readout request (trigger) High speed (20Mb/s) serial port transfers digitized events to the central DAQ LCM processor.

12. June 9, 2002 Hallewell ANTARES RICH2002 12 (2.3) ARS Timing Resolution (May ’02) Timing Resolution: electronic signals directly into ARS Timing Resolution: attenuated laser signals  OM  ARS

13. June 9, 2002 Hallewell ANTARES RICH2002 13 (3) The ANTARES Site Antares Site: 40Km SE Toulon (42º50’N, 6º10’E) Depth 2400m Shore Base La Seyne-sur-Mer -2400m 40 km Submarine cable

14. June 9, 2002 Hallewell ANTARES RICH2002 14 Land Cable ( Fibre optics ) Detector Assembly Hall (Foselev Marine) (3.1) Installations in La Seyne sur Mer Power Hut Les Sablettes La Seyne sur Mer Chambre de test Zone d’intégration Stockage Salle de contrôle Préparation Shore Station Villa Michel Pacha Submarine cable (10/01) ( Fibre optics + power )

15. June 9, 2002 Hallewell ANTARES RICH2002 15 1 5 3 2 4 6 9 7 8 10 13 1112 14 Submarine cable: ALCATEL Site inspection: “Cyana” (Manned Submersible) (3.2) Site: Sea Floor Layout, Vehicle Resources Line sea floor configuration Line connections Victor Victor (ROV) Wet-Mateable Connector (@250 bar H 2 O) At Line Sea Anchor

16. June 9, 2002 Hallewell ANTARES RICH2002 16 (3.3) Site Evaluation: Sedimentation Biofouling m Angles from 50-90º m Expected transmission loss <1.5%/yr ANTARES PMTs look down: (45-225º)] PIN Diode Detectors Test Stand

17. June 9, 2002 Hallewell ANTARES RICH2002 17 Variable distance between LED and PMT “ascenseur” (3.4) Water optical properties: Transparency Season [473nm] [375nm] abs (m)  scatt eff (m) July 9869  1272  4 March 9961  1231  11 June 0049.7  0.3 48.4  0.3 294  3 305  31 July 9922.0  0.1 104  52 102  16 Sept 9925.1  0.2 25.4  0.2 120  2 108  3 June 0028.0  0.1 134  2 124  3 Need in-situ on line monitoring (instrumentation line)

18. June 9, 2002 Hallewell ANTARES RICH2002 18 (3.5) Water Properties: Optical Backgrounds (1)Cerenkov Light: from Atmospheric (Downgoing)  ’s (~400  cm -1 : 300< <600 nm) (  E   ~350 GeV:  rate 10-30 Hz) (10 6 * rate of upgoing  from  (2) Sea Optical background: ~ 60 kHz on 10” PMT mainly 40 K Bioluminescence bursts (o~MHz), locally-correlated (typ 1 storey, 3 PMTs) ~ few % of the time + Bottom Current Dependent Bottom Currents Measured  typ. < 5% dead time/ PMT

19. June 9, 2002 Hallewell ANTARES RICH2002 19 (4) Full Demonstrator Line (’98-’00) m First (350m) line equipped with 16 pairs of Glass Spheres –Summer 98 : successful deployment test at 2300m depth performed with Dynamical Positioning ship –December 99-June 00 : demonstrator equipped with 7 PMTs + acoustic positioning system linked to shore station by electro- optical cable – 50,000 atmospheric  ’s reconstructed m December 98 : successful undersea electrical connection test of detector anchor performed at 2400m depth by IFREMER submarine vehicle “Nautile” (ex-Titanic expeditions)

20. June 9, 2002 Hallewell ANTARES RICH2002 20 50,000 events with 7-fold coincidences (>1300 reconstructed events per day) Zenith from 4 par. Hyperbolic fit of depth vs. PMT signal timestamp 40 K hits filtered out by software MC agrees with data (multimuons, ghosts) (4.1) Muons on “Demonstrator line” No reconstructed events  < 45º

21. June 9, 2002 Hallewell ANTARES RICH2002 21 (5.1) 40-60 kHz Acoustic positioning system ~ 1 cmInter-Transponder  3 cmRang.-Transponder ~1 cmInter-rangemeter Accuracy (  )Devices 4 transponders 1 of 3 rangemeters Time (min) 5cm Y coord. Range 3-2 (m) Require Positioning Accuracy < 1 ns (1 ns = 22cm in seawater). Triangulation allows  5 cm accuracy Self-Cal.

