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

3. The Cosmic Ray Spectrum What is the origin? Acceleration sites? Top down models? Search for sources  highest energies F(E) [ m 2 sr s GeV ] -1 E [eV ] 10 -28 10 4 10 9 10 21 ← 32 orders of magnitude  ← 12 orders of magnitude  ← 1 [m -2 s -1 ] 1 [km -2 y -1 ] E -2.7 

4. Propagation of cosmic rays Cronin 2004

5. GZK Cutoff The GZK Energy The GZK Distance

6. Search for UHE CRs and neutrino’s Pierre Auger Observatory 3000 km 2 IceCube ~1 km 3 Flux above 10 20 eV: 1 /km 2 /sr/century

7. Cosmic ray 100MHz Radio waves Detection: Westerbork antennas Principle of the measurement 10 7 km 2

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

9. 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

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

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

12. Reflection Spreading is diminishing internal reflection 3 GHz100 MHz

13. Position on Moon Partial Detection probability Normalized distance from center Calculations for E cr =4 10 21 eV Detection treshold: 500 Jy for 20 MHz bandwidth With decreasing ν : - increasing area - increasing probability ∫ over surface Moon D  ν -3 Scholten et al. 2006

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

15. James & Protheroe, 2008

16. 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

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

18. 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

19. Simulated pulsedispersed in ionosphere (TEC = 10)

20. + raw data =

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

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

24. Prelimenary Results Analysis of 10 h 40 min data

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

26. Lofar neutrino sensitivity

27. Lofar UHE CR sensitivity

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

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

30. Future sensitivity LOFAR James & Protheroe, 2008

31. 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

32. FORTE satellite (Fast On-orbit Recording of Transient Events) Main mission: synaptic lightning observation Viewed Greenland ice (1997-99)  1.9 MILLION km 3  38 days Log-periodic antennas N. Lehtinen et al., PRD 69, 013008 (2004)

33. Askaryan effect: confirmation in sand Experiment at SLAC with beams of photons And 10 10 e-/bunch: effective shower energies 0.06-1.10 10 19 eV 1 Jy = 10 -26 W/m 2 /Hz Angular spread Z 0 ~ Δ c ~ λ /L=1/L ν D. Saltzberg et al PRL 86 (2001) 2802

34. Shower Length 3 simple models  EM (w/ LPM) Length ~ E 1/3 (Alvarez-Muniz & Zas) 1 km at 10 22 eV  Hadronic Length ~ ln(E)  Hybrid Initially EM, but  --> hadrons  400 m at 10 22 eV Purely EM Purely Hadronic Dotted - hybrid e Energy (eV) NOTE Δθ c ≈1/(ℓν )