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14th,July,2017,ICRC2017
Experimentalcalibra/onoftheARAradioneutrinotelescopewithanelectronbeaminice
R.Gaior,A.Ishihara,T.Kuwabara,K.Mase,M.Relich,S.Ueyama,S.YoshidafortheARAcollaboraFon,
M.Fukushima,D.Ikeda,J.N.MaLhews,H.Sagawa,T.Shibata,B.K.ShinandG.B.Thomson
K.Mase 1
14th,July,2017,ICRC2017
■ TheARAcalibra/onwiththeTA-ELS(ARAcalTA)PerformedinJanuary,2015atTAsite,Utah�
Purpose:BeLerunderstandingoftheradioemissionsandthedetectorcalibraFon �
Wemeasured² PolarizaFon² AngulardistribuFon² Coherence
Antenna tower Extendable: 2-12m�
Ice target�
Vpol antenna�Hpol antenna�
40 MeV electron beam line�
TA LINAC �
Bicone ARA antenna
150-850 MHz� LNA + filter (230-430 MHz)�
K.Mase 2
�
14th,July,2017,ICRC2017
■ TALINACMeasured bunch structure ~10 bunches�
2 ns�
2×108 electrons → Enough signal strength
Correlation → Monitor of electron number�
Cover wide range → Coherence�
ü 40MeVelectronbeamü Typicalelectronnumberperbunchtrain:2×108
→30PeVEMshowerü Pulsefrequency:2.86GHz
→pulseinterval:350ps
ü BunchtrainwidthwasopFmizedto~2nsü Beamlateralspread:~4.5cmü Triggersignalavailableü Electronnumbercanbemonitored(~3%)
K.Mase 3
■ Icetargetandtheconfigura/onsl 100 x 30 x 30 cm3 l Easily rotatable structure
l Easily movable on a rail
l Plastic holder for the ice has a hole underneath for the beam
40 MeV electron beam line�
l Main data sets l With ice (30°, 45°, 60°) l No target�
Thermometer �
Dry ice (on side) �1 m�
α=60°�
α=30°�
Cherenkov angle in ice (56°)�
R. Gaior, 1135, ICRC2015 �
14th,July,2017,ICRC2017
observation angle�
40MeVelectrons�
emission angle�
emission angle [deg.]�
ice inclination angle (α)
Ice target�
K.Mase 4
Electrons stop after running 20 cm in ice due to an ionization loss → Wide angle distribution
14th,July,2017,ICRC2017
■ Expectedradioemissionsü Several radio emissions are expected
ü Askaryan radiation ü In ice ü Wide angular distribution due to the short tracks ü Peak at more horizontal direction than the
Cherenkov angle (56°)
ü Transition radiation ü At air/ice boundary ü Peak at Cherenkov angle (56°)
ü Sudden appearance radiation ü When beam appears ü Forward emission (Cherenkov angle is ~1°) ü More in Krijn’s talk on Tuesday
ElectronLightSourcefacility�
20 cm hole�
metal �
ice �
beam pipe�
40MeVelectrons�
Askaryan radiation�
Transition radiation�
Sudden appearance signal�
K.Mase 5
Obs. angle 0° (no target) at 1 m�
Middle point
Endpoints
14th,July,2017,ICRC2017K.Mase 6
■ Simula/on �Bunch structure �
2 ns�
Lateral distribution�
4.5 cm�
ElectronLightSourcefacility�
20 cm hole�
metal �
ice �
beam pipe�
40MeVelectrons�
Emission in ice�
Emission in air�
Electron beam (Geant4)�
E-field calculation�
Ray trace �
Based on the classical EM theory (Lienard-Wiechert potentials)
Middle point method (PRD 81, 123009 (2010))
Endpoints method (PRE84, 056602 (2011))
Thanks to Anne Zilles for sharing her code for the implementation
Including accelerator configurations�
E-field �
tables made�
20 cm�
E-fi
eld
[V/m
]�
14th,July,2017,ICRC2017 �
■ Detectorsimula/on
＋� ＋�
=�
E-field � Antenna response (T-domain)� filter + LNA response�
K.Mase� 7�
2 ns�
R. Gaior, 1135, ICRC2015�
Time [ns]� Time [ns] � Frequency [GHz]�
E-fi
eld
[V/m
]�
Ant
enna
hei
ght [
m]�
Gai
n [d
B]�
Time [s]�
Volta
ge [V
]�
5 ns� 230-430 MHz�
Verify the understanding the emission mechanisms and detector responses, comparing with data�
Obs. angle 0° (no target) at 1 m�
Time [ns]40 60 80 100 120 140
Volta
ge [V
]
-0.3
-0.2
-0.1
0
0.1
0.2
0.3Time [ns]
40 60 80 100 120 140
Volta
ge [V
]
-0.3
-0.2
-0.1
0
0.1
0.2
0.3
■ Comparisonsofwaveformandthefrequencyspectrum
ü Reasonable agreements between data and simulation after correcting the cable attenuation
ü Less Hpol signal → high polarization
ü Some indications of noise
Vpol �
Hpol �
Vpol �
Configuration: Ice 60°, obs. angle: 15°
Simulation Data �
Simulation Data �
Simulation Data
14th,July,2017,ICRC2017K.Mase 8
Groupreview� 9�
■ Cable/connectoraYenua/oncorrec/onFaraday Cup (for the electron charge measurement)�
TA short cables / connectors (~3m, up to 500 MHz)� Long cables (40m, high
frequency adapted)�
TA LINAC �
oscilloscope�
Counting house�40MeVelectrons�
K.Mase�
Long (45 m)
Short (3 m) Short + Long (40 m)�
Original Long (45 m)
Short (3 m)
Short + Long (40 m)�
Charge loss 9.9 %
23.5%
45.7%�
² Found out the TA short cable attenuate signal significantly ² Electron number for data was underestimated by 46% ² The emission power is proportional to the charge square → correction of x2.1 (1.462) ² Original bunch structure turned out to be more narrower
Time [ns]�
Volta
ge [V
]�
Time [ns]40 60 80 100 120 140
Voltag
e [V]
-0.3
-0.2
-0.1
0
0.1
0.2
0.3 Data Simulation�
Time [ns]�
■ Polariza/onPolarization�
Polarization angle�
Data (Ice target) Simulation (Ice target) Data (No target)�
ü All signals shows relatively high vertical polarization
ü Smaller polarization for the no target configuration ü Less polarized signals for the outside of the main
peak → indication of the noise contamination
Icetarget 0.92±0.03
SimulaFon 1.00±0.01
Notarget 0.82±0.03
Highly polarized�
Configuration: Ice 60°, obs. angle 15°, Vpol�Time development of polarization�
Pol
ariz
atio
n�Time [ns]�
Data Simulation�
14th,July,2017,ICRC2017K.Mase 10
Volta
ge [V
]�
(electron number)10
Log7.6 7.8 8 8.2 8.4 8.6
(radi
o en
ergy
[J])
10Lo
g
-11.8
-11.6
-11.4
-11.2
-11
-10.8
-10.6
-10.4
-10.2
Time [ns]0 20 40 60 80 100 120 140 160 180 200
Voltag
e [V]
-0.3
-0.2
-0.1
0
0.1
0.2
0.3
Data Simulation�
Volta
ge [V
]�
Time [ns]�
14th,July,2017,ICRC2017
■ Coherence
Slope index: 1.86 ± 0.01�
ü High coherence, but not full → Possibly due to the noise
ü Similar values for all the configurations (Even Hpol too)�
Data
ü High coherence around the all main pulse ü Noises seem to show the high coherence�
Configuration: Ice 30°, obs. angle 0°, Vpol�Time development of coherence�
Time [ns]�
Slo
pe in
dex�
K.Mase 11
14th,July,2017,ICRC2017
■ Angulardistribu/on
ü Noise were filtered using a time window (±5 ns) with respect to the peak in a waveform
ü Reasonable agreement after applying the noise cut (otherwise the shapes do not agree, data is ~60% higher)�
ElectronLightSource
facility�
ice �
40MeVelectrons�
Observation angle�
Preliminary�
distance corrected, but antenna gain not corrected�
K.Mase 12
θc(30°)� θc(45°)� θc(60°)�
14th,July,2017,ICRC2017
■ Summaryl We have performed an experiment at Utah using the TA-ELS for the better
understanding of radio emissions and the ARA antennas
l Highly polarized and coherent signals were observed
l Radio signals observed from the beam appearance
l More signals observed when using an ice block
l Agreements improved after correcting the cable attenuation
l More detail simulation constructed to take the reflection and refraction into account
l Need to understand the noise a little better
