Neutrino Extended Submarine Telescope with Oceanographic Research -------------- Kilometer3Neutrino Telescope NESTOR – a status reportand KM3NeT – a short status report Presented by Petros A. Rapidis National Center for Scientific Research “Demokritos” Athens, Greece On behalf of the NESTOR and KM3NeTcollaborations Describing the work of many, and also the work of others Presented on May 22, 2008 at the Milos Symposion on “Physics of Massive Neutrinos” Milos, Greece, May 19-23, 2008
Outline: • A description of the NESTOR project • A few words about the 2003 run and what we learned from this • The KM3NeT project – status and outlook • NESTOR plans for the near future : • The NuBE proposal - Site studies - Deployment work NESTOR Collaboration University of HamburgUniversity of Kiel University of Athens National Observatory of Athens – NESTOR Institute for Deep Sea Research, Technology and Neutrino Astroparticle Physics University of CreteNCSR “Demokritos” Hellenic Open University Aristotelian University of ThessalonikiUniversity of Patras Bureau of Oceanological Engineering & Institute For Nuclear Research, Russian Academy of Sciences Sholokov Open University University of Bern CERN University of HawaiiLawrence Berkeley National Laboratory
NESTOR is an effort towards building a neutrino telescope in the area off the coast of the Southern Peloponnesus, the easternmost and deepest of the three areas under consideration for KM3NeT 2400m 4500 m - 5100 m 3500m Toulon Capo Passero Pylos
~4,000m from the surface ~400m Original ideas about a NESTOR full detector Follows the DUMAND work (1975-1995) and is the progenitor of the Mediterranean projects. Had a very uneven history with periods of very little funding, but despite these problems has had some significant success and leaves behind it a significant legacy. Driven by the assumption that one has to minimize the wet-mateable connections
NESTOR TOWER 32 m diameter 30 m between floors 144 PMTs Energy threshold as low as 4 GeV 20 000 m2 Effective Area for E>10TeV
Hamamatsu PMT R2018-03 (15”) • Benthos spheres • μ-metal cage • power supply The 2003-Detector
The Cable Deployment: June 2000 ElectroOptical cable to shore(18 fibers +1 conductor) Deployed in June 2000 by the cableship MAERSK-FIGHTER (ALCATEL- TELEDANMARK) Cable was damaged during laying because of ship’s problems. Cable landing has been completed and first three km have been buried 2 m inside the bottom sand. NESTOR Star Deployment (March 2003)
Coincidence rate for OMs as measured at a depth of 3800m with 1pe thresholds The points represent the data, the solid line the Monte Carlo estimation including background and the dashed line the Monte Carlo estimation for the contribution of the atmospheric muons. 4 fold rate is 0.25 Hz for this 12 PMT node.
The measured vertical muon intensity I0 and the index a, at a depth of 3800 m water equivalent, are
KM3NeT Conceptual Design Report for a Deep‐Sea Research Infrastructure Incorporating a Very Large Volume Neutrino Telescope in the Mediterranean Sea University of Aberdeen, United Kingdom; University of Aix‐Marseille II and CPPM, Marseille, France ; University of Amsterdam, The Netherlands; APC, Paris, France ; University ofAthens, Greece ; CEA Saclay, IRFU & UVSQ , France ; CNR –ISMAR, Ancona, Italy ; CSIC, Valencia, Spain ; University ofCyprus ; Dublin Institute For Advanced Studies, Ireland; University ofErlangen, Germany ; Université de Haut Alsace‐GRPHE, Mulhouse, France ; Hellenic Centre for Marine Research, Greece; Hellenic Open University, Patras, Greece; INFN & University of Bari, Italy ; INFN & University of Bologna, Italy; INFN & University of Catania, Italy; INFN & University of Genova, Italy; INFN Laboratori Nazionali del Sud, Catania, Italy; INFN Laboratori Nazionali di Frascati, Italy; INFN & University of Napoli, Italy; INFN & University of Pisa, Italy ; INFN & University of Roma 1, Italy ; IFREMER, France ; Istituto Nazionale di Vulcanologia, Italy; Institut pluridisciplinaire Hubert Curien, Strasbourg, France ; Institute of Space Sciences, Machurele‐Bucharest, Romania;University of Kiel, Germany ; KVI and University of Groningen, The Netherlands ;University of Leeds, United Kingdom; University of Liverpool, United Kingdom; National Center of Scientific Research “Demokritos”, Athens, Greece; NIKHEF, Amsterdam, the Netherlands ; Koninklijk Nederlands Instituut voor Onderzoek der Zee(NIOZ), the Netherlands ; NOA / NESTOR, Pylos, Greece ; University of Sheffield, United Kingdom; Tecnomare, Venice, Italy ; University of Utrecht, the Netherlands; University of Valencia, Spain ; Universidad Politécnica Valencia/ IGIC, Spain
KM3NeT: From the idea to a concept 11/2002 4/2008 2/2006 9/2006 9/2005 3/2004 First consultations of ANTARES, NEMO and NESTOR KM3NeT on ESFRI Roadmap The KM3NeT Conceptual Design Report Design Study proposal submitted KM3NeT on ESFRI List of Opportunities Begin of Design Study
Major achievements • Science & technology • Successful prototype deployments by NEMO and NESTOR • Installation and operation of ANTARES A large deep-sea neutrino telescope is feasible! • Politics & funding • Endorsement by ESFRI and ApPEC • Funding through EU: Design Study, Preparatory Phase • Funding through national authorities:pilot projects, commitments for KM3NeT • Towards construction • Strong collaboration • Design concepts in CDR
The reference detector • Sensitivity studies with a common detector layout • Geometry: • 15 x 15 vertical detection units on rectangular grid,horizontal distances 95 m • each carries 37 OMs, vertical distances 15.5 m • each OM with21 3’’ PMTs Effective area of reference detector This is NOT the final KM3NeT design!
