1. ANTARES: a system of underwater sensors looking for neutrinos Miguel Ardid IGIC- Universitat Politècnica de València on behalf of the ANTARES Collaboration Introduction Detector overview Optical modules Data acquisition system Calibration system Construction milestones & schedule Summary and conclusions UNWAT – SENSORCOMM Valencia, 18th October 2007

2. ANTARES ANTARES (Astronomy with a Neutrino Telescope and Abyss environmental RESearch) Collaboration is deploying a 2500 m deep 0.1 km 2 underwater neutrino telescope in the Mediterranean Sea It is the largest neutrino telescope under construction in the northern hemisphere. The aim of the telescope is to detect high energy neutrinos, which are elusive particles expected from a multitude of astrophysical sources. ANTARES also aims to provide a research infrastructure for deep sea scientific observations. M. Ardid for ANTARES Collaboration UNWAT – SENSORCOMM Valencia, 18 th October 2007 Introduction

3. ANTARES Collaboration IFIC Valencia IFREMER,Toulon & Brest DAPNIA, Saclay IReS, Strasbourg GRPHE, Mulhouse CPPM Marseille IGRAP, Marseille COM, Marseille ITEP Moscow NIKHEF, Amsterdam KVI,Groningen Genova Bari Catania Roma Erlangen LNS Pisa Bologna Bucharest IGIC- UPV Gandia 23 Institutions from 7 European countries M. Ardid for ANTARES Collaboration UNWAT – SENSORCOMM Valencia, 18 th October 2007 Introduction

4. Why neutrino astronomy? Photons: absorbed on dust and radiation Protons/nuclei: deviated by magnetic fields, reactions with radiation 1 parsec (pc) = 3.26 light years (ly) gammas (0.01 - 1 Mpc) protons E>10 19 eV (10 Mpc) protons E<10 19 eV neutrinos Cosmic accelerator M. Ardid for ANTARES Collaboration UNWAT – SENSORCOMM Valencia, 18 th October 2007 Introduction

5. Why neutrino astronomy? Neutrinos (ν’s) are elementary particles: –Extremely small mass, no electric charge, very small interaction difficult to detect –Are produced in nuclear fusion (e.g. stars) or fission (e.g. nuclear power plants) processes –From Sun reaching Earth ~ 10 11 ν/cm 2 Neutrinos traverse space without deflection or attenuation –they point back to their sources (Search for astrophysical point sources) –they allow for a view into dense environments –they allow us to investigate the universe over cosmological distances (Search for Big Bang relics) Neutrinos are produced in high-energy hadronic processes → distinction between electron and proton acceleration. Neutrino is a good key for particle physics & cosmology –Magnetic monopoles, topological defects, Z bursts, nuclearites, … M. Ardid for ANTARES Collaboration UNWAT – SENSORCOMM Valencia, 18 th October 2007 Introduction

6.   43° Sea floor p    p,   Reconstruction of  trajectory (~ ) from timing and position of PMT hits interaction Cherenkov light from  3D PMT array Detection Principle M. Ardid for ANTARES Collaboration UNWAT – SENSORCOMM Valencia, 18 th October 2007 Introduction

7. Why so large? so deep? Why …? Why so large? Neutrino detection requires huge target masses due to the low probability of interaction → use naturally abundant materials (water, ice) Why so deep? A large shield is needed in order to avoid masking from other cosmic particles → deep inside the earth Why so many optical elements? In order to reconstruct the muon track, the Cherenkov light should be detected. Attenuation length of light in water = 52 m. Why calibration systems? For the muon reconstruction a good accuracy of the position of the optical sensors is needed (~ 10 cm) together with a good timing resolution (< 1 ns) M. Ardid for ANTARES Collaboration UNWAT – SENSORCOMM Valencia, 18 th October 2007 Introduction

8. 8 Toulon 40 km submarine cable -2475m ANTARES shore station Site Detector overview

9. ~70 m 450 m JunctionBox Interlink cables 40 km to shore 2500m 900 PMTs 12 lines 25 storeys / line 3 PMTs / storey 9 lines + IL deployed (675 PMTs) 5 lines connected and taking data (375 PMTs) Design

10. Modular detector  easily expandable to larger dimensions Nearby Large Infrastructures and Scientific Laboratories Modular detector M. Ardid for ANTARES Collaboration UNWAT – SENSORCOMM Valencia, 18 th October 2007 Detector overview

11. Hydrophone RX Local Control Module (in the Ti-cylinder) Optical Beacon for timing calibration (blue LEDs) 1/4 floors Optical Module in 17” glass sphere Storey: Basic detector element M. Ardid for ANTARES Collaboration UNWAT – SENSORCOMM Valencia, 18 th October 2007 Detector overview

12. Optical Modules M. Ardid for ANTARES Collaboration UNWAT – SENSORCOMM Valencia, 18 th October 2007 Optical Modules

13. Blow-up of an Optical Module Gel PMT  -metal cage Base LED  Sensitive area  500 cm 2  Transit time spread < 3.6 ns (FWHM)  Dark count (@ 1/3 SPE) < 10 kHz  Peak/valley > 2 PMT: 10” Hamamatsu R7081-20 Main specs The 900 PMT’s have been fully characterized

14. Data Acquisition System DAQ Hardware main hardware components in the electronics module of a storey Main processes in the DAQ system

