Kumiko Kotera - Institut d’Astrophysique de Paris - CNRS

Chiba U. - 19/04/2023

GR ND

γ

ν

GW

Fe
p

Towards
EeV Neutrino Astronomy
with GRAND(Giant Radio Array for Neutrino Detection)

flUnderstanding the violent Universe?

AGN/Blazars

ares, time-variabilities

Young pulsars
Neutron starmergers

Magnetars(AXP/SGR)Long
Gamma Ray
BurstsBlack holemergers

Tidal disruption
eventsSuperluminous
Supernovae
2Exploring the high-energy Universe with multi-messengers
Gravitational waves

Cosmogenic neutrinos

produced during propagationin the intergalactic medium

Cosmic rays

p Fe

Astrophysical neutrinos

produced at the source

Gamma rays

γ

γ

ν

ν
Neutrinos• not de ected by magnetic elds
• allow us to see farther in the Universe• allow us to see deeper in objects• clear hadronic acceleration signature
fi

fl

3

UHE neutrinos: the unchartered territory!

GR ND
2015 2002

Evolution of UHE neutrino science casee.g., Møller et al. 2018,
van Vliet et al. 2019

BOOM of multi-messenger astronomy+ time domain astronomy at HE
GR ND
2015

IC170922 inother possible
coincidencewith TXS 0506+056 coincidences
2017

2021

new TDEs, magnetar ares, blazar ares, FRBs,
gamma-ray bursts, superluminous SNe…
First
gravitational
waves detectedν

GW astronomy begin!
kilonova associatedwith GW170817

γ
GW

of course very interesting,but less of a priority?
Let's catch thedi use cosmogenic
neutrino ux!
Point sources!
Transient neutrino
sources!

What will we need?

✓ Excellent sensitivity✓ Sub-degree angular

fl

fi

fl

fl

ff

resolution✓ Wide instantaneous eldof view

Radio detection of ultra-high-energy air-showers
UHECR
vertical shower

Xmax
few
kms
~10 kmgeomagnetic e ect:radio signal
few 10s to100s MHz~400
m~400 mτ>30 kmνradio detection: a mature techniqueradio antennas: scalable, cheap, robust

AERA, LOFAR, CODALEMA, Tunka-Rex, TREND

ideal for giant arrays

ff

6

example of sub-array locations

Le concept de GRAND
200'000 radio antennas over 200'000 km2~20 sub-arrays of 10'000 antennas
over favorable sites worldwide

Argentina

China
San Juan

GR ND
GRAND10k
10,000 km2

Diamante

Proto300

Malargue

300 km2

Full GRAND

GR ND

200,000 km2

Proto300@AugerLos Menucos
Somuncura✓ Radio environment: radio quiet✓ Topography: mountains/slopes✓ Access, Installation and
Maintenance✓ Other issues (e.g., political)

several excellent sites identi ed
in Argentina & China(~100 measurements,14 campaigns)

fi

fi

7

GRAND Science & Design, GRAND Coll.
Science China, arXiv:1810.09994

Simulated performances

ity principle study
c topography

Pulsars: Fang et al.

35

(7.5
SE
HE
be
Cu
Ice

10°8

ube
C
e
c
I

Blazars, Rodrigues et al.

u.l.

PO
EM
GR
M
AAN
36
D2
0(
00
10
k(
yr
10
)
yr
)

µ (et
Alves Batista
10al. 2018yr)

Cosmogenic, standard
Cosmogenic, pessimistic

-G
O
RN
0
(1
)
yr

All-flavor flux En2 Fn ( En ) [GeV cm°2 s°1 sr°1]

IceC
ube
n

u.l.
ger
Au

10°7

yr)

10°9

10°10

GRAND200k integ. (10 yr)

r a 20 000 km2
ne : nµ : nt = 1:1:1
h a 1 km spacing
S from realistic isotropic flux

105

M. Bustamante

106

en2
G
IC

Decoene et al., 2022 arxiv:2112.07542

)
0 yr
1
(
io
rad

Angular resolution~0.1°

Decoene et al., 2022

table with results

107

108

109

Neutrino energy En [GeV]

1010

1011
angular resolution [deg]Validation of the reconstruction for the neutrinos:
emissionvery well constrained• source• GRAND fullsensitivity
to neutrinos(E>1017 eV) ~4 x 10−10 GeV cm−2 s−1 sr−1
• arrival direction within the targeted goal of 0.1°
26
Decoene et al., 2022
• Angular resolution ~0.1° for GP300 & GRANDn and gamma

B. Lago & Rio GRAND team
• Energy resolution < 10% on air-showers for GP300 & GRAND
Decoene et al., 2022
• Xmax resolution < 40 g/cm² for E>1017 eV (comparable to other methods)8

of EM instruments• development of MM-networks,
LHAASO
100 GeV−1 PeV
gamma

20 GeV−300 TeV—> false associations will beCTA
extremely common
100 GeV−100 TeV+
narrow
down
searcharea• skim interesting events HAWC
30 GeV−100
TeV
H.E.S.S.
50 GeV−50 TeV
MAGIC—> requires angular resolution
85 GeV−30 TeV
VERITAS

PUEO

ARA
RNO-G
ARIANNA-200
RET-N
IceCube-Gen2 RadioBEACONGRAND10k
GRAND
Auger
TAMBO
POEMMA Cerenkov
Trinity
Ashra-NTA

Diﬀ.
sens. lim.
XMM-Newton

iFoV ang.0.2−12
res. keVin sky %Athena-WFIin GeV cm−2 s−1 sr−1

X

>2030

0.1−15 keV

15−150 keV
4.2×10in 30 d6
<2.8°
Swift −8BAT
−90.2−10 keV
XRT
3.6×10(2030)
35
5°
di cult to reach sub-0.16−0.62 µm
1×10−8UVOT
in 5 yr30
2°×10°
4−150 keVSVOM
ECLAIRs
degreeresolution
forin8×10−9 in 5 yr
50
2.9−3.8°
0.2−10 keV
MXT
3×10−105 VT
yr
50?0.4−1 µm
iceininstruments
4×10−10 in 5 yr
43
2°×10°ASAS-SN
380−555 nm
1.2×10−8 in 5 yr
60.3°−1°420−975 nm
ATLAS−8 in 5 yr
1×10
6
0.1°
400−900 nm
Pan-STARRS−10 in 5 yr
4×10
45
0.1°
400−650 nm
ZTF−8 (2019)]
0.3−1 µm
Rubin Obs. (LSST)[1.5×10Vera30<1°400−800
nm
MASTER-II(VWF)?
271°
350−980 nm
TAROT−8 in 5 yr
7×10
0.6
0.4°
0.36−1.03 µm, spec
GEMINI−10 (GMOS)
1×10
in
5
yr
6
<1°
0.365−1.05 µm, spec
GTC (OSIRIS)−10 in 5 yr
2×10
30
0.1° µm, spec
0.32−1
Keck (LRIS)

multi

2025 oLAT
GBM
INTEGRAL IBIS
SPI-ACS

IR/optical/UV

2021 o20 MeV−300 GeV
10 keV−25 MeV
15 keV−10 MeV
100 keV−2 MeV

Fermi

VLT (X-shooter)

