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

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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

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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

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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

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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