Icefishing for… Neutrinos Francis Halzen University of Wisconsin http://icecube.wisc.edu/ http://pheno.physics.wisc.edu/~halzen Seeing: Cosmic Messengers • Visible light (Alhassan 1000) • Light of other wavelengths (radiowaves, X-rays…) • Neutrinos Neutrinos, they are.
Download ReportTranscript Icefishing for… Neutrinos Francis Halzen University of Wisconsin http://icecube.wisc.edu/ http://pheno.physics.wisc.edu/~halzen Seeing: Cosmic Messengers • Visible light (Alhassan 1000) • Light of other wavelengths (radiowaves, X-rays…) • Neutrinos Neutrinos, they are.
Icefishing for… Neutrinos Francis Halzen University of Wisconsin http://icecube.wisc.edu/ http://pheno.physics.wisc.edu/~halzen Seeing: Cosmic Messengers • Visible light (Alhassan 1000) • Light of other wavelengths (radiowaves, X-rays…) • Neutrinos Neutrinos, they are very small, they have no charge and have no mass, and do not interact at all. John Updike AMANDA NEUTRINO SKY AMANDA •Neutrino Astronomy •AMANDA: the First NeutrinoTelescope •Proof of Concept for IceCube Visible CMB 400 microwave photons per cm3 1 TeV = 1 Fermilab GeV g-rays Flux Radio Energy (eV) / / / / / / TeV sources! / / / cosmic / / rays / / / / / / n The Universe 400 microwave photons per cm3 positron electron New Window on Universe? Expect Surprises Telescope User date Intended Use Actual use Optical Galileo 1608 Navigation Moons of Jupiter Optical Hubble 1929 Nebulae Expanding Universe Radio Jansky 1932 Noise Radio galaxies Micro-wave Penzias, Wilson 1965 Radio-galaxies, noise X-ray Giacconi … 1965 Sun, moon Radio Hewish, Bell 1967 Ionosphere Pulsars g-rays military 1960? Thermonuclear explosions Gamma ray bursts 3K cosmic background neutron stars accreting binaries Acceleration to 1021eV? ~102 Joules ~ 0.01 MGUT dense regions with exceptional gravitational force creating relativistic flows of charged particles, e.g. •annihilating black holes/neutron stars •dense cores of exploding stars •supermassive black holes Cosmic Accelerators High Energy requires many Tesla (~10 Tesla) • large magnetic field • over large distances cfr Fermilab many kilometers (~4 km) Supernova shocks expanding in interstellar medium Crab nebula Active Galaxies: Jets 20 TeV gamma rays Higher energies obscured by IR light VLA image of Cygnus A Gamma Ray Burst Neutrino Astronomy to the Rescue… black hole radiation enveloping black hole Sources of Neutrinos • The Earth’s atmosphere: every second one thousand neutrinos, made in the interactions of cosmic rays with nitrogen and oxygen nuclei, pass through your body-- one in a lifetime interacts • The sun: 1014 stream through our body every second (even at night) • Supernovae: 20 neutrinos detected from a dying star in 1987 • Beyond the sun? Requires kilometer-scale neutrino detectors But Neutrino Astronomy Began with Solar Neutrinos 30 Yrs Ago! •Superkamiokande’s portrait of the Sun in neutrinos: compilation of the directions of all neutrinos observed • Discovery of neutrino mass! R. Svoboda, LSU We did see 20 neutrinos from one supernova in 1987 SN1987A • Measurements of many neutrino properties with only ~20 events (mass, ….) • Several mysteries remain awaiting a new observation Hubble, NASA How large a neutrino telescope? • 1 neutrino per lifetime (30,000 days) in our body (100 kg or 0.1 m3 ) means • 0.00003 per day in 0.1 m3 or • 3 per day in 100,000 m3 ( roughly SuperK with 40x40x40 m3) 0r • 300,000 per day in 109 m3 or 1 km3 (we actually will detect 300 per day because we limit ourselves to neutrinos above 100 GeV as opposed to 1 GeV which means 100 1.7). “I have done a