0.3−2.4 µm, spec

ffi

radio

VLA
1−50 GHz
adapted from Guépin, KK, Oikonomou,
Nature Phys. Rev. 2022
MWA
SKA1(2)-MID

80−300 MHz
350 MHz−15.3 GHz

2021
o
2025
o
>2030
Diﬀerential
sensitivity
limit

Energy range
FoV
ang. res.

Diﬀerenslew [sgammaEnergy range−14 erg cm−2 s−1 in 1 yr
LHAASO
5×10−2 s−1 in 50 h
6×10−14 erg cm
CTA−13 erg cm−2 s−1 in 1 yr
6×10
HAWC
−13 erg cm−2 s−1 in 50 h
6×10
H.E.S.S.
−13 erg cm−2 s−1 in 50 h
9×10
MAGIC
−13 erg cm−2 s−1 in 50 h
6×10
VERITAS−13 ergLAT
5×10
cm−2 s−1 in 10 yr
Fermi−2 s−1 in 1 s
GBM
2 ph cm−12 erg cmIBIS−2 s−1 in 103 s
1.2×10INTEGRAL-1 in 106 s
10−3 ph cm−2 s−1 MeV
SPI-ACS100
2 sr GeV−1 PeV
0.3°
20 GeV−300 TeV
10−20°< 0.15°100
2 srGeV−100 TeV
0.1°
305°GeV−100 TeV
0.1°
50
3.5°GeV−50 TeV
0.07°
85
3.5°GeV−30 TeV
0.1°
20
GeV
2.4MeV−300
sr
0.15°
10
9 srkeV−25 MeV10°26415deg
keV−10MeV
0.2°
100
4" keV−2 MeV -

−14
5×10
[2/3
6×10−14
18
−13
6×10
[2/3
6×10−1310
9×10−13
6×10−13−13
5×10[all2[allph
1.2×10−10
10−3 ph c−15 erg cm−2 s−1 in 106 s
10XMM-Newton
3×10−16 erg cm−2 s−1Athena-WFI
in 105 s

0.2−12 keV 6
0.5°
2
0.4 deg0.1−15
keV < 5

10−15 e3×10−161-10 ergBAT
6×10
cm-2 s-1 in 2000 s
Swift
5×10-13 ergXRT
cm−2 s−1 in 104 s
UVOT
19 magin 300 s−1 in 103 s-10
7.2×10 SVOMerg cm−2 sECLAIRs
2×10-12 erg cm−2 s−1MXT
in 3000 s
VT s
22.5 mag in 300

keV 0.4°
1.415−150sr20.1 deg0.2−10keV 18
0.1 0.16−0.62deg2µm2.5
4−150 keV < 0.2°
2 sr
2
1 deg
0.2−10keV 13
2
0.2 deg0.4−1 µm < 1

6×10-10
5×10-1319
7.2×10-10
2×10-12
45e
22.

multi

>2030

ASAS-SN
19.5 mag in 30 min
ATLAS
19.7 mag in 30 s
Pan-STARRS
23.1 mag in 904 s
ZTF
21.0 mag in 300 s
Vera
Rubin
24.5
mag
in 30Obs.
s (LSST)MASTER-II(VWF)
19(12)
mag in 1 min(5 s)
TAROT
18.5 mag in 180 s
GEMINI
25 mag(GMOS)
in 2.5 days
GTC27
(OSIRIS)mag in 1 h
Keck23(LRIS)
mag in 20 s
23 magin 60−120 s
VLT(X-shooter)

IR/optical/UV

2025 oradio

2021 oX

The angular resolution is key for multi-messenger networks

VLA
186 µJy in 1 min
MWA
4.6 mJy at 1 s
2(0.1)µJy in 1 h
SKA1(2)-MID2
72 deg380−555
nm 7.82
29 deg420−975
nm 2
2
14 deg400−900nm
1.0−1.3
2
47 deg400−650 nm 2
2
9.6 deg0.3−1µm 0.7
2
8(400)400−800deg
nm1.9222
4 deg
350−980 nm 3.5
30.23'20.36−1.03µm,0.07/pix
spec
2
0.02
deg
0.365−1.05µm,
spec0.127/pix'2
46.8
0.32−1 µm, 0.135/pix
spec
2.2'2
0.3−2.4µm,0.173/pix
spec

19.5
[vis.
[4×vi
19
23.
[vis.
21.s
[vis.
[10024d19(12)
30°
18.
25
objm
2
ob
21
23
m
obj

2 GHz 0.12
0.16 deg
1−50
610 80−300
deg2
MHz 0.9'1(10)deg2
350 MHz−15.3
GHz
0.04°−0.7°

18
[20
o4
2(0

9

A wide instantaneous eld of viewfor more chances of spotting short transients
A wide daily eld of view for more chances of spotting longer transients

2021 oGR ND

by Foteini Oikonomou

instantaneous FoV (45% sky)
10 random* site locations

2025 o

>2030

PUEO
ARA
RNO-G
ARIANNA-200
RET-N
IceCube-Gen2 RadioBEACONGRAND10k
GRAND
Auger
TAMBO
POEMMA Cerenkov
Trinity
Ashra-NTA

No gain from Earth rotationfor South Pole instruments
Diﬀ. sens. lim.
iFoV good!)dFoV ang. res.
(but
iFoV
very
−2
−1
−1
in sky % in sky %in GeV cm s sr
4.2×10−8 in 30 d
3.6×10−9 (2030)
1×10−8 in 5 yr
8×10−9 in 5 yr
3×10−10 in 5 yr
4×10−10 in 5 yr
1.2×10−8 in 5 yr
1×10−8 in 5 yr
4×10−10 in 5 yr
[1.5×10−8 (2019)]?
7×10−8 in 5 yr
1×10−10 in 5 yr
2×10−10 in 5 yr

