The Auger Engineering Radio Array

The Auger
Engineering Radio
Array
Anna Nelles
Cosmic Rays
AERA
sources of particles still
unknown
 nature of particles not
known at these energies

Cronin, Gaisser, Swordy 1997
2
Anna Nelles, Schule für Astroteilchenphysik, Universität Erlangen-Nürnberg, 2011
Pierre Auger Observatory
• province of Mendoza, Argentina, 3500 km2
• 5 Fluorescence Detectors (FD)
• fluorescent light from nitrogen molecules (~10% duty cycle)
• 1600 Surface Detector Stations (SD)
• particle content of shower at ground level (~100% duty cycle)
3
Anna Nelles, Schule für Astroteilchenphysik, Universität Erlangen-Nürnberg, 2011
Radio Detection of Cosmic Rays
Geomagnetic
Field
Shower Front
+
+
+
__
__
-
coherent
E-Field
Radio pulses
4
electrons and positrons in
shower emit coherent radiation
 geomagnetic synchrotron
 charge variation
 ...
 frequencies in MHz range
 enables to observe the
shower development
 new method to study
composition of air showers
 about >90% duty cycle

Anna Nelles, Schule für Astroteilchenphysik, Universität Erlangen-Nürnberg, 2011
4.Antennas
5.Electronics
AERA
6.Communications
• Collaboration7.Power
of Groupsharvesting
from:
and EMC
• France, Germany
8.DAQ and the Netherlands
• Colocation with
Augeranalysis
low energy extensions:
9.Risk
• HEAT (FD),
AMIGA (SD)
10.Management
6000
5000
• Three stages:
Jörg R. Hörandel, Radboud University Nijmegen for
• Stage 1
• 24 antennas
train
• Stage 2
station
+ 52 antennas
road
• Stage 3
HEAT
+ 85 antennas
AERA
4000
Auger Engineering Radio Array
3000
p
92
102
124
153
0
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1000
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81
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ine
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58 59 21 22 60 61 62 63 64 65
1000
125
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2000
114
rl
e
w
o
15666
37
67
2000
BATATA
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CRS
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3000
Anna Nelles, Schule für Astroteilchenphysik, Universität Erlangen-Nürnberg, 2011
73
74
75
fence
4000
76
157
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5000
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6000
161
7000
AERA stations
Logarithmic-Periodic Dipole Antenna
Bandwidth 30 - 80 MHz
with Low Noise Amplifier and Filter
GPS Antenna
Solar Panels
Fiber Connection
to Central Station
Electronics Box
Read-Out Electronics
Communication
Batteries
6
Anna Nelles, Schule für Astroteilchenphysik, Universität Erlangen-Nürnberg, 2011
AERA Data taking
On station level:
DAQ in Central Radio Station
Trigger to
DAQ
- dynamic thresholds
- noise thresholds
- trigger on either
polarization
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Read-Out
request
- checking for
coincidences in time
in > 1 station
- study for optimal
time-window
- reduction of data
- Event building
- storage of raw
data for analysis
Anna Nelles, Schule für Astroteilchenphysik, Universität Erlangen-Nürnberg, 2011
y [km]
y [km]
Cosmic Ray Events
15.8
16
15.8
15.6
15.6
15.4
15.4
15.2
15.2
15
14.8
15
-26.6 -26.4 -26.2
-26
-25.8 -25.6 -25.4
14.8
-26.6
-26.4
-26.2
-26
-25.8
-25.6
x [km]

8
Since April 15th:
 self-triggered cosmic ray events
in coincidence with SD

37 events of which 18 at least
3-fold, one with FD
y [km]
x [km]
15.6
15.4
15.2
15
14.8
-26.6
-26.4
Anna Nelles, Schule für Astroteilchenphysik, Universität Erlangen-Nürnberg, 2011
-26.2
-26
-25.8
x [km]
SD
AERA
Events
Cosmic Ray Events
Coincidence
6
Accidental
4
2
0
-15000
Agreement of directions to
within 3 degrees space
angle
9
-10000
-5000
5000
0
tSD - t AERA [ns]
Very clearly defined timing
offset due to trigger
conditions
Anna Nelles, Schule für Astroteilchenphysik, Universität Erlangen-Nürnberg, 2011
Longterm-Performance
every 10 s a
background trace
is recorded
 stations are
running stable
 very little
narrow-band RFI
 electronics
very quiet
 background
spectrum
dominated by
galactic noise

10
Anna Nelles, Schule für Astroteilchenphysik, Universität Erlangen-Nürnberg, 2011
Noise and Transients
non-negligible amount of radio
interference
 five primary sources
 probably human made

at large zenith angles less
interference

will be vetoed
11
will trigger
Anna Nelles, Schule für Astroteilchenphysik, Universität Erlangen-Nürnberg, 2011
Summary and Outlook
• 21 Stations deployed in Argentina
• Stations are operating within Engineering
parameters
• Ongoing effort on suppression of interference and
background monitoring
• Coincidences of radio self-triggered events with SD
observed
first air-showers detected
12
Anna Nelles, Schule für Astroteilchenphysik, Universität Erlangen-Nürnberg, 2011