terrible thing… • …I have invented a particle that cannot be detected” Wolfgang Pauli • Fermi comes to the rescue • Reines: an atomic bomb? • Reines: an atomic reactor! Neutron beta decay electron proton Neutron neutrino Inverse beta decay neutrino neutron Proton electron or muon •Infrequently, a cosmic neutrino is captured in the ice, i.e. the neutrino interacts with an ice nucleus •In the crash a muon (or electron, or tau) is produced Cherenkov muon light cone Detector •The muon radiates blue light in its wake •Optical sensors capture (and map) the light interaction neutrino Copyright © 2001 Purdue University Optical Module Photomultiplier: 10 inch Hamamatsu Active PMT base Glass sphere: Nautillus Mu metal magnetic shield Another example: velocity muon > velocity light Neutrino Astronomy • Energy balance of the Universe: roughly equal amounts of light and neutrinos • 1950’s: proposals to use neutrinos rather than (the particles of) light as astronomical messengers • 1970’s: first attempts to construct neutrino telescopes in deep ocean water • 1987: ice proposed as a detector at UW • 1998: AMANDA detects first neutrinos Neutrino sky seen by AMANDA 40 Data 35 Atmosphericn MC 30 25 events 20 15 10 5 0 -1 -0.9 -0.8 -0.7 -0.6 -0.5 -0.4 -0.3 -0.2 -0.1 • Monte Carlo methods verified on data • ~ 300 neutrinos from 130 days of B-10 operation (Nature 410, 441, 2001) 0 cos() Cos() The Challenge is Technological • Needle in a haystack: have to find each neutrino in a background of more than one million background events • Do this at a rate of 100 muons per second • Deploy a particle physics detector in a hostile environment • Solutions demonstrated with AMANDA Atmospheric Muons and Neutrinos Lifetime: 135 days Observed Data Predicted Neutrinos 1,200,000,000 4574 Reconstructed upgoing 5000 571 Pass Quality Cuts (Q ≥ 7) 204 273 Triggered We were lucky • Light travels more than 100 meters in the ultrapure, sterile ice • Scattering of the light is manageable • We use the existing infrastructure of the National Science Foundation’s South Pole Research Station • Makes the construction of the ultimate kilometer-scale neutrino observatory possible AMANDA II - the full detector 120m horizontal neutrino detection possible ...online 2001 analysis 2 recent events October 7, 2001 October 10, 2001 ...online 2001 analysis Zenith angle comparison with signal MC atmospheric muons atmospheric n‘s real-time filtering at Pole real-time processing (Mainz) Left plot: 20 days (Sept/Oct 2001) 90 ncandidates above 100° 4.5 ncandidates / day (data/MC normalized above 100°) IceCube IceTop AMANDA South Pole Skiway • 80 Strings • 4800 PMT • Instrumented volume: 1 km3 (1 Gt) • IceCube is designed to 1400 m detect neutrinos of all flavors at energies from 107 eV (SN) to 1020 eV 2400 m The IceCube Collaboration Institutions: 11 US and 9 European institutions (most of them are also AMANDA member institutions) 1. 2. 3. 4. 5. 6. 7. 8. 9. 10. 11. 12. 13. 14. 15. 16. 17. 18. 19. 20. Bartol Research Institute, University of Delaware BUGH Wuppertal, Germany Universite Libre de Bruxelles, Brussels, Belgium CTSPS, Clark-Atlanta University, Atlanta USA DESY-Zeuthen, Zeuthen, Germany Institute for Advanced Study, Princeton, USA Dept. of Technology, Kalmar University, Kalmar, Sweden Lawrence Berkeley National Laboratory, Berkeley, USA Department of Physics, Southern University and A\&M College, Baton Rouge, LA, USA Dept. of Physics, UC Berkeley, USA Institute of Physics, University of Mainz, Mainz, Germany Dept. of Physics, University of Maryland, USA University of