22. June 9, 2002 Hallewell ANTARES RICH2002 22 InterLink cable to shore station (6) The Sector Line: Deployment for late ‘02 SCM/SPM, acoustics Rx/Tx LCM+acoustics Rx1 MLCM LCM LCM+acoustics Rx2 Buoy BSS LED beacon Junction Box Optical module frame Optical Module Local Control Module

23. June 9, 2002 Hallewell ANTARES RICH2002 23 100m Sound Velocimeter ADCP Current Profiler CTDCSTAR Acoustic Positioning Modules (receivers) Optical Beacon Acoustic Positioning Modules LASER Beacon (7) The Mini Instrumentation Line Electro Mechanical Cable 2 fibres for DAQ, 1 for clock Electro Mechanical Cable 3 fibres for DAQ Mechanical Cable JB 2 fibres for DAQ 1 for clock  Current profiler –ADCP 300 kHz of RDI –Orientated downwards –Current profile for ~150 m depth –Resolution: ~ 0.5 cm/s –RS232 interface  Temperature/Salinity: –Model 37-SI MicroCAT –Resolution : 10 -4 °C, 10 -4 S/m –RS232 interface  Transmissionmeter –CSTAR of Wetlabs –Measures over 25cm large azimuthal range for abs, scatt

24. June 9, 2002 Hallewell ANTARES RICH2002 24 ANTARES Timeline Collaboration formed EO Cable deployed and tested Sector Line mechanical test Sector Line deployment Deployment of lines 1 to 10 0.1km 2 detector to complete Site evaluation programme to select a suitable site “Demonstrator” line deployment and operation Technical design report completed

25. June 9, 2002 Hallewell ANTARES RICH2002 25 (8) Conclusion ANTARES has made excellent progress over the past 4 years : –Site environmental characterisation OK –Tests of marine technologies under control –Deployment and operation of Demonstrator String –Down-going muons reconstructed in demonstrator –Expanding Collaboration ANTARES has entered Phase II of its programme : the design, the installation and commissioning of a 10-string 0.1 km² detector in 2002-2004 -main electro-optical sea cable successfully deployed - sector line deployment Sept 2002 Major step forward towards a km-scale neutrino telescope in the Mediterranean

26. June 9, 2002 Hallewell ANTARES RICH2002 26 THE END (possible extras follow)

27. June 9, 2002 Hallewell ANTARES RICH2002 27 Angular Resolution The angular resolution of the detector depends on –reconstruction algorithms –selection programs –timing accuracy (PMT timing error, positional error on OMs, timing calibration error) m Above 10 TeV the neutrino pointing accuracy is 0.4 degrees or better including scattering effects m Note: at high energy the error is dominated by reconstruction errors, at low energy by the angle between the muon and neutrino

28. June 9, 2002 Hallewell ANTARES RICH2002 28 Glass sphere (Nautilus) Photomultipler: 10” Hamamatsu R7081-20 Mu metal magnetic shield Active (C-W) PMT Base (ISEG) (2.1) Principal Components: Optical Module LED pulser Optical gel

