overview on radio detection of air showers · yachay, ecuador [email protected] institut für...

KIT – The Research University in the Helmholtz Association

Karlsruhe Institute of Technology (KIT), Institut für Kernphysik, Karlsruhe, Germany

www.kit.edu

Frank G. Schröder

Overview on Radio Detection of Air Showers

2 08 December 2016 Radio Detection of Cosmic RaysYachay, Ecuador

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Institut für Kernphysik

Accurate measurement of energy and Xmax around the clock

Radio

Advantages of radio technique


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arXiv:

1607.08781


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Emission mechanisms

Askaryan effect ~ 10%geomagnetic effect ~ 90%


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Conical radio emission with asymmetric footprint

CoREAS simulations By T. Huege et al., ARENA2012

shower

inclination:

q = 45°

43 – 74 MHz


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3.4 – 4.2 GHz

Geomagnetic emission at Cherenkov ring

GHz emission beamed into narrow cone

CROME @ KIT


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Do simulations describe reality?

CoREAS (+ other codes) reproduce measured amplitudes within ~20% uncertainty

Tunka-Rex Coll.,Nucl. Instr. Meth. A 802 (2015) 89

LOPES Coll.,Astropart. Phys. 75 (2016) 72

(CoREAS)

(CoREAS)


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1st Answer: How well do we understand the radio emission?

To a level of 10-20%

better than for muon content of air-showers

similarly good as fluorescence detection, but various systematics are not yet

extensively studied

Open questions for becoming even better

What is the impact of atmospheric humidity?

Is the proportionality with geomagnetic field exact?

How exactly behaves the emission for near-horizontal showers?


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Jelley et al Nature 1965,

R. A. Porter MSc Thesis 1967

Experiments: First Detection

Qualitative features discovered 50 years

ago, but measurements lacking accuracy


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Location of selected experiments and geomagnetic field


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1 km

CODALEMA3

(57)

Compilation by A. Zilles

Designs of modern radio arrays(mostly externally triggered)


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30 dipole antennas

40 – 80 MHz, east-west / north-south

Trigger by KASCADE

LOPES setup (map of 2009)


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Detectors: antennas

Many working solutions with only slight differences in

threshold (typical 1017 eV) and frequency band (typical 30-80 MHz)

accuracy (systematic uncertainties, e.g., due to ground conditions)

SALLA at

Tunka-Rex LPDA at Augerinverted v-dipole at LOPESButterfly at

CODALEMA


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Direction

example: LOPES

Energy

example: AERA and others

Shower maximum

example: LOFAR + Tunka-Rex

Reconstruction of shower parameters


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Cross-correlation of traces after time shift according to arrival direction

Direction precision ~ 0.5° (by comparing LOPES to KASCADE)

Interferometric beamforming at LOPES

LOPES Coll., Astroparticle Physics 50-52 (2013) 76 + Nature 435 (2005) 313

cross-

correlation

total power


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750 m

Auger Engineering Radio Array

153 autonomous stations on 17 km²


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750 m

LPDA




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Butterfly

750 m

LPDA




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Energy reconstruction by AERA

Total energy in radio signal scales quadratically with electro-mag. shower energy

slope = 1.98 ± 0.04

16 MeV

energy

resolution:

17%

Pierre Auger Coll.,

PRL 116 (2016) 241101


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Moscow experiment:

Vernov et al. (1968)

LOPES Coll., AIP Conf. Proc.

1535 (2013) 78

Tunka-Rex,JCAP 01 (2016) 052

Similar energy precision by other experiments

+ several other

experiments


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Several 100 antennas on several 100 m²

Low band: 10-90 MHz

High band: 110-190 MHz

LOFAR superterp, the Netherlands


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High precision by intensive simulations

Pick the one of many simulations describing data best

very high precision < 20 g/cm²

provided no unknown systematics: competitive with fluorescence

LOFAR Coll, PRD 90 (2014) 082003


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Bildquelle: Wikimedia

Irkutsk


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Layout of Tunka-Rex

Array layout

200 m spacing in 1 km² inner area

Fully analyzed: Oct 2012 – Apr 2014

Year Stations Trigger

2012 19 Tunka-133

2013 25 Tunka-133

2014 timing problem

2015 44 Tunka-133

+ Grande

2016 63since Nov.

