Hartmut Gemmeke on behalf of LOPES...

Forschungszentrum Karlsruhein der Helmholtz-Gemeinschaft

Hybrid Detection of UHCRs

Radio detection techniques for cosmic raysHartmut Gemmeke on behalf of LOPES Collaboration

MotivationWhat is the physicsbehind itLearning by simulationLearning by doingLOFAR, LOPES,CODALEMAFuture for radio atAuger

Super-Hybrid Detection of UHECRs


08.08.2006 Hartmut Gemmeke, Hanoi06 2

Motivation:Advantages of radio detection of UHECRs

Assuming UHECRs emit radio signals f = 25 - 80 MHz

• Antennas are cheap detectors, easy to deploy

• Duty cycle 24 hours/day

• Practical no attenuation in air

– Bolometric measurement (integral of EM-signal over shower evolution)

• Also useable for neutrino induced showers

What is the physics behind it?



Askaryan-effectSoviet Phys. JETP 14(1962)441

Cerenkov emission for neutrinos orUHECR induced showers in ice,salt, lunar regolith, sand

Reason: e- charge excess in ν or CRinduced shower

Proof of effect in sand:

D. Saltzberg et al. at SLAC,2005 arXiv:hep-ex/0011001

No theoretical prediction in air

Growing number of experiments planto use this effect:

RICE, GLUE, ANITA, SalSA, LOFAR,Westerbork (E > 1021eV)



Geosynchrotron effect of Cosmic rays in airH.R. Allan started R&D on radio-emission of UHECRs

e- and e+

accelerated on acircle by magneticfield of the earth

⇒ synchrotron radiationin forward direction

1965 Allan



Simulation of Radio Emission from Cosmic Rayscoherent geo-synchrotron emission• history of simulation

– 2003: analytical calculationsRevisited by Falcke&GorhamAstropart.Phys. 19(2003)477⇒coherent geosynchrotron

emission

– 2005: Monte Carlo simulationsbased on parameterized airshowers

– 2006: full Monte Carlo simulationsbased on CORSIKA byhistogramming(Tim Huege FZK-IK)



Simulation: Scaling with Epp(vertical shower)

• Nearly linearscaling

|EEW| ∝ Epp-> EEW ∝ Epp

2

coherent effect

• Radio isbolometric:atmosphere forh < 8 kmtransparent

• Flattening withincreasingdistance

T.Huege, Thesis



Simulation: lateral profilesflattening withincreasing zenithangle

approx. exponentialscaling

R0 = 100 ... 800 m

⇒ Inclined showerscan be seen at largedistances

f = 10 MHzE =1017 eV

Huege & Falcke (2005)



Comparison of parametrized and histogramming MC

• arrival times: spectra get somewhat flatter • spectra steeper athigher distances• low frequenciesbetter for large gridspacings

⇒ Effect ofcomplete MonteCarlo simulation

(vertical shower, 1017 eV)

T. Huege, to be published



Experiments: LOw Frequency ARray LOFAR

• ~10,000 antennas• grouped in ~100 stations with 100 antennas (10-

90 MHz and 110-240 MHz) each– remote stations out to 2-3 hundred kilometers– connected by high-speed internet

• applications:– Cosmology,– bursting universe,– Cosmic Rays & Neutrinos above 1018 eV

• 1st station operational 2006/7

• 2003 Netherland-German Collaboration LOPES =LOFAR PrototypE Station at Karlsruhe

See talk of S. Lafebre in PS1



Test bed for LOPES is KASCADE-Grande

KASCADE

KASCADE + red dots ⇒ KASCADE Grande



RFI Filtering LOPEStime frequency domain

t [µs]

t [µs] after filtering

frequency MHz]

Fiel

d st

reng

th [µ

V/m

/MH

z]Fi

eld

stre

ngth

[µV

/m/M

Hz]

Cal

Pow

er [W

att/B

in]

• Unfiltered data

• Fourier transformation and filter

• Filtered data

⇒ Correlation appears

A.Horneffer 2006, Thesis



KASCADE-Grande Triggered Pulse DetectionElectric field for each

dipole after correcting forinstrumental and geometric

delays.