6
35
30
50
50
43
6
6
45
30
27
0.6
6
30

19
<2.8°
20
5°
35
2°×10°>50 2.9−3.8°>50?
432°×10°
19.5
0.3°−1°
80
0.1°
100
0.1°
92.8
<1°
62
1°
18−36
0.4°
62
<1°
>50
0.1°

adapted from Guépin, KK, Oikonomou, Nature Phys. Rev. 2022

*uniformly spaced between 60N and 40S

impossible to reach fullsky with a single site

fi

fi

10

UHE neutrinos• UHE neutrino astronomy• UHE neutrino cosmogenic ux

UHECR, hadronic physics

EeV
neutrino
astronomy

neutrino physics
A dv a nced

GZK
neutrinosges

ediate stages• neutrino cross-section
measurements• spectral, angular distortions• avor ratios

rm
Inte

UHE
gamma
rays

Giant
radio
pulsesradio-astronomy
in a novel way

sta

Neutrino
physics• 20-80 times the exposure ofAuger!
UHECRs• GRANDProto300:
transition from Galactic/
extragalactic• hadronic physics: muon
discrepancy, UHECR mass
Epoch ofcomposition, p-air cross-section
reionization

Fast
radio
bursts

UHE gamma rays
• competitive with Auger at
GRANDProto300 stage

Early stages• unphased integration of signals: an almost fullsky survey of radio signals• can detect FRBs and Giant Radio pulses of the
Crab already at the GRANDProto300 stage
11

fl

fl

A rich science caseA staged approach with self-standing path nders
Prototyping

GRAND200k

203X

2025

autonomous radio detectionof very inclined air-showers

1st GRAND sub-arraysensitive all-sky detector

cosmic rays 1016.5-18 eV• discovery of EeV neutrinos
for optimistic fluxes• radio transients (FRBs!)

1st EeV neutrino detection
and/or neutrino astronomy!

• 10,000 radio antennas over
10,000 km2• 200,000 antennas
over 200,000 km2• 20 sub-arrays of 10k antennas• on different continents

13 M€

300M€ in total• Galactic/extragalactic transition• muon problem• radio transients• GRAND@Nançay: 4 antennas
for trigger testing• GRAND@Auger: 10 antennas
for cross-calibration• GRANDProto300: 300
HorizonAntennas over 200 km²

2 M€
100 antennas produced
funded by China+ ANR PRCI NUTRIG (France)+ Radboud University

1500€/unit500€/unit

to be divided between
participating countries

12fi

Budget

Setup

Goals

2022

GRAND10k

ROTOTYPE

GRANDProto300 & other prototypes: experimental setup

HorizonAntenna,
successfully tested in thefield (Aug., Dec. 2018)

Deployment of 13
antennas in Gansu (China)

deployed
2 month ago!

Layout: 300 antennas, 200km²,
1km step size with denser infill
Erange = 1016.5-1018eV

deployed
Deployment of 4 antennas 6 months ago!

this summer in Nançay
radio observatory (France)
trigger testing
Deployment of
10 antennas
on the Auger site in
Malargüe, Argentina
cross-calibration

deployed
3 weeks ago!

Electronics:

50-200MHz analog
filtering,
500MSPS sampling
FPGA+CPU
Bullet WiFi datatransfert

13

Nançay Radiotelescope

GRAND@Nançay

Nançay Radio
Observatory

With the support of ANR-DFG "NUTRIG" program

Next steps• Nançay: • 4 antennas deployed in Nançay!

Modification from GP300 setup

by LPNHE
andRadboud
University• 3-unit setup(triangleof ~100+
m base)mid October 2022
• To be completed
by 4thfor
unittriggeringsometimeandin 2023• Test bench
GP300 antenna hardware• Charles•@ Currently
Nançay on working
Oct 20-21onforloweringcommissioning(+ testof unit forradiationof stations

Initialtests
Strong FM background Î FM stop-band filters on 3 channels

No Wifi allowed on site Î transfer through optical fiber

GRAND antennas in the woods
Marion Guelfand installing cables

Charles Timmermans
explaining dataacquisition to GRAND
team members

GP300 unit

50m

A French-Dutch collaboration to setup GRAND@Nancay• NUTRIG: kick-off meeting @ Karlsruhe October 17• Status & detailed discussion of work by Jelena, Lukas, Marion & Pabloattend!]60dB
Att.
Pablo Correa & Olivier
Martineau &a GRAND antenna

Spectrum is as expected (+wiggles @ higher freqs)
14• Hainan & Dunhuang• From
4th July to 10th July
GRANDProto13
in Xiao Dushan• Six Sites in Dunhuang:
better• Four Sites in Hainan• 13 antennas deployed in Xiao Dushan!
prefecture: strong FM
by Xidian U. & Purple Mountain Observatory
noise• Data being taken• Data being processed/analyzed by PMO, Xidian,Paris groups

Xiao Dushan• Xihu （Nature reserve ）DunHuang
E: 93.805517; N: 40.013594• South valley
E: 93.954130; N: 40.567251• Yadan（ national park ）E: 93.101448; N: 40.591506• North valley
E: 94.240825; N: 40.919965• Crater
E: 93.943667; N: 40.809585• Xiao dushan
E: 94.052693; N: 40.956192

North Valley
CraterYa DanSouth Valley

Hainan~120kmDun Huang
Xi Hu

74km

Altitude avg. 1100m

Yiren Chen, Bohao Duan,
Pengxiong Ma, Pengfei
Zhang, Yu tang, Shen Wang,
Xiaoyuan Huang

Few nice transient pulses
identified in the data - Plot by
Pablo Correa

Shen Wang and Bohao Duantaking data

GRAND@Auger - Malargüe, Argentina
Malargue• Deployment of 4 units by Radboud U. + U. Federal
do Rio de Janeiro• Data transfer will be possible by 4G
remote access to the Central DAQ possible
All 4 deployed units running!