15. Local Control Module COMPASS_MBARS_MB LCM_DAQ POWER_BOX UNIV1 Inside a Local Control Module x 3 x 4 in case of LED beacon LCM_CLOCK For some LCM’s, additional cards for:  LED beacon  Hydrophone

16. Front-end: ARS & Motherboard The PMT signals (anode and dynode D 12 ) are processed by the A nalogue R ing S ampler ASIC full custom chip 4 x 5 mm 2, 68000 transistors 200 mW under 5 V In the same chip are gathered Parameters adjustable via SC  A comparator  An integrator  A clock  A P ulse S hape D iscriminator  Gain  Gauge for PSD  Integration timing  Thresholds … The motherboard is equipped with 3 ARS’s.  By mean of a token ring, 2 of them are activated in turn reduction of dead time  3 rd one used for complementary trigger purposes  Flash ADC (up to 1GHz sampling)  Pipe-line memory  Fast output port (20 Mb/s) M. Ardid for ANTARES Collaboration UNWAT – SENSORCOMM Valencia, 18 th October 2007 Data Acquisition system

17. DAQ Board & Data Transmission The main functions of the DAQ board are:  Readout and packing of the data produced by the ARS’s.  Transmission of the resulting data through the line network.  Processing of slow control messages.  Conversion to optical signals on 1 fiber (100 Mb/s) At the level of the MLCM (i.e. sector level): RISC  -processor  Ethernet node Bi-directional transceiver Cf. next slide LCM MLCM 1 100 Mb/s link  optical bi-directional signals are merged  2 fibers (Rx and Tx) ensure the communication with the SCM  The color is different for each sector SCM MLCM 2 MLCM 3MLCM 4MLCM 5 1 Gb/s link At the level of the SCM (i.e. line level):  colors are (de)multiplexed by DWDM’s  the communication with shore is done via two fibers per line through the Junction Box MUXMUX deMUXdeMUX To shore (MEOC) JB Line 1 Line 2 M. Ardid for ANTARES Collaboration UNWAT – SENSORCOMM Valencia, 18 th October 2007 Data Acquisition system

18. Slow control Dedicated  -controller with ADC’s and DAC’s In combination with the acoustic positioning: positions in space of the optical modules Managed by the main processor Messages (requests and answers) are interleaved with ARS data (same fiber)  to measure temperatures and humidity  to command/monitor high voltages on PMT  formatting of data  an interface with compass/inclinometers Dedicated circuit with: Main performances: .5  to 1  for compass bearing .2  for tilt angles  1  T for magnetic field TCM2  2-D inclinometers for roll and pitch measurements  3-D magnetometers for compass bearing reconstruction of the line shape Main tasks:  Configuration of the detector (for instance ARS’s)  Supervision of the state of the detector: temperature, voltages, consumption … Data Acquisition system

19. Calibration systems Main calibration systems are presented in other talks: –Positioning Calibration (P. Keller’s talk) To determine and monitor the position of optical modules –Timing Calibration (F. Salesa’s talk) To know the time offsets and get a good timing resolution –Instrumentation Line + Acoustic detection (R. Lahmann’s talk) Monitor environmental and physical variables that could play a role in any system of the telescope Equipment for marine science research Study the viability of the acoustic detection of neutrinos M. Ardid for ANTARES Collaboration UNWAT – SENSORCOMM Valencia, 18 th October 2007 Calibration systems

20. Construction milestones 1996-1999: R&D and site evaluation period. 1999-2004: Prototype lines 2004-2005: Final design line evaluation: Line0 (test of mechanics) & MILOM (Mini Instrumentation Line with Optical Modules) February 2006-October 2007: 9 lines + IL deployed, 5 lines connected and operational, starts standard operation March 2008: The whole detector will be finished and ready to work at full efficiency for science operation M. Ardid for ANTARES Collaboration UNWAT – SENSORCOMM Valencia, 18 th October 2007 Construction Milestones

21. Line 1 deployment Construction Milestones

22. ROV connection of Line 1 M. Ardid for ANTARES Collaboration UNWAT – SENSORCOMM Valencia, 18 th October 2007 Construction Milestones Pictures courtesy of IFREMER

23. Downgoing muon Hundreds of neutrino candidates already detected M. Ardid for ANTARES Collaboration UNWAT – SENSORCOMM Valencia, 18 th October 2007 Construction Milestones Upward going muon track reconstructed (height vs. time,  = 69º) during shift 07/09 Track predicted depending on orientation

24. Summary and conclusions M. Ardid for ANTARES Collaboration UNWAT – SENSORCOMM Valencia, 18 th October 2007 ANTARES Collaboration pursued the challenge of building an undersea neutrino telescope as a sophisticated and precise system of underwater sensors in a hostile environment The design, construction and first results have been shown After a hard job, there is now almost half neutrino telescope operational and working within specifications, and will be completed early next year. For the first time, an undersea neutrino detector (ANTARES) “sees” neutrinos (most likely atmospherics) New challenge: KM3NeT, a cubic kilometre undersea neutrino telescope (see C. Bigongiari’s talk) Summary and conclusions

25. ANTARES: a system of underwater sensors looking for neutrinos Thank you for the attention M. Ardid for ANTARES Collaboration UNWAT – SENSORCOMM Valencia, 18 th October 2007 The End