neutrinos and the sea Els de Wolf NIKHEF Ilias Meeting, Prague, February 8 th 2005

2 KM3NeT, what is it? Design study for a Deep Sea Facility in the Mediterranean for Neutrino Astronomy and Associated Sciences Design study for a Deep Sea Facility in the Mediterranean for Neutrino Astronomy and Associated Sciences Objective: develop cost-effective design of a 1 km 3 neutrino telescope (~ 200 M€) Objective: develop cost-effective design of a 1 km 3 neutrino telescope (~ 200 M€) Participants from existing collaborations: Participants from existing collaborations: + + +…

3 Participating countries

4 Outline Purpose of -telescopes Purpose of -telescopes -telescopes in the Mediterranean -telescopes in the Mediterranean The KM3NeT project The KM3NeT project –History –Why in Mediterranean Sea –Physics Motivation –Design Requirements –Design Considerations –Challenges Gamma-Ray Bursts Active Galactic Nuclei

5 Purpose of Neutrino Telescopes Astrophysics ( -astronomy): Astrophysics ( -astronomy): –Identify point sources –Composition of jets –Origin of cosmic acceleration –Diffuse fluxes Particle physics: Particle physics: –Dark Matter searches:  Neutralinos –Monopoles –Origin of UHE-cosmic rays (extra) galactic -sources Neutralino search:  → +…

6 Dumand Baikal Amanda Icecube Neutrino Telescopes Projects Mediterrennean km 3 Antares NEMO NESTOR

7 Detection Principle Neutrino reactions (key reaction is  N   X) Cross sections and mechanisms known from accelerators Cross sections and mechanisms known from accelerators Extrapolation to high energy (> 100 TeV) uncertain Extrapolation to high energy (> 100 TeV) uncertain

8 ANTARES Flexible strings 10” PMTs, looking downwards 2500 m depth 40 km offshore Toulon 70 m between strings 14.5 m between storeys One junction box

9 Measurements from an ANTARES Prototype String Measurements from an ANTARES Prototype String Rate measurements: strong fluctuation of bioluminescence background observed Rate measurements: strong fluctuation of bioluminescence background observed Also measured: current velocity and direction, line heading and shape, temperature, humidity,... Important input for preparation and optimisation of ANTARES operation 10min Rate (kHz) time (s) ANTARES deep sea data 10min

10 NESTOR Rigid tower structure (titanium) Dry mateable connectors 15” up- and downward looking PMTs 3800 m deep Near Pylos Tower 32 m diameter 30 m between floors 144 PMTs First floor (reduced size) deployed and operated in 2003

11 NESTOR: atmospheric muon flux Zenith Angle (degrees) (1/N)dN/dcos(θ) M.C. Prediction Data Points

12 ….and comparison with others Good agreement confirms precise understanding of detector response, calibration, simulation and efficiencies

13 NEMO project 3340 m deep 80 km off shore Catania 16 arms per tower 20 m arm length Arms 40 m apart 64 PMTs per tower Up- and down-looking PMTs Wet mateable connectors Hierarchy of junction boxes

14 NEMO objectives Extensive site exploration R&D for km3: architecture, mechanical structures, readout, electronics, … Test installation foreseen with all critical components Completion expected by 2006

15 History KM3NeT July 2002: HENAP report to PaNAGIC July 2002: HENAP report to PaNAGIC  “... a km3-scale detector in the Northern hemisphere should be built to complement the IceCube detector being constructed at the South Pole.” October 2003: VLV T workshop in Amsterdam October 2003: VLV T workshop in Amsterdam  ANTARES, NEMO, NESTOR  Also industrial presentations e.g. Hamamatsu, Photonis, ETL, Saclant, Nautilus, Seacon, Ocean Design, …  March 2004: KM3NeT EU FP6 Design Study submitted March 2004: KM3NeT EU FP6 Design Study submitted

16 Why in the Mediterranean Sea? Sky view complementary to ICECUBE Sky view complementary to ICECUBE Deep sites (up to ~5000m) close to shore: Deep sites (up to ~5000m) close to shore: –shielding against atmospheric muons –good infrastructure –easy to reach by boat –short cable to shore –repair of detector line feasible Long scattering length Long scattering length –good pointing accuracy Experience of NESTOR, ANTARES, NEMO Experience of NESTOR, ANTARES, NEMO

17 KM3NeT and IceCube Complementary sky views * : Complementary sky views * : (*) ANTARES location provides a sky coverage of 3.5 p sr and an instantaneous common view with AMANDA of 0.5 p sr, and about 1.5 p sr common view per day. The Galactic centre is visible 2/3 of the time. Region of sky seen in galactic coordinates assuming 100% efficiency for 2  down KM3NeT galactic centre Not seen Mkn 501 GX339-4 SS433 CRAB VELA IceCube Mkn 501 Mkn 421 CRABSS433 Not seen