l Like to understand how much Askaryan signals are contained using simulation
K.Mase 13
14th,July,2017,ICRC2017
Backups �
K.Mase 14
14th,July,2017,ICRC2017
2km
² Aimstodetecthighenergyneutrinosabove30PeVusingAskaryanradiaFon
² 37staFons(3staFonsdeployedsofar)² EachstaFonhas4stringsat200mdepth² Eachstringhas2Vpol+2Hpolbroadband
antennas(~200–800MHz)
² Totalsurfacearea~100km2
² ~10IceCube@1EeV�
Astroparticle Physics 35 (2012) 457–477�
■ AskaryanRadioArray(ARA)
K.Mase 15
GroupreviewK.Mase 16
[dBi]�
Angle [deg.]�
Bunch number�
Rat
io�
■ Systema/cuncertain/es
Bunch after cable correction Widest case
Shortest case �
1 ns�
Original Long (45 m)
Short (3 m)
Short + Long (40 m)�
Item Data Simula/on
StaFsFcalerror ±7% ±10%
Stability ±19% -
Antennaresponseuncertainty
-17%+14%
Bunchwidth - -14%+17%
Sum ±20% ±24%
Time [ns]�
1 ns�
17/07/14� 17�
■ Waveformagreements(notarget)
0 m� 3.5 m�
7.4 m�ü Timing is matched with a cross correlation ü Time difference between data and simulation
is explained by cable delay etc. ü Agreements are reasonable
ü Prepulse seen �
Data Simulation�
Δt = 137.5 ns Δt = 138.9 ns
Δt = 139.7 ns
17/07/14� 18�
■ Residual signal (notarget)0 m� 3.5 m�
7.4 m�ü Similar shape ü Similar amplitude
ü Time correlates with signal
→ generated at source? Prior to the signal? ü 10 ns earlier (3 m below the cover box)
ü From the end of the beam pipe?
ü No distance dependence?
Data - Simulation�
17/07/14� 19�
■ Spectrumagreements(notarget)
0 m� 3.5 m�
7.4 m�ü Similar behaviors ü Difference becomes larger at high height
because the signal is weaker and the effect of additional component is larger�
Data Simulation�
17/07/14� 20�
■ Residual spectrum (notarget)0 m� 3.5 m�
7.4 m�ü Quite similar shape ü Flat spectrum →�White noise?�
14th, July, 2017, ICRC2017
■ TheARAsensi/vity
ARA37 (3yr)�
ARA Test Bed limit�
ARA2 limit�
K.Mase 21
14th,July,2017,ICRC2017 �
■ Reproducibility
Vpol � Hpol �
The reproducibility was checked with data with the same configuration
2015/01/14 Run1 (ice 60 deg., 0m)
2015/01/14 Run4 (ice 60 deg., 0m)�
The difference in the amplitude is 5% → 10% in power (Vol) �
K.Mase� 22�
14th,July,2017,ICRC2017 �
■ Stability and far field confirmation ü Thestabilitywiththesame
configuraFon:5%inamplitude
ü TheantennamastwasintenFonallyrotatedby~15deg.
ü ThesignalamplitudedecreasedproporFonallywiththedistancechange.→FarfieldconfirmaFon(3.0nsFmedelay→11%distant→12%amplitudedecrease)
ü TimedifferencefromtheexpectaFonwascheckedforeachconfiguraFon.
ü Thespreadis1.9ns→9°rotaFon→6%inamplitude
ü TheoverallsystemaFcuncertaintyinpower:16%
15 degrees�
2015/01/14 Run1 2015/01/14 Run3 (3.0 ns delay corrected)
Configuration: Ice 60°, obs. angle: 0°, Vpol
K.Mase� 23�
14th, July, 2017, ICRC2017
■ TheARAsystem
DAQ box�
optical fiber (~200 m)�
DAQ at surface �
LNA�
in-ice �
~40 dB�
band-pass filter �
Antennas�
calibrate these detectors�
V-pol antenna Bicone
150-850 MHz
�
H-pol antenna Quad-slot cylinder
200-850 MHz
Gain similar to dipole (+2 dBi)
�
~40 dB�
K.Mase 24
14th, July, 2017, ICRC2017
■ Schema/coftheARAsystem
DAQ box�FOAM �DTM�
optical fiber signal transfer system�
Antenna�
optical fiber (200m)�
band-pass filter �
DAQ at surface �LNA� DTM� FOAM �
in-ice �
~40 dB�
K.Mase 25
14th,July,2017,ICRC2017
■ Antennas
V-pol antenna Bicone
150-850 MHz
�
H-pol antenna Quad-slot cylinder
200-850 MHz
Gain similar to dipole (+2 dBi)
�
K.Mase 26
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