Tunka-133

+ Grande


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One of several methods: slope of lateral distribution

Shower maximum: proof by Tunka-Rex

Tunka-Rex Coll.,

JCAP 01 (2016) 052

precision:

40 g/cm²


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CoREAS takes situation of each experiment into account

Alternative way: Ratio of measured to simulated amplitude


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Tunka-Rex + LOPES Colls.,

PLB 763 (2016) 179

Comparing

energy scales

via radio


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2nd Answer: What is the accuracy for shower observables?

Accuracy competitive to fluorescence technique

direction < 0.5°

energy < 20% (precision + scale)

Xmax < 20 g/cm² (with high antenna density)

Next steps currently under investigation

Can we reach an energy accuracy of 5-10%?

Can we achieve 20 g/cm² Xmax resolution with sparse arrays?

Can we exploit composition sensitivity beyond Xmax?


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3rd Answer: What ideas and plans are there beyond Xmax?

Neutrino search above 1016 eV

radio arrays in and on ice – ARA, ARIANNA

Ultimate precision around 1017 eV

the low-frequency core of the Square Kilometer Array (SKA)

Highest apertures for 1020 eV

huge arrays for inclined showers (GRAND), satellites, the Moon

cosmic rays and neutrinos


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ARA Collaboration ARIANNA Collaboration

Neutrino-induced showers in ice


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S.W. Barwick,

PoS (ICRC2015) 027


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T. Huege et al.,

ICRC 2015, Den Haag

antenna stations

particle detectors

The Square Kilometer Array: ultra high precision

Phase 1: ~ 60,000 antennas on ½ km²

Scintillator array planned for E > 1016 eV


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P. Gorham, et al.

(ANITA Coll.)

Cosmic-Ray detection by ANITA


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Enables large-scale, sparse antenna arrays for reasonable costs

Huge footprint for inclined showers

vertical

50°

75°

E = 1018 eV

CoREAS simulationAuger measurement

E = 3.6.1018 eV, q = 75.7°

Pierre Auger Collaboration, PoS (ICRC2015) 615


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Composition sensitivity for inclined showers

Only radio emission + muons survive for inclined showers

Complementary information on shower primary particle type


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more in arXiv: 1607.08781

Conclusion

Significant progress in last years

radio is on the way to a standard technique

emission understood to at least 10 - 20 % accuracy

Competitive accuracy for air shower parameters

direction < 0.5°

energy < 20% (precision + scale)

Xmax < 20 g/cm² (with high antenna density)

Radio ideal for particle-detector arrays at E >1017 eV

enhancement of accuracy for cosmic rays

neutrino search


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Backup


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Scintillation counters

Inside underground

Muon detector

Scintillation counters

Inside surface

particle detectorEntrance to

muon detector

Electronic

box

Tunka-133 and Tunka-Grande at TAIGA

ECRS 2014

Tunka Coll.

Cosmic Rays

Tunka-133

Tunka-Grande

Tunka-Rex

Gamma Rays

HiSCORE

IACT

Muon detectors

as veto


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30-80 MHz

Using data acquisition of

Tunka-133 / Tunka-Grande

Tunka-Rex signal chain


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Digitally shift all traces

according to arrival time of

hyperbolic wavefront

Cross-correlation of antennas

Interferometric beamforming at LOPES

LOPES Coll.,


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Cherenkov ring (predicted by Allan 1971)


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Relative strength of Askaryan effect


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Hyperbolic radio wavefront

Hyperbolic shape seen by LOPES and LOFAR

Slight east-west asymmetry not yet confirmed

LOPES Coll., JCAP 09 (2014) 025

LOFAR measurementAstropp. 61 (2015) 22

CoREAS for LOPES

r1°- 2°


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Efficiency of Tunka-Rex standard reconstruction


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Amplitude calibration

Commercial reference

source also used by

LOPES and LOFAR

Common amplitude scale

overview on radio detection of air showers · yachay, ecuador [email protected] institut für...

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