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The NuMoon experiment: first results

The NuMoon experiment: first results. Stijn Buitink for the NuMoon collaboration Radboud University Nijmegen 20 th Rencontres de Blois, 2008 May 19. 10 4. ← 1 [m -2 s -1 ]. E -2.7. F(E) [ m 2 sr s GeV ] -1. ← 32 orders of magnitude . . 1 [km -2 y -1 ].

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The NuMoon experiment: first results

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  1. The NuMoon experiment: first results Stijn Buitink for the NuMoon collaboration Radboud University Nijmegen 20th Rencontres de Blois, 2008 May 19

  2. 104 ← 1 [m-2 s-1] E-2.7 F(E) [ m2 sr s GeV ] -1 ← 32 orders of magnitude   1 [km-2 y-1] ← 12 orders of magnitude  10-28 109 1021 E [eV ] The Cosmic Ray Spectrum What is the origin? Acceleration sites? Top down models? Search for sources  highest energies

  3. Propagation of cosmic rays Cronin 2004

  4. The GZK Distance The GZK Energy GZK Cutoff

  5. Search for UHE CRs and neutrino’s Flux above 1020 eV: 1 /km2/sr/century Pierre Auger Observatory 3000 km2 IceCube ~1 km3

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

  7. ~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

  8. Neutrino’s vs. CRs • CR convert all energy into hadronic shower • Neutrino: 20% of energy into electromagnetic shower • CR interacts close to surface • Neutrino can penetrate deeply

  9. Surface roughness Small scale roughness `scatters’ radiation Large scale roughness disfavours CR detection James & Protheroe 2008

  10. Spreading around Čerenkov-cone Lunar regolith: n ≈ 1.8 GHz GHz Scholten et al. 2006

  11. Reflection Spreading is diminishing internal reflection 3 GHz 100 MHz

  12. Position on Moon Calculations for Ecr=4 1021 eV Detection treshold: 500 Jy for 20 MHz bandwidth With decreasing ν : - increasing area - increasing probability ∫over surface Moon D ν-3 Partial Detection probability Normalized distance from center Scholten et al. 2006

  13. Detection off the Moon Goldstone Lunar UHE Neutrino Search (GLUE) P. Gorham et al., PRL 93, 041101 (2004) • First experiment: 12 hrs using single Parkes 64m dish in Australia: T. Hankins et al., MNRAS 283, 1027 (1996) Two antennas at JPL’s Goldstone, Calif. Tracking Station @ 2.2 GHz

  14. James & Protheroe, 2008

  15. NuMoon Experiment @ WSRT Use Westerbork radio observatory • Advantages: • 117-175 MHz band • 25 m diameter dishes • 5 degree field of view • 12 coincident receivers • 40 M samples/sec (PuMa2) • Polarization information NuMoon coll.: O.Scholten, S.Buitink, H.Falcke, B.Stappers, K.Singh, R.Strom

  16. NuMoon Experiment @ WSRT Use Westerbork radio observatory 4 frequencies

  17. Processing Pipeline • 18 TB raw time series data per 6 hr slot • Removal of narrow-band radio interference (RFI) • Dedispersion for ionosphere • Peak search • ~1% of data stored for offline processing

  18. Simulated pulse dispersed in ionosphere (TEC = 10)

  19. + raw data =

  20. + dedispersion Trigger: 4σ pulse in all four frequency bands

  21. Trigger Power Spectrum Effect successive steps in analysis Gaussian noise

  22. Prelimenary Results Analysis of 10 h 40 min data

  23. Future: Lofar Lofar High Band antennas 120-240 MHz 77 stations; 2x2 km core + outlying stations

  24. Lofar neutrino sensitivity

  25. Lofar UHE CR sensitivity

  26. Lunaska • Australia Telescope Compact Array • Undergoing upgrade • 2 GHz bandwidth; 5 antenna’s

  27. SKA & Pathfinder (ASKAP) 100 MHz – 25 GHz Small dishes for higher frequency range SKA to be build in Australia or South Africa Pathfinder in Australia Planar Aperture Arrays for lower frequency range

  28. Future sensitivity LOFAR James & Protheroe, 2008

  29. Conclusions • Radio detection of lunar showers promising technique for detection of highest energy particles • NuMoon @ WSRT sets competitive limits on UHE neutrino flux • Future missions will provide constraints for TD models • SKA will be sensitive to expected GZK flux

  30. FORTE satellite(Fast On-orbit Recording of Transient Events) • Main mission: synaptic lightning observation • Viewed Greenland ice (1997-99) • 1.9 MILLION km3 • 38 days Log-periodic antennas N. Lehtinen et al., PRD 69, 013008 (2004)

  31. Angular spread Z0~Δc~λ/L=1/Lν D. Saltzberg et al PRL 86 (2001) 2802 Askaryan effect: confirmation in sand Experiment at SLAC with beams of photons And 1010 e-/bunch: effective shower energies 0.06-1.10 1019 eV 1 Jy = 10-26 W/m2/Hz

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