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RADAR Detection of Extensive Air Showers

RADAR Detection of Extensive Air Showers. Nils Scharf III. Physikalisches Institut A Bad Honnef 31.08.2007. Outline. Cosmic Rays and the Auger Observatory RADAR Principles Test Setup First Results Conclusion. Cosmic Rays. Open questions: Composition Origin Propagation of UHECR

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RADAR Detection of Extensive Air Showers

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  1. RADAR Detection of Extensive Air Showers Nils Scharf III. Physikalisches Institut A Bad Honnef 31.08.2007

  2. Outline • Cosmic Rays and the Auger Observatory • RADAR Principles • Test Setup • First Results • Conclusion RADAR Detection of EAS

  3. Cosmic Rays • Open questions: • Composition • Origin • Propagation of UHECR Measure Extensive Air Showers generated by cosmic rays RADAR Detection of EAS

  4. The Auger Observatory 1480 deployed 1400 filled 1364 taking data 082407 ~ 85% All 4 fluorescence buildings complete, each with 6 telescopes AIM: 1600 tanks RADAR Detection of EAS

  5. Surface detector Water Cherenkov detector Samples secondary particles on ground level Nearly 100 % duty cycle Fluorescence detector Measures fluorescence light Samples shower development Very sensitive, works only in moonless nights -> 15 % duty cycle Detection Methods RADAR Detection of EAS

  6. RADAR • Radio Detecting and Ranging • Possible sources for reflection / scattering: • Metallic objects • Airplane monitoring, Car velocity measurements • Regions of high ion density • Lightning RADAR • Atmospheric Probing (Ionized regions in the Atmosphere) • Ionization trails of Meteors • Used as long range communication channel (commercial and by radio amateurs) • Used for meteor science RADAR Detection of EAS

  7. Monostatic: • Transmitter and receiver close to each other (ideal same antenna) • Area around transmitter is monitored RADAR Detection of EAS

  8. Bistatic / Forward Scatter • Great distance between transmitter and receiver • Area between transmitter and receiver is monitored • Use of existing transmitters possible RADAR Detection of EAS

  9. Properties of RADAR for EAS • Large monitored volume (several km3) • Nearly 100 % duty cycle • Active scanning of shower • Monitoring longitudinal shower development • Detection of horizontal showers • Relatively simple detection method • Low budget and low maintenance RADAR Detection of EAS

  10. Test Setup - Airplanes • Use local transmitter (i.e. TV station) • Radio waves reflected on moving airplanes -> Doppler shift • Monitor original and Doppler shifted signal RADAR Detection of EAS

  11. To antenna Power Supply for Preamplifier and Receiver Sound card 96 kHz 16bit sampling Preamplifier Receiver DAQ RADAR Detection of EAS

  12. Demodulation Receiver frequency 144 MHz Receiver bandwidth 3 kHz Radio waves with frequencies from 144.000 MHz to 144.003 MHz received amp Receiver Bandwidth freq 144 MHz amp Output Sound waves with frequencies from 0 Hz to 3000 Hz freq RADAR Detection of EAS

  13. RADAR Detection of EAS

  14. Meteor scatter Ionization Column Meteor RADAR Detection of EAS

  15. Meteors Velocity: ~ 70 km/s Altitude: 80 km to 120 km Energy: ~ 0.1 J Ionization column radius: ~ 10 m Signal duration: 10 ms – 5 s EAS Velocity: nearly c Altitude: 0 km to 20 km Energy: 0.1 J (1018 eV) Ionization column radius: ~ 10 m Signal duration: 20 µs – 20 ms Comparison EAS – Meteors RADAR Detection of EAS

  16. Test Setup for Meteor scatter • Needed: • Transmitter with continuous transmission / high pulse rate below radio horizon of receiver ( distance greater than 500 km) • No local transmitter in used frequency range (noise reduction) RADAR Detection of EAS

  17. Transmitter site in southern Norway • Frequency 144 478 000 Hz • Power 120 W • Continuous transmission • Distance 810 km • Matching antenna and receiver for beacon frequency RADAR Detection of EAS

  18. First Results - Meteor scatter Receiver Bandwidth Local transmitter Expected MS signals in this range RADAR Detection of EAS

  19. RADAR Detection of EAS

  20. RADAR Detection of EAS

  21. First Results - Sound Just 3 examples: different signal types, sometimes only distinguishable by listening to them RADAR Detection of EAS

  22. Results Meteor scatter signals with durations between 0.01 s and 3.5 s found • Hourly rate between 10 and 20 (higher with active meteor shower) • Simple setup working RADAR Detection of EAS

  23. Outlook • Measurements in coincidence with existing shower detectors • Upgrade hardware (higher sampling rate) to detect expected very short EAS signals Antenna Array RADAR Detection of EAS

  24. Conclusion • RADAR is possible new detection method for EAS -> additional information on shower development • Detection of meteor scatter with simple setup established • Several groups are working on EAS detection by RADAR RADAR Detection of EAS

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