D' Ardouin SUBATECH

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Characteristics of Radioelectric fields from
air showers induced by UHECR measured by
CODALEMA

• D. Ardouin - SUBATECH
• for the CODALEMA collaboration
• SUBATECH, Nantes
• Obs. de Paris-Meudon
• Obs. de Nançay
• LAL Orsay
• ESEO Angers
• LPSC Grenoble
• LPCE OrleansLAOB Besançon
• (FRANCE)

ECRS2006
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CODALEMACOsmic ray Detection Array with
Logarithmic ElectroMagnetic Antennas
11 antennas, band-pass filtered (24-82 MHz) 608m
East-West-, 120 m SW-SE lines 4-fold
coinc.trigger from particle-detectors
ECRS2006
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Radio-waves arrival times correlate with particle
front times identification of CR
ECRS2006
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Field topologies
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Field topologies field profiles
Characteristic shapes appear as genuine radio
signatures of EAS and enable a stand-alone
mode of characterization with an antenna array
ECRS2006
4 EAS typical events detected along the E-W
line
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In the ground coordinate system
Shower impact determination from EAS field
distributions
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1 antenna
Background
MHz
ECRS2006
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Specificity the large azimuthal acceptance
allows investigation of inclined showers
Under way detailed physical correlations with
impact parameter,energy, nature of
primaries,with higher statistics and a completed
set-up
ECRS2006
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COMPLEMENTS
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Skymap of radio coincidences ( ? 3 antennas)
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Reconstructed arrival directions for EAS events
with antenna multiplicities ? 4
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Cosmic ray counting rate vs zenith angle
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Antenna acceptance/ particle acceptance for true
EAS events vs zenith angle
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d0 width distributionfor 64 events M? 4
Mean extension of the field Indication for
designs of large arrays
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• NEW Trigger 13 particle detectors
• counting rate 1 evt / 7 min
• energy threshold 1x1016eV
• 16 antennas new dipole array on the North
  South axis

ECRS2006
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A dedicated LNA(ASIC)
Didier CHARRIER,
FWHM
Aluminium dipole antenna
Preamplifier ASIC

• Constant directivity, No side lobes from 100kHz
  to 70MHz
• H-plane half beamwidth120
• E-plane half beamwidth90

High sensitivity and wide bandwidth
Short Waves
FM band 88-108MHz
10dB
15MHz
sky noise, ?6dB_at_75MHz
Dipole Preamplifier noise
Analyzer noise
Spectrum measured from 1MHz to 150MHz at Nançay
10th PISA meeting
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Present developments New active dipole antenna
no side lobes from 100 KHz to 70 MHz,
dipole-Decametric array interference pattern with
Cas.A sourceVery good astronomical performances
on a wide band
ECRS2006
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CODALEMA

• NEW Trigger 5 particle detectors (13 soon)
• counting rate 1 evt / 7 min
• energy threshold 1x1016eV
• New dipole array on the North South axis

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Transient detection and datation
Datation t
Threshold n.s
Noise s
Triggering time tagging
Filtered band
Full band
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