Post on 20-Jan-2016
M. Leuthold
RADAR Detection of Extensive Air Showers
RADAR Detection of Extensive Air Showers
Nils ScharfIII. Physikalisches Institut ABad Honnef 31.08.2007
Nils ScharfIII. Physikalisches Institut ABad Honnef 31.08.2007
RADAR Detection of EAS 2
Outline
Cosmic Rays and the Auger Observatory RADAR Principles Test Setup First Results Conclusion
RADAR Detection of EAS 3
flu
x(m
²sr
s G
eV)
-1
energy (eV)
direct measurements
KASCADE Grande
AUGER
1 particle per m2 • sec
Knee
1 particle per m2 • year
Ankle
1 particle per km2 •century
Open questions: Composition Origin Propagation
of UHECR
Measure Extensive Air Showers generated by cosmic rays
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
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Detection MethodsDetection Methods
Surface detector Water Cherenkov
detector Samples secondary
particles on ground level
Nearly 100 % duty cycle
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
Fluorescence detector Measures
fluorescence light Samples shower
development Very sensitive, works
only in moonless nights -> 15 % duty cycle
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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
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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
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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 methodLow budget and low maintenance
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Test Setup - Airplanes
Use local transmitter (i.e. TV station) Radio waves reflected on moving
airplanes -> Doppler shift Monitor original and Doppler shifted signal
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Power Supply forPreamplifier and ReceiverSound card
96 kHz16bit sampling
To antenna
Preamplifier
DAQ
Receiver
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144 MHz
ReceiverBandwidth
freq
freq
amp
amp
Demodulation
Receiver frequency 144 MHzReceiver bandwidth 3 kHzRadio waves with frequencies from144.000 MHz to 144.003 MHzreceived
OutputSound waves withfrequenciesfrom 0 Hz to 3000 Hz
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RADAR Detection of EAS 14
Meteor scatter
MeteorIonization Column
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Comparison EAS – Meteors
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
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)
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Transmitter site in southern Norway
Frequency 144 478 000 HzPower 120 WContinuous transmissionDistance 810 km
Matching antenna and receiver for beacon frequency
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First Results - Meteor scatter
Receiver Bandwidth
Local transmitter
Expected MS signals in thisrange
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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
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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
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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