Mons-Hainaut, Mons, Belgium Dept. of Physics and Astronomy, University of Pennsylvania, Philadelphia, USA Dept. of Astronomy, Dept. of Physics, SSEC, PSL, University of Wisconsin, Madison, USA Physics Department, University of Wisconsin, River Falls, USA Division of High Energy Physics, Uppsala University, Uppsala, Sweden Fysikum, Stockholm University, Stockholm, Sweden University of Alabama, Tuscelosa, USA Vrije Universiteit Brussel, Brussel, Belgium µ-event in IceCube AMANDA II IceCube: -> Larger telescope area -> Superior detector 1 km Muon Events Eµ= 6 PeV Eµ= 10 TeV Measure energy by counting the number of fired PMT. (This is a very simple but robust method) PeV t (300m) nt t t decays South Pole South Pole Dark sector Skiway AMANDA Dome IceCube Planned Location 1 km east South Pole Dark sector Skiway AMANDA Dome IceCube Optical Cherenkov Neutrino Telescope Projects ANTARES La-Seyne-sur-Mer, France NEMO Catania, Italy BAIKAL Russia DUMAND Hawaii (cancelled 1995) NESTOR Pylos, Greece AMANDA, South Pole, Antarctica Superkamiokande 1761 upward going muons (through-going and stopping) from 1264 live days (April 96-May 00) 1200 m2 acceptance area Lake Baikal, NT-200: The Site 1366 m ANTARES Deployment Sites Thetys Marseille La Seyne sur Mer Toulon Existing Cable Marseille-Corsica Demonstrator Line Nov 1999- Jun 2000 42°59 N, 5°17 E Depth 1200 m New Cable (2001) La Seyne-ANTARES ANTARES 0.1km2 Site 42°50 N, 6°10 E Depth 2400 m ~ 40 deployments and recoveries of test lines for site exploration 0.1 km2 Detector with 900 Optical Modules , deployment 2002- 2004 ANTARES 0.1km2 detector The End New Window on Universe? Expect Surprises Telescope User date Intended Use Actual use Optical Galileo 1608 Navigation Moons of Jupiter Optical Hubble 1929 Nebulae Expanding Universe Radio Jansky 1932 Noise Radio galaxies Micro-wave Penzias, Wilson 1965 Radio-galaxies, noise X-ray Giacconi … 1965 Sun, moon Radio Hewish, Bell 1967 Ionosphere Pulsars g-rays military 1960? Thermonuclear explosions Gamma ray bursts 3K cosmic background neutron stars accreting binaries Lake Baikal: atmospheric neutrinos „Gold plated neutrino event, 4-string stage (1996) NT-200: zenith angle distribution 234 days in 1998/99 19 hits 1.5 km ANTARES 2 0.1km Detector Shore station Optical module hydrophone ~60m float Compass, tilt meter 2400m Electro-optic submarine cable ~40km 300m active Electronics containers Readout cables ~100m anchor Junction box Acoustic beacon ne+ e W m + nm 6400 TeV AMANDA: • since 1992 we have deployed 24 strings with more than 750 photon detectors (basically 8-inch photomultipliers). • R&D detector for proof of concept: 375 times SuperK instrumented volume with 1.5% the total photocathode area. • detects more than 5 muon-neutrinos per day with energy near or in excess of 1 TeV. accelerated proton… crashes into light around black hole…. g producing radiation and neutrinos n The Oldest Problem in Astronomy: • No accelerator • No particle candidate (worse than dark matter!) • Not photons (excludes extravagant particle physics ideas) What Now? With 103 TeV energy, photons do not reach us from the edge of our galaxy because of their small mean free path in the microwave background. g + gCMB + e + e Neutrino Astronomy to the Rescue… • Energy balance of the Universe: roughly equal amounts of light and neutrinos • 1950’s: proposals to use neutrinos rather than (the particles of) light as astronomical messengers • 1970’s: first attempts to construct neutrino telescopes in deep ocean water • 1987: ice proposed as a detector • 1998: AMANDA detects first neutrinos