ANTARES: a system of underwater sensors looking for neutrinos

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 km2 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 Introduction

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

4. protons E>1019 eV (10 Mpc) neutrinos gammas (0.01 - 1 Mpc) protons E<1019 eV Why neutrino astronomy? Cosmic accelerator 1 parsec (pc) = 3.26 light years (ly) Photons:absorbed on dust and radiation Protons/nuclei:deviated by magnetic fields, reactions with radiation M. Ardid for ANTARES Collaboration 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 ~ 1011 ν/cm2 • 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 Introduction

6. 3D PMTarray p, a nm p m Cherenkov light from m gč nm g 43° Sea floor m interaction Reconstruction of m trajectory(~ n)from timing and position of PMT hits n Detection Principle M. Ardid for ANTARES Collaboration Introduction

7. Why so large? so deep? Why …? • Why so large? Neutrino detection requires huge target massesdue 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 accuracyof the position of the optical sensors is needed (~ 10 cm) together with a good timing resolution (< 1 ns) M. Ardid for ANTARES Collaboration Introduction

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

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

10. Modular detector Modular detector  easily expandable to larger dimensions Nearby Large Infrastructures and Scientific Laboratories M. Ardid for ANTARES Collaboration Detector overview

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

12. Optical Modules M. Ardid for ANTARES Collaboration Optical Modules

13. Base LED PMT m-metal cage Gel Optical Modules Blow-up of an Optical Module Main specs • Sensitive area  500 cm2 • Transit time spread < 3.6 ns (FWHM) • Dark count (@ 1/3 SPE) < 10 kHz • Peak/valley > 2 PMT: 10” Hamamatsu R7081-20 The 900 PMT’s have been fully characterized

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

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

16. Front-end: ARS & Motherboard The PMT signals (anode and dynode D12) are processed by theAnalogueRing Sampler In the same chip are gathered ASIC full custom chip 4 x 5 mm2, 68000 transistors 200 mW under 5 V • A comparator • An integrator • A clock • A Pulse Shape Discriminator • Flash ADC (up to 1GHz sampling) • Pipe-line memory • Fast output port (20 Mb/s) Parameters adjustable via SC • 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 • 3rd one used for complementary trigger purposes M. Ardid for ANTARES Collaboration Data Acquisition system

17. LCM LCM LCM LCM MLCM 2 MLCM 1 MLCM 4 MLCM 5 MLCM 3 DAQ Board & Data Transmission The main functions of the DAQ board are: RISC m-processor • 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) •  Ethernet node Cf. next slide Bi-directional transceiver 100 Mb/s link To shore (MEOC) SCM 1 Gb/s link MUX Line 1 JB Line 2 deMUX At the level of the MLCM (i.e. sector level): At the level of the SCM (i.e. line level): • optical bi-directional signals are merged • 2 fibers (Rx and Tx) ensure the communication with the SCM • The color is different for each sector • colors are (de)multiplexed by DWDM’s • the communication with shore is done via two fibers per line through the Junction Box M. Ardid for ANTARES Collaboration Data Acquisition system

18. Slow control Managedby the main processor Messages (requests and answers) are interleaved with ARS data (same fiber) Main tasks: • Configuration of the detector (for instance ARS’s) • Supervision of the state of the detector: temperature, voltages, consumption … Dedicated m-controllerwith ADC’s and DAC’s • to measure temperatures and humidity • to command/monitor high voltages on PMT • formatting of data • an interface with compass/inclinometers TCM2 Dedicated circuit with: • 2-D inclinometers for roll and pitch measurements • 3-D magnetometers for compass bearing Main performances: • .5 to 1 for compass bearing • .2for tilt angles • 1 mT for magnetic field In combination with the acoustic positioning: reconstruction of the line shape Data Acquisition system positions in space of the optical modules

19. Calibration systems M. Ardid for ANTARES Collaboration • 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 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 Construction Milestones

21. Line 1 deployment Construction Milestones

22. ROV connection of Line 1 Pictures courtesy of IFREMER M. Ardid for ANTARES Collaboration Construction Milestones

23. Upward going muon track reconstructed (height vs. time, q = 69º) during shift 07/09 Track predicted depending on orientation Hundreds of neutrino candidates already detected Downgoing muon M. Ardid for ANTARES Collaboration Construction Milestones

24. Summary and conclusions M. Ardid for ANTARES Collaboration 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 neutrinosThank you for the attention M. Ardid for ANTARES Collaboration The End