The NuMoon experiment: first results

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The NuMoon experiment first results

• Stijn Buitink
• for the NuMoon collaboration
• Radboud University Nijmegen
• 20th Rencontres de Blois, 2008 May 19

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The Cosmic Ray Spectrum

• What is the origin?
• Acceleration sites?
• Top down models?
• Search for sources
• ? highest energies

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Propagation of cosmic rays
Cronin 2004
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GZK Cutoff
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Search for UHE CRs and neutrinos
Flux above 1020 eV 1 /km2/sr/century
Pierre Auger Observatory 3000 km2
IceCube 1 km3
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Principle of the measurement
Cosmic ray
Detection Westerbork antennas
107 km2
100MHz Radio waves
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Askaryan effect Coherent Cherenkov emission

• Leading cloud of electrons, v ? c
• Typical size of order 10cm
• Coherent Cerenkov for ? ? 2-5 GHz
• cos ?c 1/n , ?c56o for 8 shower
  length
• Length of shower, L ? few m
• Important for angular spreading

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Neutrinos 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

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Surface roughness
Small scale roughness scatters radiation Large
scale roughness disfavours CR detection
James Protheroe 2008
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Spreading around Cerenkov-cone
Lunar regolith n 1.8
GHz
GHz
Scholten et al. 2006
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Reflection

• Spreading is diminishing internal reflection

3 GHz
100 MHz
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Position on Moon
Calculations for Ecr4 1021 eV Detection
treshold 500 Jy for 20 MHz bandwidth

• With decreasing ?
• - increasing area
• - increasing probability
• ? over surface Moon
• D ? ?-3

Partial Detection probability
Normalized distance from center
Scholten et al. 2006
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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 JPLs Goldstone, Calif. Tracking
Station _at_ 2.2 GHz
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James Protheroe, 2008
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NuMoon Experiment _at_ 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
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NuMoon Experiment _at_ WSRT
Use Westerbork radio observatory
4 frequencies
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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

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• Simulated pulse dispersed in ionosphere
• (TEC 10)

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raw data
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dedispersion
Trigger 4s pulse in all four frequency bands
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(No Transcript)
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Trigger Power Spectrum
Effect successive steps in analysis
Gaussian noise
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Prelimenary Results

• Analysis of
• 10 h 40 min data

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Future Lofar
Lofar High Band antennas 120-240 MHz 77
stations 2x2 km core outlying stations
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Lofar neutrino sensitivity
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Lofar UHE CR sensitivity
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Lunaska

• Australia Telescope Compact Array
• Undergoing upgrade
• 2 GHz bandwidth 5 antennas

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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
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Future sensitivity
LOFAR
James Protheroe, 2008
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Conclusions

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

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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)
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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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Shower Length

• 3 simple models
• EM (w/ LPM)
• Length E1/3
• (Alvarez-Muniz Zas)
• 1 km at 1022 eV
• Hadronic
• Length ln(E)
• Hybrid
• Initially EM, but
• g --gt hadrons
• 400 m at 1022 eV

Purely EM Purely Hadronic Dotted - hybrid
ne Energy (eV)
NOTE ??c 1/(l? )