Block-averaged, radioemission as a function oftime after beam-forming

(Correlation analysis)

Nature 2005 A.Horneffer 2006, Thesis



Calibration of CR Radio Signal with LOPES

B-field

UHECR particle energy

Nature 435, 313 (2005)

A.Horneffer 2006, Thesis

1. Proof of geo-synchrotron effect

2. Threshold at Karlsruhe 6*1016 eV

3. Radio signal is a good scale for energy

4. Emission is coherent: m ≈ 2.0

Dependence on geomagnetic angle



KASCADE Grande Events: Radial Distribution

Apel et al. – LOPES collaboration Astrop.Phys. (2006) submitted

Radio signal scales withcore distance:εν ∼ exp (-R)



Reconstruction of KASCADE-Grande eventswithout LOPES

Improvement in precision ofdirection and core position!?

with LOPESOptimized correlation

Correlation

Gauss-fit

Grande only:

AZ = 302.2°

ZE = 41.6°

XC = -142.9 m

YC = 40.3 m

Radio signal = 0.8

Grande + LOPES:

AZ = 301.6°

ZE = 41.0°

XC = -137.9 m

YC = 30.3 m

Radio signal = 2.8 !!!

0

0.

2

0.4

0.6

0

.80

1

2

-2.2 -2.1 -2.0 -1.9 -1.8 -1.7t [µs]

-2.2 -2.1 -2.0 -1.9 -1.8 -1.7t [µs]

X-co

r [V/

m/M

Hz]

X-

cor [

V/m

/MH

z]

Red points



Influence of thunderstorm on radio signals

• For E > 10 kV/m force by E-fielddominates B-field:

– Fair weather: E ≈ 100 V/m

– Thunderstorms: E ≈ 100 kV/m

• Select thunderstorm periods frommeteorological data:

⇒Clear radio excess duringthunder storms

⇒B-field effect dominates undernormal conditions

⇒> 90% duty cycle possible (KA)Buitink et al. (LOPES coll.) 2005 & 2006 in prep.

Thunderstorm events

control sample



CODALEMA

N

S E

W

Antennas

Particle detectors

Acquisition room

87 m

1.5 m1.5 m

1.5 m1.5 m

PM PM underunder coppercopper housinghousing

Plastic Plastic scintillatorscintillator

Works and measures real UHECR -but has not a KASCADE-experimentnearbyDallier: Arena2005, Zeuthenhttp://www-zeuthen.desy.de/arena

Ardouin et al., astro-ph/0510170

per event lateralprofiles fit wellwith exponentialR0 ~ 100 to 300 m



Future of Radio ?Considered antennas

- V-dipole or Tri-pole (LOFAR)- dipole (CODALEMA)- Logarithmic periodic dipole

antenna (LOPES*)



Analog RF Front End

envelope

radiofrequency1 Vpp

3.3V (22mW/Channel)

Crossed LPDA

CH 2

-BIAS-T

20 dB NF1.8dB± 0.4 V

RG214100 m

BIAS-T

LNASupply

40 MHz 8thorder

80 MHz 8thorder ± 0.4 V 20 dB 20 dB

40 MHz 8thorder

80 MHz 8thorder

Rectifier

3.3 V, 65 mW/Channel50 Ω

50 Ω

ADCs

band-pass filter

Simple envelope trigger(quadratic sum of bothpolarizations)

10ns Pulse

RF-bandpass pulseresponse

Full-wave rectifierfast, only few ripples



Why driving the trigger with rectified RF?

The rectifier is a squaring device: )()()()()()( !!! jSjSjRtststr "=#$=

multiplication (time domain) → Convolution (frequency domain)

f f

f f

CW Carrier DC Signal

Carrier withModulation

DC Signal + lowfrequency

Pulsspectrum

wideband trian-gular spectrum

rect.rect.rect.Rectifier output: Man made RFI turns into DC or low frequency and may be

separated from pulse spectrum by high-pass filtering

s(t) r(t)( )2

f f



Man made RFI shifted to DCand low frequency range

Baseband spectrum at rectifier output



humanmadeInterferencefrom thehorizon

Pulses from the horizon (interference sources)have a delay of: ΔT ≥ h / cproblems: if source of interference is inside or near to the triangle !!