Science case revisited • Astroparticle physics with neutrinos • “Point sources”: Galactic and extragalactic sources of high-energy neutrinos • The diffuse neutrino flux • Neutrinos from Dark Matter annihilation • Search for exotics • Magnetic monopoles • Nuclearites, strangelets, … • Neutrino cross sections at high(est) energies • Earth and marine sciences • Long-term, continuous measurements in deep-sea • Marine biology, oceanography, geology/geophysics, …
Point source sensitivity • Based on muon detection • Why factor ~3 more sensitive than IceCube? • larger photo-cathode area • better direction resolution • Study still needs refinements
Diffuse fluxes • Assuming E-2neutrino energy spectrum • Only muonsstudied • Energy reconstruction not yet included
Configuration studies • Various geometries and OM configurations have been studied • None is optimal for all energies and directions • Local coincidence requirement poses important constraints on OM pattern
KM3NeT design goals • Sensitivity to exceed IceCube by “substantial factor” • Core process: nm+N m+X at neutrino energies beyond 100 GeV • Lifetime > 10 years without major maintenance, construction and deployment < 4 years • Some technical specifications: • time resolution 2 ns • position of OMs to better than 40 cm accuracy • two-hit separation < 25 ns • false coincidences dominated by marine background • coincidence acceptance > 50% • PM dark rate < 20% of 40K rate
Optical modules: standard or directional A standard optical module, as used in ANTARES Typically a 10’’ PMT in a 17’’ glass sphere A segmented anode and a mirror system allow for directional resolution First prototypes produced
… or many small photomultipliers … • Basic idea: Use up to 30 small (3’’ or 3.5’’) PMTs in standard sphere • Advantages: • increased photocathode area • improved 1-vs-2 photo- electron separation better sensitivity to coincidences • directionality • Prototype arrangements under study
Quasar 370 (Baikal) … or hybrid solutions • Idea: Use high voltage (~20kV) and send photo electrons on scintillator;detect scintillator light with small standard PMT. • Advantages: • Very good photo-electron counting, high quantum eff. • large angular sensitivity possible • Prototype development in CERN/Photonis/CPPM collaboration
Mechanical structures • Extended tower structure: like NESTOR, arm length up to 60 m • Flexible tower structure: like NEMO, tower deployed in compactified “package” and unfurls thereafter • String structure: Compactified at deployment, unfolding on sea bed • Cable based concept: one (large) OM per storey, separate mechanical and electro-optical function of cable, compactified deployment
Deep-sea infrastructure NEMO junction box design • Major components: • main cable & power transmission • network of secondary cableswith junction boxes • connectors • Design considerations: • cable selection likely to be drivenby commercial availability • junction boxes: may be custom-designed, work ongoingin NEMO • connectors: Expensive, reduce number and/or complexity
Deployment: On the surface … • Deployment operations require ships or dedicatedplatforms. • Ships: Buy, charter or use ships of opportunity. • Platform: Delta-Berenike,under construction in Greece, ready summer 08 Delta-Berenike: triangular platform, central well with crane, water jet propulsion
… and in the deep sea Commercially available ROVs • Deep-sea submersibles are likely needed for • laying out the deep-sea cable network • making connections to detection units • possibly maintenance and surveillance • Remotely operated vehicles (ROVs) available for a wide range of activities at various depths • Use of autonomous undersea vehicles (AUVs) under study
The associated science installation • Associated sciencedevices will be installed at variousdistances aroundneutrino telescope • Issues: • interfaces • operation withoutmutual interference • stability of operationand data sharing • Synergy effects
The candidate sites • Locations of the three pilot projects: • ANTARES: Toulon • NEMO: Capo Passero • NESTOR: Pylos • All appear to be suitable • Long-term site characterisationmeasurements performed and ongoing • Site decision requires scientific, technological and political input
The KM3NeT Preparatory Phase • “Preparatory Phase”: A new EU/FP7 funding instrument restricted to ESFRI projects. • KM3NeT proposal endorsed, funded with 5 M€,coordinated by Emilio Migneco / LNS Catania • 3-year project, 3/2008 – 2/2011; kick-off meeting in Catania, 10-13 March 2008 • Major objectives: • Initiate political process towards convergence(includes funding and site selection/decision) • Set up legal structure and governance • Strategic issues: New partners, distributed sites, extendibility • Prepare operation organisation & user communities • Organise pre-procurement with commercial partners • Next-step prototyping
Timeline towards construction Note: “Construction” includes the final prototyping stage
NESTOR Looking to the near future…. What can we do before the big one comes in ?!