Emotional: connected to theCentral Data Acquisition System
of GRAND@Auger from Paris

Fred Magnard installing a
PiKVM to the DAQ at IAP

Frist trace measured: History in the making!
with C. Timmermans & B. de ErricoJoão de Mello Neto, Charles Timmermans andBeatriz de Errico with their first GRAND@Augerantenna deployed, also with Juan Pablo Góngora
16

GRAND@Auger: an international prototyping e ort
International agreement for the GRAND@Auger project

Deployment at the AERA (Auger) sitearties (listed in alphabetical order)Dec 14th, 2022

y[m]amended 22/12/2022

tting themselves to the agreement including the full names, the names of their organisations, and their addresses

17500
RU/Nikhef phase I
RU/Nikhef phase II
RU/Nikhef 3d
KIT/BUW phase I
KIT/BUW phase II
KIT/BUW 3d
KIT/BUW low band

17000

A. Fundación Ahuekna (AHUEKNA)
16500
Av. del Libertador 8250, C1429BNP Ciudada Autónoma de Buenos Aires, Argentina
B. Institut d'Astrophysique de Paris (IAP)
CNRS/INSU et Sorbonne Université, 98 bis boulevard Arago, 75014 Paris, France
C. Karlsruher Institut für Technologie - Institut für Astroteilchenphysik (KIT)!
POB 3640, D-76021 Karlsruhe, Germany
D. National Astronomical Observatories, Chinese Academy of Sciences (NAOC)
20A Datun Road, Chaoyang District, Beijing 100101, China

88

92

99

108

16000

118

119

30
131

132

133

15500
142

143

45

32

33

34

38

46

39

47

107
6

48

41

42
1

2

4

3
7
10

11
13

50

51

52

53

54

55

61
71

14500

56

57

16

15

-28500

62
72

63
73

-28000

64

74

65

75

-27500

20

87
66

76

67

77

-27000

21

68

78

824

79

-26500

113

124

125

135

136

137

44

5
9

49

144

145

description

The parties listed in Section 1, are committed to carry out a cooperative effort to develop the
AND@Auger project, consisting in the deployment of a small array of 10 GRAND antennas on
ea of several kilometer square within the Pierre Auger Observatory. The scientific purposes ofoying the small array would involve cross-calibration and trigger studies for radio-detection of
inclined air-showers, initiated by ultra-high energy cosmic rays.

~4-7 events
per day

146

12
17

19

58

59

60

25

151

26

22

27

28

29

80

81

-26000

69

82

152

70

83

-255008485-25000E. Radboud University (RU)
Department of High-Energy Physics, P.O. Box 9010, 6500 GL Nijmegen, Netherlands

ackground/Purpose of the collaboration

126

14

18

15000

43

103

36
CRS

40

102

112

123

35

94

101

111

122

98

134
9137

110

121

31

100

109

120

93

157

-24500x[m]A. Benoit-Lévy,
M. Tueros, KK

PRELIMINARY!

The purpose of this agreement is to define the the responsibilities of the parties and the generals and conditions of the collaboration.

The development of the GRAND@Auger project relies on the authorization of the Augeraboration for land access and use, and for the exploitation of the existing Auger framework andpments.
ff

17

GRAND in Argentina

San JuanWith the support of CNRS IEA Argentina program
Deployment of 10 GRAND antennas at the Pierre
Auger Observatory site

Diamante

Perspectives: hosting one or more GRAND10k
sites in Argentina

MalargüeZ

Los Menucos

Somuncura

18

GRAND Technical Challenges

Autonomous trigger on radio signals• TREND: ~32% o ine identi cation e ciency• Noise = ultra-dominant: rejection 1/108• Identi cation of signals at various trigger levels,
methods to be developed e.g., Chiche et al. 2022
• Optimization of data collection

Reconstruction of primary particle parameters• good performances for vertical air-showers• no-man's land for inclined air-showers

Need for an
experimental setup
to test and optimize

GR ND@Nançay@AugerProto300

Develop new "conventional"
and machine learning methods
Industrial approach!

How to deploy/run 200k units over 200k km²?
How much will it cost? Who will pay for it?

low failure rates
deployment ~ electric poles

ffi

fi

ffl

fi

1919

The GRAND Software

https://grand-mother.github.io/

Developing tools to manipulate GRAND data:• A (ROOT) le structure• A database to manage simulations and data
• End-to-end simulation and reconstruction pipeline in development➔ Data challenges to foster developments with 3 segments:
DC0 (Electric eld simulations → GRAND le)
DC1 (Voltage computation)
DC2 (Electric eld computation & shower reconstruction)
Antenna response

DANTONν —> τ decay
backward MC over realistic
topography
Niess & Martineau 1810.01978

HorizonAntenna
h=5m, f = 50-200MHz, optimized forvery inclined trajectories Response
simulated in NEC4

Signal modeling

LayoutA. Zilles et al. 2020,
1809.04912
Chiche et al. ICRC 2021
Tueros & Zilles
arXiv:2008.06454

For GP300 with/without infill, for G10k
Effects of topography Decoene et al.
NIMA 2020
fi

fi

fi

fi

20

Signal modeling & air shower reconstruction
GRANDPa team (IAP+Obs. Nice)
S. Chiche, M. Guelfand,
K. Kotera, S. Prunet, C. Zhang
et al.
IFLP (Argentina)
M. Tueros

Radio-signal modeling(theory)

for very inclined air-showers
Chiche et al. 2022
Chiche, Zhang et al. in prep.
Guelfand et al. in prep.

KIT
T. Huege

Signal modelingfor triggering

We cannot run simulation

Run simulations (+inte
then prune antennas towithin the
NuTRIG project
KIT
L. Gülzow, T. Huege,
J. Petereit

TREND air-shower signal
Plot by A. Benoit-Lévy

PMO
Kewen Zhang
VUB (Belgium)
K. de Vries, F. Schlüter

GRANDPa team
(LPNHE+IAP+Obs. Nice)
J.-M. Colley, V. Decoene,
C. Guépin, E. Hivon, K. Kotera,
O. Martineau, S. Prunet, et al.
IFLP (Argentina)
M. Tueros
PMO
K. Zhang
Rio-GRAND teamB. Lago, R. M. de Almeida

Parameter reconstruction
framework
Methodology development
Decoene PhD 2020
Decoene et al. 2112.07542
Implementation for a fast code

GRANDPa team
(CEA-List, LPNHE)
A. Benoit-Lévy, S. Le
Coz, G. Lévy, O.
Martineau

Machine Learning
methods for trigger Nanjing U.
& reconstruction
R. Koirala, S. Wang
Führer, Charnock &Zilles, 2019
Le Coz ARENA 2022

U. Chicago/LUPM
C. Guépin
Rio-GRAND team
B. Errico, B. Lago

GRAND in Japan?
data analysis, signal treatment & MM opportunities

Data analysis preparation• Development of data analysis pipeline• Signal treatment - trigger• Methods and tools for air-shower parameter reconstruction

Scintillators on GRANDProto300? (Gansu, China)• Development and installation of particle detectors• Testing coincident events• Drastically improved science case (muon discrepancy, UHE γ rays)

GRAND10k R&D• Optimisation of mechanical design• Optimisation of power management• Optimisation of communications & trigger• Reconstruction of very inclined air-showers• Trigger and shower identification

Developing multi-messenger analysis in GRAND• Messenger discrimination• Developing the alert system• Synergies with other instruments: IceCube, JEM-EUSO, TA…

22

GRAND Collaboration Meeting
Nijmegen, Netherlands, Jan. 2023

GRAND Today

93 collaboratorsfrom 12 countries

Particle detectors
Penn State U.