18 Scientific motivation HESS supernova remnant RXJ

19 KM3NeT Design Requirements Effective volume: 1 km3, expandable Effective volume: 1 km3, expandable Angular resolution: close to intrinsic resolution ( 10 TeV) Angular resolution: close to intrinsic resolution ( 10 TeV) Maximal angular acceptance for all possible detectable neutrino signals including down-going neutrinos at VHE Maximal angular acceptance for all possible detectable neutrino signals including down-going neutrinos at VHE Lower energy threshold of a few 100 GeV for upward going neutrinos with the possibility to go lower for from known point sources Lower energy threshold of a few 100 GeV for upward going neutrinos with the possibility to go lower for from known point sources Energy reconstruction within a factor of 2 for muon events Energy reconstruction within a factor of 2 for muon events For all neutrino flavors For all neutrino flavors Field of view: close to 4  Field of view: close to 4  Source tracking → from satellites: Source tracking → from satellites: Duty cycle close to 100% Duty cycle close to 100% Operational lifetime ≥ 10 years Operational lifetime ≥ 10 years Cost effectiveness ~ 200 M€ per km 3 Cost effectiveness ~ 200 M€ per km 3 All parameters need optimisation

20 Associated Sciences KM3Net Infrastructure will cooperate with the European Sea Floor Observatory Network KM3Net Infrastructure will cooperate with the European Sea Floor Observatory Network Long term and continuous monitoring of ocean environment around Europe: – –Environment and Security – –Geohazards – –Global change – –Biodiversity

21 Design Considerations Detector architecture Detector architecture Photo detection Photo detection Calibration Calibration Mechanics Mechanics Readout and Data Transfer Readout and Data Transfer Deployment and Sea operations Deployment and Sea operations Power distribution Power distribution Cost (~ 200 M€) Cost (~ 200 M€) Highly interconnected

22 Detector Architecture homogeneous lattice 20 x 20 x 20 downward-looking 10 “ photomultiplier tubes 20 x 60 m = 1200 m Homogenous strings?Towers? D. Zaborov at VLV T

23 Detector Architecture homogeneous lattice 20 x 20 x 20 downward-looking 10 “ photomultiplier tubes 20 x 60 m = 1200 m Homogenous strings? D. Zaborov at VLV T

24 Detector Architecture Top view 50 x 20 m = 1000 m 250 m 50 floors 20 m step 25 towers, each consists of 7 strings PMTs are directed downwards Towers? D. Zaborov at VLV T

25 Detector Architecture D. Zaborov at VLV T 200 m 16 x 40 m = 640 m 40 m 20 m Top view 16 floors with 4 PMTs each 40 m floor step 64 NEMO - towers Towers?

26 Sea Operations Rigid towers or flexible strings? Rigid towers or flexible strings? Connection in air (no ROVs) or Connection in air (no ROVs) or wet mateable connectors? Deployment from platform Deployment from platform or boat?

27 Photo Detection Glass pressure vessel < 17” Glass pressure vessel < 17” Hamamatsu 15” used by NESTOR Hamamatsu 15” used by NESTOR Requirements for photo detection: Requirements for photo detection: –High QE –Large photocathode areas –Wide angular coverage –Good single photon resolution resolution –High dynamic range Example of a device discussed: Hamamatsu HY0010 HPD Excellent np.e. resolution

28 Photo Detection Options Large segmented photocathode area with arrays of small PMTs packed into pressure housings - low cost! Large segmented photocathode area with arrays of small PMTs packed into pressure housings - low cost! Determine the photon direction via, e.g. Determine the photon direction via, e.g. –Multi-anodic PMTs plus a matrix of Winston cones

29 Readout and Data Transfer The data rate from a KM3 detector will be high - estimated at Gb/s The data rate from a KM3 detector will be high - estimated at Gb/s Questions to be addressed: Questions to be addressed: –Optimal data transfer to shore (many fibres + few colours, few fibres + many colours, etc.) –How much processing to be done at the optical module –Analogue vs. digital OMs - implies differing approaches to design of front end electronics –Data filtering will play an important role –Distribution of (raw?) data to data analysis centres One possible data distribution concept One possible data distribution concept Application of current PP GRID technologies to some of these open questions? Application of current PP GRID technologies to some of these open questions?

30 KM3NeT Challenges Design: Design: –Simplify off-shore electronics (‘all-data-to-shore’) –Separate detection and calibration functionalities? Production model: Production model: –Start construction at end of design study (TDR) –Multiple production and lines or structures –Multiple production and assembly lines or structures –Pressure and shallow water tests at production sites –Transport and deployment ‘as is –Transport and deployment ‘as is’ Site selection: Site selection: –France, Italy or Greece

31 KM3NeT Production Model? Estimated size of the production: Estimated size of the production: – optical modules –400 detector units (“lines”) –40 calibration units Start of data taking: 2012 Start of data taking: 2012 –Start design study: 2006 –Start of production: / day 12 / month 1.5 / month Production time of 3 years 5 – 6 production sites are needed

32 Final choice will depend on Final choice will depend on –Depth –Accessibility –Distance from shore –Bioluminescence rate rate –Sedimentation –Sea current –Access to high speed networks on shore –…… –Socio-political/regional considerations Site Selection ?

33 Summary Compelling scientific argument for complementing IceCube with a km 3 scale detector in the Northern Hemisphere Compelling scientific argument for complementing IceCube with a km 3 scale detector in the Northern Hemisphere The Mediterranean projects NESTOR, ANTARES and NEMO provide knowledge and experience for deep sea telescopes The Mediterranean projects NESTOR, ANTARES and NEMO provide knowledge and experience for deep sea telescopes The FP6 KM3NeT Design Study has been accepted The FP6 KM3NeT Design Study has been accepted Foreseen start of the DS early 2006 Foreseen start of the DS early 2006 Objective of the DS: TDR end 2008 Objective of the DS: TDR end 2008