hartmut gemmeke on behalf of lopes...
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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
Forschungszentrum Karlsruhein der Helmholtz-Gemeinschaft
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?
Forschungszentrum Karlsruhein der Helmholtz-Gemeinschaft
08.08.2006 Hartmut Gemmeke, Hanoi06 3
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)
Forschungszentrum Karlsruhein der Helmholtz-Gemeinschaft
08.08.2006 Hartmut Gemmeke, Hanoi06 4
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
Forschungszentrum Karlsruhein der Helmholtz-Gemeinschaft
08.08.2006 Hartmut Gemmeke, Hanoi06 5
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)
Forschungszentrum Karlsruhein der Helmholtz-Gemeinschaft
08.08.2006 Hartmut Gemmeke, Hanoi06 6
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
Forschungszentrum Karlsruhein der Helmholtz-Gemeinschaft
08.08.2006 Hartmut Gemmeke, Hanoi06 7
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)
Forschungszentrum Karlsruhein der Helmholtz-Gemeinschaft
08.08.2006 Hartmut Gemmeke, Hanoi06 8
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
Forschungszentrum Karlsruhein der Helmholtz-Gemeinschaft
08.08.2006 Hartmut Gemmeke, Hanoi06 9
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
Forschungszentrum Karlsruhein der Helmholtz-Gemeinschaft
08.08.2006 Hartmut Gemmeke, Hanoi06 10
Test bed for LOPES is KASCADE-Grande
KASCADE
KASCADE + red dots ⇒ KASCADE Grande
Forschungszentrum Karlsruhein der Helmholtz-Gemeinschaft
08.08.2006 Hartmut Gemmeke, Hanoi06 11
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
Forschungszentrum Karlsruhein der Helmholtz-Gemeinschaft
08.08.2006 Hartmut Gemmeke, Hanoi06 12
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
Forschungszentrum Karlsruhein der Helmholtz-Gemeinschaft
08.08.2006 Hartmut Gemmeke, Hanoi06 13
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
Forschungszentrum Karlsruhein der Helmholtz-Gemeinschaft
08.08.2006 Hartmut Gemmeke, Hanoi06 14
KASCADE Grande Events: Radial Distribution
Apel et al. – LOPES collaboration Astrop.Phys. (2006) submitted
Radio signal scales withcore distance:εν ∼ exp (-R)
Forschungszentrum Karlsruhein der Helmholtz-Gemeinschaft
08.08.2006 Hartmut Gemmeke, Hanoi06 15
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
Forschungszentrum Karlsruhein der Helmholtz-Gemeinschaft
08.08.2006 Hartmut Gemmeke, Hanoi06 16
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
Forschungszentrum Karlsruhein der Helmholtz-Gemeinschaft
08.08.2006 Hartmut Gemmeke, Hanoi06 17
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
Forschungszentrum Karlsruhein der Helmholtz-Gemeinschaft
08.08.2006 Hartmut Gemmeke, Hanoi06 18
Future of Radio ?Considered antennas
- V-dipole or Tri-pole (LOFAR)- dipole (CODALEMA)- Logarithmic periodic dipole
antenna (LOPES*)
Forschungszentrum Karlsruhein der Helmholtz-Gemeinschaft
08.08.2006 Hartmut Gemmeke, Hanoi06 19
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
Forschungszentrum Karlsruhein der Helmholtz-Gemeinschaft
08.08.2006 Hartmut Gemmeke, Hanoi06 20
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
Forschungszentrum Karlsruhein der Helmholtz-Gemeinschaft
08.08.2006 Hartmut Gemmeke, Hanoi06 21
Man made RFI shifted to DCand low frequency range
Baseband spectrum at rectifier output
Forschungszentrum Karlsruhein der Helmholtz-Gemeinschaft
08.08.2006 Hartmut Gemmeke, Hanoi06 22
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
Forschungszentrum Karlsruhein der Helmholtz-Gemeinschaft
08.08.2006 Hartmut Gemmeke, Hanoi06 23
ready
17
19
30
+ triangle at IPE site, 250 m
radio-detector
LOPES*
in FZK
KASCADE
Forschungszentrum Karlsruhein der Helmholtz-Gemeinschaft
08.08.2006 Hartmut Gemmeke, Hanoi06 24
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
Forschungszentrum Karlsruhein der Helmholtz-Gemeinschaft
08.08.2006 Hartmut Gemmeke, Hanoi06 25
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
Forschungszentrum Karlsruhein der Helmholtz-Gemeinschaft
08.08.2006 Hartmut Gemmeke, Hanoi06 26
THANKS
Radio on the highway to Auger-North?
Forschungszentrum Karlsruhein der Helmholtz-Gemeinschaft
08.08.2006 Hartmut Gemmeke, Hanoi06 27
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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