…meanwhile … a • a GRB duration is of the order of 100 seconds
Neutrino Burst Experiment – a quick look for AGN – very high energy neutrino coincidences This drawing is to scale 300 m
Some simple considerations : Cherenkov light produced for 1 cm in water is ~200 photons in the 350-550 nm range Let us consider the case of a 100 TeV m ( 1014 eV) Range in water (km) = 4.0 x ln (1+E(TeV)) (i.e. 10 TeV ~ 9 km, 100 TeV ~ 18 km ) Thus a m on the average is accompanied by a ‘bundle’ of particles - 100 TeV / (18 km x 1 MeV/cm) ~ 60 particles (assuming they are minimum ionizing and have a de/dx of 1 ~MeV/cm) (n.b. a better simulation gives 77 particles) In passing: a 100 TeV electron (e.g. from from NC interaction, and given Xrad = 36 cm) will give rise to a dense shower with a length of L ~ 10 m , i.e. ~40 000 particles. Also a t is quite similar to an electron or muon The Optical Module is a 37 cm diameter sphere. In a 37 cm length with 200 ph/cm there will be ~ 10^4 photons produced by a 100 TeV m Light at a node 300 m away –Project to a cylinder A=2p R(300m)L(37cm) ~ 6x106 cm2 Thus we have 0.0015 photons/cm2 and for a 15" PMT of cathode area of 1080 cm2 We expect 1.5 photoelectrons. Now let us use a quantum efficiency of 20% and an overall efficiency for transmission losses, reflections in the glass etc. of 50% and take into account that the node has 16 OM’s 2.4 photoelectrons per node, i.e. can be seen !
At 100 TeV neutrinos begin to be absorbed by the earth, thus one has to start looking up. So the crucial question is : can you handle the flux of downgoing cosmic ray induced muons ? As shown earlier at a depth of 4 km with the floor of NESTOR (12 OM) the 4-fold rate is .25 Hz for downgoing m. Thus for a 16 OM node it is ~1 Hz. For an active window of 3 ms rate 1Hz x 1Hz x 3x10-6 s = 3x10-6 s-1 or 3x10-4 in 100s GRB are ~300 per year = 10-5 s-1 or 10-3 in 100 s So for a 100 s window fake is 3x10-4 x 10-3 = 10-7 in a year long run is the fake rate.
2 node trigger with E>65 GeV for m passing between stings nodes Waxman paper says that there should be 10-100 nm of 1014 eV per GRB for 1km2 So we can hope for 5-50 of such events per year (or more if the situation is more favorable).
Continuation of Site Studies (also as part of the KM3NeT effort) Light Absorption Measuring System To study sedimentation – fouling … Autonomous – complements sediment trap studies. Summary of sediment trap studies
Bioluminescence work 0 40 0 5000
Extensive measurements of deep sea currents Pylos 4500 m deep site The deep currents have very low velocities that rarely exceed 6 cm/s. In general, the flow at the Pylos site of 4500 m depth is northward and 90% of the time is below 4 cm/s, and at the 5200 m deep site is southward but substantially weaker, with 95% of the time the current speed being below the instrument’s measurement threshold Pylos 5200 m deep site
Light transmission in the water Is there a significant l dependence ? Published data for ‘pure’ water … Older measurements (See Uli’s talk) 1 .01 Absorption Coefficient (m-1) For l = 460 nm .01 .004 l=300nm l=700nm
Water Transparency Measurements (in situ) Light Intensity Measuring System ● 2 Sources: 8 LEDs in 2 groups 1. 375nm, 420nm, 450nm, 495nm 2. 383nm, 400nm, 470nm, 525nm ● Detector: 2 Photodiodes Area: 18 mm x18 mm Type: Hamamatsu S633701 ● Distances between source and detector: 10 m, 15 m, 17 m, 22 m. Data on board of the RV Aegeon on May 24. Looks good ! But not fully digested yet ….
The Delta-Bereniki deployment platform A versatile dedicated vessel Under reconstruction – engines are mounted and she will be re-floated soon. (In a month ?)
Heave compensated crane bridge. She will be able to hold position and allow work up to the end of Beaufort scale 4 sea (frequent white horses, 30 km/hour wind, 1 m waves)