for curvature of pancake -> we need > 3 antennas

Pulses with higher elevation θZenith < 80° (e.g. from air showers)reach the antennas more simultaneously: 0 < ΔT < h/c

h

a

Self trigger: Coincidence of min. 3 antennas

θzenith = 30°

θzenith = 60°

θzenith = 90°

pointing informationin plane wave appr.

tES

tNS

scale for a=65m

N

S

E

Δθ-sensitivity



ready

17

19

30

+ triangle at IPE site, 250 m

radio-detector

LOPES*

in FZK

KASCADE



Radio test at Auger-South1. 2006/07: tests

antenna performance (4 types), noise immunity, trigger, coincidences with surface detector of

Auger

2. 2007: review3. 2007-8: if review positive

build an engineering array on 10 km2

4. 2009: review and decide on an add-up to Auger South &

North

test station atballoonlaunchingstation of Auger

possiblegeometry

in cells of 7antennas

1.5 km



Conclusions1. Angular Resolution: discovery of point sources with Radio: Δθ < 1°

– with more antennas a resolution of ≤ 0.2° seems feasible

2. Bolometric Measurement of Energy correlated with geomagneticangle

3. Emission is coherent4. Thunderstorms have an effect, but can be discriminated⇒ complementary information to Fluorescence and Surface detectors• Polarization, Composition?: working on itInstallation of several antennas in Argentina 2006

But much has to be done before you can apply it to Auger-North⇒ Auger-South is the necessary test-field for the future of radio



THANKS

Radio on the highway to Auger-North?



LOPES CollaborationW.D. Apela, T. Aschb, A.F. Badeaa, L. Bährenc, K. Bekka, A. Bercucid, M. Bertainae, P.L.Biermannf, J. Blümera,g, H. Bozdoga, I.M. Brancusd, S. Buitinkh, M. Brüggemanni, P. Buchholzi, H.Butcherc, A. Chiavassae, F. Cossavellag, K. Daumillera, F. Di Pierroe, P. Dolla, R. Engela, H.Falckec,f,h, H. Gemmekeb, P.L. Ghiaj, R. Glasstetterk, C. Grupeni, A. Haungsa, D. Hecka, J.R.Hörandelg, A. Hornefferh, T. Huegea, K.H. Kampertk, Y. Kolotaevi, O. Krömerb, J. Kuijpersh, S.Lafebreh, H.J. Mathesa, H.J. Mayera, C. Meurera, J. Milkea, B. Mitricad, C. Morelloj, G. Navarrae,S. Nehlsa, A. Niglh, R. Obenlanda, J. Oehlschlägera, S. Ostapchenkoa, S. Overi, M. Petcud, J.Petrovich, T. Pieroga, S. Plewniaa, H. Rebela, A. Rissel, M. Rotha, H. Schielera, O. Simad, K.Singhh, M. Stümpertg, G. Tomad, G.C. Trincheroj, H. Ulricha, J. van Burena, W. Walkowiaki, A.Weindla, J. Wochelea, J. Zabierowskil, J.A. Zensusf, D. Zimmermanni

a Institut für Kernphysik, Forschungszentrum Karlsruhe, 76021 Karlsruhe, Germanyb Institut für Prozessdatenverarbeitung und Elektronik, Forschungszentrum Karlsruhe, 76021 Karlsruhe, Germanyc ASTRON, 7990AA Dwingeloo, The Netherlandsd National Institute of Physics and Nuclear Engineering, 7690 Bucharest, Romaniae Dipartimento di Fisica Generale dell’ Universita, 10125 Torino, Italyf Max-Planck-Institut für Radioastronomie, 53121 Bonn, Germanyg Institut für Experimentelle Kernphysik, Universität Karlsruhe, 76021 Karlsruhe, Germanyh Dpt. Astrophysics, Radboud University, 6525 ED Nijmegen, The Netherlandsi Fachbereich Physik, Universität Siegen, 57072 Siegen, Germanyj Instituto di Fisica del lo Spazio Interplanetario, INAF, 10133 Torino, Italyk Fachbereich C − Physik, Universität Wuppertal, 42097 Wuppertal, Germanyl Soltan Institute for Nuclear Studies, 90950 Lodz, Poland

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