29. June 9, 2002 Hallewell ANTARES RICH2002 29 (2.2) Principal Components: Hamamatsu R7081-20 Characteristics Sensitive area > 500 cm 2 ; 14 stages; 2.10 8 Gain @ 2500V; Transit Time: typ 60ns @ 1750V (–2.5ns/100V) ( Regularly Measured by LED pulser on each tube ) Transit Time Spread:  1.3 ns(spec.):V fixed; Dark Count Rate (threshold 0.3 pe equ.): < 10kHz; Pulse Shape: Rise Time < 5 ns, FWHM < 12 ns Quantum Efficiency L att (Sphere) (LoBoro): cm L att (Gel): cm T > 88%

30. June 9, 2002 Hallewell ANTARES RICH2002 30 (2.4) Data Flow Architecture OFFSHORE Communication between offshore LCM processors (MPC8xx) and onshore farm (~100 PCs) using Ethernet protocol via optical fibres All data to shore- if bandwidth saturated, an OFFSHORE TRIGGER can be activated to reduce dataflow to just local coincidences Bandwidth of data transmission maximised using DWDM Dense Wavelength Division Multiplexing - Each sector of a string assigned a colour (7 colours/string) - At SCM all colours multiplexed to one pair of fibres ONSHORE The colours of each line are demultiplexed All data of current time frame (10ms) assigned to single CPU Each PCs run the DataFilter program which accepts events with time correlated hits LCM MLCM LCM OM 7 Mb/s 25 Mb/s SCM 125 Mb/s 750 Mb/s 7.5 Mb/s 75 Mb/s 75 kb/s 125 Mb/s DWDM CPU DataWriter Ethernet Switch 7.5 Gb/s from other lines JB “Local Control Module” “Master (sector) Local Control Module” “String Control Module”

31. June 9, 2002 Hallewell ANTARES RICH2002 31 Energy Resolution m Different techniques are used in different energy regimes  Below 100 GeV the energy can be estimated from the range of the muon:  E ~ 3 GeV m Use of the hadronic shower energy may improve energy resolution at medium and low E m At energies above 1 TeV the muon energy loss is dominated by catastrophic energy loss (bremss., pair production) which increases with energy. A truncated mean parametrization is used m The corresponding energy resolution is typically a factor of 3 to 4 for E > 1 TeV

32. June 9, 2002 Hallewell ANTARES RICH2002 32 (5.2) Optical Beacons for timing calibration precision 0.5 ns: cf arrival time precision of OM ~ 1 ns LED (Blue) Beacon (4 per line ) (illuminates several stories of neighboring lines): MiniPMT for time reference LED pulsers 5.10 6  8.10 7  per pulse @ 470nm, T rise 1.8  2 ns; FWHM 4.5  6.5 ns Green Laser Beacon (Instrumentation line anchor) (illuminates lower stories of most lines): Fast pin diode for time reference Nanolase NG-10120-120 laser head + Diffuser 532 nm; 1  J/pulse, T rise 1.8  2 ns; FWHM 0.8 ns

33. June 9, 2002 Hallewell ANTARES RICH2002 33 (3) The ANTARES Site Antares Site: 40Km SE Toulon (42º50’N, 6º10’E) Depth 2400m Shore Base La Seyne-sur-Mer -2400m 40 km Submarine cable  3.5  sr of sky covered  0.5  sr overlap with Amanda  Galactic Centre surveyed  Need neutrino telescopes in both hemispheres

34. June 9, 2002 Hallewell ANTARES RICH2002 34 Variable distance between LED and PMT “ascenseur” (3.4) Water optical properties: Transparency Season [473nm] [375nm] abs (m)  scatt eff (m) July 9869  1272  4 March 9961  1231  11 June 0049.7  0.3 48.4  0.3 294  3 305  31 July 9922.0  0.1 104  52 102  16 Sept 9925.1  0.2 25.4  0.2 120  2 108  3 June 0028.0  0.1 134  2 124  3 Need in-situ on line monitoring (instrumentation line)

35. June 9, 2002 Hallewell ANTARES RICH2002 35 abs ~ 55-65 m ; scat > 100 m at large angles   Water Transparency