Science case
IAP
Nanjing U.
NBI
PMO
Penn State U

Electronics prototyping
Nikhef/Radboud U.
NAOC
PMO

Fast Radio Bursts
PMO
Obs. Paris/Nançay

GR ND
Simulations/data analysis
IAP
IFLP
KIT
LPNHE
Nanjing U.
PMO
UF Rio de Janeiro
VU Brussels
Warsaw U.

SoftwareWarsaw U.
IAP/LPNHELPC Clermont
UF Rio Janeiro

Antenna prototyping
Nikhef/Radboud U.
Xidian U.

Sitemanagement
PMO
NAOC

Unit production
NAOC
PMO
Xidian U.
23

GRAND Memorandum of Understanding
2023 version in progress(13 parties)

Memorandum of Understanding
for the Giant Radio Array for Neutrino Detection (GRAND) Collaboration

Memorandum of Understanding
for the Giant Radio Array for Neutrino Detection (GRAND) Collaboration

2022 version
amended 27/01/2022

amended ***1. Parties (listed in alphabetical order)

1. Parties (listed in alphabetical order)

committing themselves to the agreement including the full names, the names of their organisations, and their addresses

committing themselves to the agreement including the full names, the names of their organisations, and their addresses

A. Institut d'Astrophysique de Paris (IAP)
CNRS/INSU et Sorbonne Université, 98 bis boulevard Arago, 75014 Paris, France

A. Institut d'Astrophysique de Paris (IAP)
CNRS/INSU et Sorbonne Université, 98 bis boulevard Arago, 75014 Paris, France

B. Inter-University Institute For High Energies at the Vrije Universiteit Brussel(IIHE-VUB)
Vrije Universiteit Brussel, Pleinlaan 2, 1050 Brussels, Belgium

B. Inter-University Institute For High Energies at the Vrije Universiteit Brussel(IIHE-VUB)
Vrije Universiteit Brussel, Pleinlaan 2, 1050 Brussels, Belgium

C. Laboratoire de Physique Nucléaire et des Hautes Énergies (LPNHE)
CNRS/IN2P3, Sorbonne Université, Université de Paris, 4 place Jussieu 75005
Paris, France

C. Laboratoire de Physique Nucléaire et des Hautes Énergies (LPNHE)
CNRS/IN2P3, Sorbonne Université, Université de Paris, 4 place Jussieu 75005
Paris, France

6LJQDWXUHV
D. Nanjing University
163 Xianlin Avenue, 210023, Nanjing, Jiangsu, China
7KH IROORZLQJ SHUVRQV FRQFXU LQ WKH WHUPV RISignatures
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D. Nanjing University
163 Xianlin Avenue, 210023, Nanjing, Jiangsu, China

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E. National Astronomical Observatories, Chinese Academy of Sciences (NAOC)
20A Datun Road, Chaoyang District, Beijing 100101, China

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E. National
Astronomical
Chinese Academy of Sciences (NAOC)ZLOO EH XSGDWHG
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20A Datun Road, Chaoyang District, Beijing 100101, China

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Nov 26th 2021
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Center for Particle and Gravitational Astrophysics, Pennsylvania State University,
University Park, PA 16802, USA

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Nov 26th 2021
François Bouchet, Director)UDQoRLV %RXFKHW 'LUHFWRU-RUJHQ '¶+RQGW 'LUHFWRU

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G. Purple Mountain Observatory (PMO)
Chinese Academy of Sciences (CAS), No.10 Yuanhua Road, Qixia District,Nanjing 210023, China

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I. Universidade Federal do Rio de Janeiro
Av. Pedro Calmon, 550 - Cidade Universitária, Rio de Janeiro - RJ, 21941-901,
BrazilJ. University of Warsaw
Krakowskie Przedmieście 26/28, 00-927 Warsaw, Poland
K. Xidian University
No. 2 South Taibai Road, Xi’an, Shaanxi 710071, China+ LUPM (Montpellier) + Hellenic Open University

GRAND in the international community

GRAND appears in several roadmaps• Mid-term review of the APPEC strategy• Physics briefing book: Input for the European Strategy for Particle Physics Update 2020,section 7.3
http://cds.cern.ch/record/2691414• Nikhef strategic plan 2017-2022 and beyond, p. 43
https://www.nikhef.nl/strategisch-plan/• CNRS Prospective INSU Astronomie & Astrophysique 2020-2025, p. 34

https://www.insu.cnrs.fr/sites/institut_insu/files/news/2021-04/Prospective_INSU_AA_2019.pdf• Latin American Strategy for Research Infrastructures for High Energy, Cosmology, Astroparticle
Physics LASF4RI for HECAP https://drive.google.com/file/d/1muqdLMMQaZ-yBxFdYLPuCpOQgeSfsvtV/view• White Paper in the Decadal Survey 2020, Snowmass 2022

Environmental responsibility
GRAND Carbon Footprint Study
GRAND evaluates its environmental impact
arXiv:2101.02049
arxiv:2105.04610 (Nature)
One R&D goal: reduce the environmental impact of the detector

25

References:
Website:http://grand.cnrs.fr

GR ND

GRAND White Paper
https://arxiv.org/abs/1810.09994
Githubhttps://github.com/grand-mother/
GRAND Carbon Footprint Study
https://arxiv.org/abs/2101.02049
Documentary by Jean Mouette The Road to the Neutrino:
https://www.youtube.com/watch?v=8tDnwq8gAe4

26

GRANDProto300: a self-standing path nder
16.5-1018 eV
Autonomous detection of very inclined
cosmicrays E=10
Massseparationpower

1- reconstructing spectrum, arrival direction & composition

validation via comparison to known results
2 - test bench for further GRAND stages

