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Olaf Scholten KVI, Groningen For the NuMoon collaboration

Radio detection of UHE Neutrinos off the Moon. Olaf Scholten KVI, Groningen For the NuMoon collaboration. Principle of the measurement. Cosmic ray. Detection: Westerbork antennas. 10 7 km 2. 100MHz Radio waves. Radio emission Mechanisms. In air: Geo-synchotron radiation

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Olaf Scholten KVI, Groningen For the NuMoon collaboration

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  1. Radio detection of UHE Neutrinos off the Moon Olaf Scholten KVI, Groningen For the NuMoon collaboration EPNT 06

  2. Principle of the measurement Cosmic ray Detection: Westerbork antennas 107 km2 100MHz Radio waves EPNT 06

  3. Radio emission Mechanisms • In air: Geo-synchotron radiation • Coherent emission in Atmosphere • LOPES • In matter: Askaryan effect • Coherent Čerenkov emission in • ice, salt, rock, …. • FORTE, RICE, SALSA, GLUE, EPNT 06

  4. ~2 m Cosmic ray ~10 cm shower Wave front Askaryan effect: Coherent Cherenkov emission • Leading cloud of electrons, v  c Typical size of order 10cm Coherent Čerenkov for ν 2-5 GHz cos θc =1/n , θc=56o for ∞ shower length • Length of shower, L  few m Important for angular spreading EPNT 06

  5. Spreading around Cherenkov-cone Old : n=1.8 New : GHz MC calculations Sine profile L=1.7 m , E=1020 EPNT 06 O.S. etal., Astropart.Phys. 2006

  6. Cosmic rays, Position on Moon Calculations for Ecr=4 1021 eV With decreasing ν : - increasing area - increasing probability ∫over surface Moon D ν-3 Partial Detection probability Normalized distance from center EPNT 06

  7. Detection Limits, Cosmic rays Minimum Flux for detecting 1 count/100h Detection threshold = 500Jy • Decreasing ν: • Increasing threshold like ν-1 • Increase sensitivity like ν-3 EPNT 06

  8. EM Shower (80%) ne e • Long EM shower • EM= 36 cm/sqrt(E/1015 eV) Shower length ~ 60 m (E/1019 eV)1/3 Hadronic Shower (20%) Relatively short Neutrino Showers above 1020 eV Landau Pomeranchuck Migdal effect J. Alvarez-Muniz, E. Zas, P.L. B434 (98)396, Phys.Rev.D62(2000)63001 Shorter showers give larger angular spread seminar

  9. Detection Limits, Neutrinos Present results compared with that of GLUE experiment (@2.2GHz) Waxman-Bahcall EPNT 06

  10. NuMoon Experiment @ WSRT Use Westerbork radio observatory • Advantages: • 117-175 MHz band • 12--25 m diameter dishes • 5 degree field of view • 40 M samples/sec (PuMa2) • Polarization information Measurements have started !! EPNT 06

  11. NuMoon Experiment @ WSRT Use Westerbork radio observatory Simultaneously: 2 strips on the Moon @ 4 frequency bands EPNT 06

  12. NuMoon Experiment @ LOFAR • Total collecting area 0.5 km2 • Cover whole moon, • Sensitivity 25 times better than WSRT. • Bands: • 30-80 MHz (600 Jy) • 115-240 MHz (20 Jy) Start: 2008 EPNT 06

  13. Cosmic Rays Sensitive to flux beyond GKZ limit Detection threshold taken at Fdet= 25 Fnoise Δν=20 MHz , 4 bands ν=140 MHz WSRT: Fdet = 15,000 Jy LOFAR: Fdet = 500 Jy EPNT 06

  14. Neutrinos WSRT, 500 hours 2 counts LOFAR, 30 days 40 counts Theoretical predictions: Waxman-Bahcall limit GZK induced flux Phys.Rev.D64(04)93010 Topological defects AstroPhys. J. 479(97)547 EPNT 06

  15. Status experiment Observation time granted at WSRT - 100h per half year, total 500h - 60 h Observation already; Data are being analyzed, Part of LOFAR Key Science Program 2008 ? EPNT 06

  16. Observations raw data time amplitude Frequency spectrum After Removing RFI 20 kHz, low resolution 1.5 kHz, high resolution EPNT 06

  17. Future: SKA,LORD 1 year observation, LFB: 100-300 MHz MFB: 300-500 MHz EPNT 06

  18. Conclusions • NuMoon @ WSRT: • 117-175 MHz band • Large field of view • Polarization information Future: NuMoon @ LOFAR Within 100 hours competitive Sensitivity to cosmic rays and neutrinos NuMoon NuMoon collaboration: KVI: Jose Bacelar, Ad van den Berg, O.S. Astron: Robert Braun, Ger de Bruyn, Heino Falcke, Ben Stappers, Richard Strom (also UvA,RUG,RU) EPNT 06

  19. SKA-Hadrons EPNT 06

  20. LORD efficiency for neutrinos EPNT 06

  21. Angular spread EPNT 06

  22. Additional Radio-absorbtion length= λ/ν[GHz]: default: λ=9 m Stopping power, default: X0 = 22.1 g/cm2 EPNT 06

  23. sensitivity to top-soil EPNT 06

  24. Vacuum 100 MHz θc Cosmic particle interaction • Particle hits Moon (radius=1700 km; area = 6π 106 km2): • protons interacts at surface • neutrinos inside • Transmission through Moon material λr= 9[m] /  [GHz] = 4m (at 2.2 GHz) • Transmissivity across Moon surface – vacuum boundary 60 km @ 1021 eV 6 km @ 1024 eV Angular spread emitted power Δθc≈λ/ℓ Hadronic component: Δθc= 2.5 (3/) = 750 (at 0.1 GHz) Case: Shower @ 2.50 with surface EPNT 06

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