Holt et al. 2019

tanks + radio (em. energy)

AugerPrimedesign goal

Proficient physics instrument
if complemented by particle detector array
Galactic/extragalactic transition
hadronic physics (muon content in EAS)
UHE gamma-rays
Fast Radio Bursts

ECR = 1 EeV
tanks + scintillators

Differential EventRate [day-1 PeV-1 ]Canonical Array
2
10
New mass estimator superior for inclined showers!

hadronic
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radio
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A. Zilles, et al. (including 0
V.D.)
analytic simulation (Radio Morphing)RM
conservative
RM
aggressive
conservative 50
Coneaggresive
40 0
0.8
100
100
1)
Cone conservative
Cone aggresive✓(cone modelling of the trigger 60
RM
conservative
aggressive
40
40 RM 100
cseveralcomputation
volume)
100
1.0
60
0.6
τ hourstotens
ofseconds
100
100
40
40
0.4
20
20
3 tools:
025- ZHAireS)50
75 80
0
25
50 80 75
(MC• microscopic simulation↵
20 RM conservative
20 aggressive
0.4
RM
topographies
increase
thefrom
detection
upof
to•secondsa8080
omputation
speedsA. Zilles, et al.
(including
V.D.)
semi-analytic
simulation (Radio Morphing)
0.0
several eﬃciency
hours
to tens
M
and
-30%
for
Cone)
100
100
h
40
40
0.8
5060
75
0
25
50
75
0.6
of the trigger
volume)80
60
study
80 • analytic computation (cone0modelling 25
0.4
ftivity
3 principle
nsistent
results (within 10% for RM and -30% for Cone)
ZHaireS conservative
ZHaireS aggressive
0.6
100
80 speeds
80of seconds100
RM conservative
RM aggressive
100
100
1.0
istic
topography
3
computation
fromseveral
hours
to
tens
•
40
40
ct remains constant
5°
to
20°
0.4
20 overDangles ranging from
20
60
60
Cone)
• consistent results (within 10% for RM
2050
20and -30% for25
0.6
0
25
0
50
75
0
75
0
25
50
75
60 25 75 50 60 80
60
60
80
0.2
20
20
80
80
0
25
50
75
0
25
50 0.2 75
0.2
RM
conservative
RM
aggressive
Two parameters to model the topography:
0.2
RM
conservative
RM
aggressive
100
100
100 40100
Effectsof
topography
40
40 40
60
60
0.8
depth
• D = valley100
Result:
0.4
0.0
60100
60
40
40
0.4
inclined
topographies
increase
thedetectioneﬃciency
up
to
a
•
80
80
• ⍺ = the mountain slope

0.4
0.4

°0.05 29

Building on features of the EAS radio signal• Frequency range : 30-200 MHz• Transient pulses, duration: <~ 100ns• Amplitude of detectable signals at unit level:> 3-5

air shower signal

noise level ~ 20 μV/mabove the stationary Galactic background( [Galactic emission] ~ 20 μV/m in [50-200MHz] )amplitude scales linearly with primary particle
energy• Detection energy threshold with 5 units incommon: 1016.5 eV

TREND• Emission ~ point-like around shower maximum—> spherical wavefront• Emission focused in 1º cone around shower axis
• "Cerenkov ring": enhancement around 1º at
highest frequencies

Adapted from Corstanje et al., arXiv:1404.3907

θ = 80°θ = 88°𝜎𝜎

𝜎

Plot by M. Tueros

30

Technicalradio signal
We cannotcharacteristics
run simulationsof
onthe
an infinite
number of configurations
air shower signal
Run simulations (+interpolation Tueros & Zilles 2020) on a dense array: 30-200 MHz• Frequency range
thenprune antennas
Transient pulses, duration:<~ 100nsto make new configuration•• Amplitude of detectable signals at unit level:> 3-5

trianglenoise level ~ 20 μV/mabove the stationary Galactic background( [Galactic emission] ~ 20 μV/m in [50-200MHz] )The Layout Pruning Tool!
amplitude scales linearly with primary particle
energyTREND• Detection energy threshold with 5 units incommon: 1016.5 eV

E = 1 EeV, zenith angle = 70

Vpeakpeak (arbitrary units)

•

𝜎

𝜎

𝜎

Plot by A. Benoit-Lévy• mask the information of the pruned an• recalculate triggered event rate with pr
Emission ~ point-like around shower maximum—> spherical wavefront• Emission focused in 1º cone around shower axis
• "Cerenkov ring": enhancement around 1º at
highest frequencies
trihex all (250), Nring = 20
triangles (hexagone + center)step 250 m
θ =390780° antennas
204.7 km2

θ = 88°Plot by M. Tueros

31Challenge 1: Air shower reconstruction
Center of spherical
fit of trigger times⬄ radio emission
sourceAnalytical description of amplitude distribution
V. Decoene PhD

ωGP300 simulations
σt = 5ns
σA/A = 20%
V. Decoene PhD
V. Decoene, OM, MT, arxiv:2112.07542

32

Challenge 2: self-triggered radio arrays• Only realistic solution for GRAND size
• At present (including GP300), only standard
methods for triggering:• L1 @ unit level: (mostly) signal-over-threshold

A TREND event

EAS signal known from simulation, backgroundcontinuously measured• L2 @ DAQ level: select causal coincs between L1s(GPS timetags)

Background is mostly waves rather thanrandom coincs• Full time trace collected

Huge data volume (~10kBy/trigger), while offline
treatment reduced to few infos (trig time,
amplitude, polar)…

Nxσnoise
σnoiseGRANDProto300: large volumes of data ➔ Large bandwidth needed ➔ WiFi
➔ High cost, high power consumption, low range

Need for a low-rate, low-power, low-price solution for giant arrays (e.g. GRAND10k)

33

The NUTRIG proposal
Karlsruhe & Paris (T. Huege, M. Roth, KK & OM)• L1 trigger (LPNHE lead)• Developing innovative methods for:• Signal identification (ie fighting against
transient noise) ➔ improve purity• Signal extraction (ie fighting against
stationnary noise) ➔ improve threshold• Specific constraints:• Online treatment (ie faster that data rate)• « Frugality »: low power & limited CPU• Noise variability: large range of backgroundpulses, not-so-stationnary baseline conditions

M. Erdmann et al., arXiv:1901.04079• L2 trigger (KIT lead): use EAS
signatures• Data format (LPNHE + IAP + KIT):• Optimize balance between data volume
and quality using offline (blind) analysis
based on reduced info.
S. Chiche et al., arXiv:2202:06846

34

The NUTRIG proposal
Karlsruhe & Paris
Communication with DAQ
GP300: Ubiquity Bullet. Range: ~10kms.

GP300 (nominal) rate:
L1: 4kBy/s/unit
L2: 100kBy/s/unit➔ 104kBy/s/unit
Communication with GP300 units
GP300: 5 Ubiquity AirMax Rocket for 300 units.
Max throughput: 190MBy/s in total.

Level-one trigger
info from unit to DAQ
GP300 rate: 1kHz x 4By = 4kBy/s.
NUTRIG target rate:
100Hz x 10By = 1kBy/s.

Level-two trigger
request from DAQ to units
with level-one triggers

GP300 unit

Level-two trigger
info from unit to DAQ
GP300 rate: 10Hz x 10kBy = 100kBy/s.
NUTRIG possible target rate:
1Hz x 500By= 500By/s.

FrontEnd electronics: signal digitisation,level-one trigger & level-two trigger info formation
GP300: level-one trigger issued when pulse exceeds threshold (typically 5 x
stationnary noise). Level-one trigger info: GPS time stamp (4By). Level-two
trigger info: 3µs timetraces for 3 channels (10kBy ).
NUTRIG: level-one trigger issued if extracted transient signal compatible
with air-shower pulses (obj B). Level-one trigger info to be defined (obj B &C). Target size: 10By.
Level-two trigger info: to be defined. Possible target size: 500By.

DAQ room

DAQ room: level-two trigger
and data recording
GP300: level-two trigger issued if 5+ GPStime stamps from level-one triggers are incausal coincidence.
NUTRIG: level-two trigger issued if combinedlevel-one trigger infos compatible with air
shower model (obj C).
Level-two trigger infos saved to disk foroffline analysis.

NUTRIG target:
L1: 1kBy/s/unit
L2: 500By/s/unit➔ 1.5kBy/s/unit
NUTRIG goal (2025):
Optimized trigger
methods forautonomous radioarrays+Precise quantitativeevaluation of data rate
Following step
(starting 2024): define
hardware layer
adapted to data rates➔ GRAND10k
35

CLASSICAL picture for radio emission
2 main sources for the radio emission

Vertical air-showers: well known, mature and verified
Inclined air showers: still several challenges, trending topic
e.g., Schlüter et al. 2022, Chiche et al. 2022

Characteristics of inclined air showers• development at lower air density• development over longer trajectories
verticalinclined

100

km

ρ0
10 km

ρ1

decreasing ρρ2
ρ3How do all these characteristics affect the radio emission?
Enhanced effect of B!
• particles more deflected —> larger lateral shower extension —> coherence loss?
• particles more deflected —> synchrotron emission?
slide adapted from S. Chiche 37

s
g
⇠

2

s
c
⇠
h

f
d
d
h
e
e
r
y
o
l
-

-

Coherence and synchrotron conditions
Xmax : maximum

λ

Llat

shower extension

2high energy particles. At energies
Xmax ✏e > 10 MeV, electronsand positrons in the cascade undergo Bremstrahlung
scattering, with attenuation length lrad = X0 /⇢air ⇠
DXmax
3
3
1
2
3.67 ⇥ 10 m (⇢air /1 g cm ) , where X0 = 36.7 g cm
the electronic radiation length. The produced electronsand positrons are also deflected by the Earth magnetic
sketch courtesy: S. Chichefield in opposite directions, with Larmor radius rL ⇠3.3 ⇥ 104 m (✏eCollision/100 MeV)(B/10 µT) 1 , with B the Earthmagnetic field.
In the commonly admitted paradigm of radio emission by air-showers, two processes account for most of
the electromagnetic signal. The major process, called
FIG.
1. Characteristic
updated).
“geomagnetic
emission”, is lengths
produced(toby beelectronsand [”Incoherence”
theatlabel]positronsfor
drifting
the front end of the shower, through
1. Characteristic
lengths(to be updated).
[”Incoherthe competinge↵ects ofmagnetic deflection
syn
Earth
rad
air
lat airEarth
coh and particle FIG.
ence” for the label]scattering mentioned above, and hence producing a timevarying current [11]. In the other process, called “charge
Historically,
synchrotron
radiation
believedhighenergy particles.
Atwas
energies✏e >to10be
MeV, electrons
Spatiallength:excess”
or coherence“Askaryan”
mechanism,
electrons
from
the
air
Inelasticcollision
radiation
lengthHistorically,
synchrotron
radiationAt
wasbelievedhighenergy particles.
energies✏e >to10be
MeV, eandpositronsinthecascadeundergoBremstrahlung
atomsmain
accumulateintheshowerfront,
creatinganet
negthesourceoftheradio
emission(originallycoinedhigh energy particles. At energies ✏e > 10 MeV,
electrons
the main sourceandof theradio emission(originallycoinedpositronsin the cascade
undergoBrems
ative charge
excessalong
theshowercore,
comparatively
scattering,withattenuation
lengthl=X/⇢⇠“geosynchrotron”
emission).
Intheframeworkofvertical
rad
0
air
and
in thelatcascade undergo Bremstrahlung
coh positrons
Xmax
scattering,withattenuation
lengthlrad = X0“geosynchrotron”
emission).
In theframeworkof verticalto the outskirts. The
lattermechanism
was
shown
3
3 to1
2
3
3
1
3.67
⇥
10 m (⇢shown
g cm
g 10
cmm (⇢shown3.67 however⇥) ,awhere
X0 = 36.
air /1length
0 =air-showers,
it
wasto have
negligible
scattering,withattenuationl)rad , a=whereX0 /⇢Xair⇠36.7
air /1 g cm
air-showers,
howeverhavenegligible
represent⇠ 10%itof was
the
total
radio emission
fortoverticalelectronic
radiation3
2 theelectrons
contribution,in the GHz
regimelength.
[? ]. The produced etheelectronic
radiation
length.
3.67lateral⇥and103lessm(⇢/1
g%cmfor) 1regime,inclined
whereX0]. =The
36.7produced
g cm except
contribution,
exceptinGHz[?
air-showers,
thanfewthevery
airairShowerextent:andpositronsarealso deflectedby the Earthm
In
principle,anonnegligible
synchrotron
component
isandpositrons
arealso
deflected
by
the
Earth
magnetic
showers[12].
electronic
radiation
length.
The produced
electrons
In theprinciple,
a nonnegligible
synchrotron
componentisfield canin opposite
directions,with Larmor
radi
expected
if
particles
radiatebeforeundergoing
BremSynchrotron
lengthWe anddemonstrateinthearefollowing
sectionsdirections,that
de-Earth
field
in also
oppositewithLarmorradiusr4Lm (✏for⇠e /100
3.3 ⇥ cooling
10i.e.,
MeV)(B/10µT) 1l, with
B th
deflected
bythisthemagnetic
lat positronstransverse
expected
if
particles
canradiatebeforeundergoing
Bremstrahlunginteraction,
l
/l
<
1,
where
=
syn
rad
syn
4 inclined air-showers, re1
scription breaks downforveryfield.
2Bmagnetic
2
2
1
3.3
⇥
10
m
(✏
/100
MeV)(B/10
µT)
,
with
the
Earth
e
field
in
opposite
directions,with
Larmorradiusr⇠
3
3 (B/50 µT) 3 (⌫/80 MHz) 3
L
1157
m
(
/Z)
(✏
/88
MeV)
strahlunginteraction,
i.e.,
for
l
/l
<
1,
where
l
=
e
syn
rad 1
syn
quiringτ:acharacteristic
drastic4 revisiontimeof theexisting
paradigm.
In the commonly admitted paradigm of radof field.
inelasticcollision
magnetic22
21synchrotron cooling length.
38
is theFrom thiswe
3.3 ⇥ 10 m (✏e /100 MeV)(B/10 µT) , with [14]
B the
Earth
sion by air-showers, two processes
accountforγ

Condition for coherent emission

L (ρ , B

)<l

l

= λD

/L

L

=x

(t = τ)1157 m ( /Z) 3 (✏e /88 MeV) 3 (B/50 µT)

Condition for synchrotron emission

l (B

3

(⌫/80 MHz)3

) < l (ρ )New paradigm for inclined air-showers
CLASSICAL radio emission:
Coherent
geomagnetic+
charge excess

synchrotron
contribution

θ [Deg.]incoherent
emission

Incoherent
emission

Coherent
geomagnetic+ synchrotron

Chiche, Zhang, KK, et al. in prep.

39

Conditions for a coherent radio signal
Strong radio emission only if shower lateral extent shorter than coherence length

Llat(ρair , BEarth) > lcoh
Xmax : maximum

Llat

shower extension
Xmax

λ
DXmax

Collision

Spatial coherence length:lcoh = λDXmax /Llat From ZHAireS simulations?

Shower lateral extent:
Transverse velocity:
Transverse position:

Llat = xtransverse(t = τ) τ: characteristic time of inelastic collision

τc 3eBEarthvtransverse(t) =(1 − e −t/τ) (Scholten et al., 2007)ℰ(t)τ 2c 3eBEarth t/τt
xtransverse(t) =(e − 1 − )ℰ0τsee also
Marion's
studies onparticle
distribution in
air-showers!40

tromagnetic
signal.
The ofmajor
process,
called and particle
Earthmagnetic
FIG. 1. Characteristic lengths (to be upd
the competinge↵ectsmagnetic
deflectionseealso C. James (2022)
gneticemission”,
is produced
by electrons emission
and
ence”
for
the
label]
orradiusr⇠
ConditionforsynchrotronLscattering mentioned above, and hence producing a times
drifting
the front end of the shower, throughithvarying
B the atEarthcurrent[11]. Indeflection
the otherprocess,
called“charge
FIG.
1. Characteristic lengths (to be updated). [”Incoherpetinge↵ectsofmagnetic
andparticlecally,
synchrotron
radiation
wasbelievedtobe label]
excess”
or“Askaryan”
mechanism,
electrons
from
the
air
ence”
for
the
ngofmentioned
above, and hence producing a timeHistorically, synchrotron radiation w
radio
emisatoms
accumulateintheshowerfront,
creatinganet
negsource
of
the
radio
emission(originallycoinedcurrent [11]. In the other process, called “charge
the main source of the radio emissionunt
for charge
most ofexcess along the shower core, comparatively
ativeor “Askaryan”
mechanism, electrons
the air
hrotron”
emission).
In the fromframeworkofHistorically,
vertical synchrotron“geosynchrotron”
emission).
In thefra
process,
calledradiation
was believed
to beto the outskirts.
Thelattermechanism
ccumulatein the shower
front,
creating
a net neg-was shown tors,
it wastoemission
have afor
negligible
was however
shown
to
yarge
electrons
andthemain sourceair-showers,of the radio it
emission(originallycoinedrepresent⇠ however10%
the shown
total
radio
vertical
excessalong
the ofshowercore, comparatively
2“geosynchrotron”
emission). Inexcept
the frameworkof verticalcontribution,in the GHz
regim
shower,throughion,
exceptin theGHzregime[?
outskirts.
The andlattermechanismwasshownto]. inclined
air-showers,
less
than
few
%
for
very
airFIG. 1. Characteristic lengths (tobe updated).
[”Incoher2tonegligibleγ
air-showers,
itwashowevershown
have a negligibleionandparticleIn
principle,anonsynchro
nt
⇠
10%
of
the
total
radio
emissionforverticalSynchrotron
showers[12].
Inelasticcollision
ciple,anonnegligible
componentisence”
forsynchrotron
thelabel]
lsyn
contribution,
exceptin theGHzregime[?
].
loducingatimeexpectedifparticles
canradiatebefore
s
✏
>
10
MeV,
electrons
wers,eWe
anddemonstrateless radiation
than fewinlength%thefor following
veryradinclined
aircooling
lengthsections that In
thisdeprinciple,
astrahlung
non negligible
synchrotron
component
isif
particles
canradiatebeforeundergoing
Bremhigh energy
particles.
At energies✏e > 10 MeV,
electrons,undergo
called“chargeinteraction,
i.e.,
for
l
/l
[12].
syn
rad
BremstrahlungeV,electrons
scription
breaksdown
for invery
inclined
air-showers,
reexpected
if particles can radiate
Brem2 before undergoing2
andpositrons
thethatcascadeundergoBremstrahlung
ons
from
the
air
emonstrateinthefollowing
sections
thisde3
3
1157 mi.e.,(to /Z)(✏e/l/88 MeV)
(B/50
µT)
interaction,
forwith/lexisting<length1,paradigm.
where
lXsyn
=believedngthlrada drastic= scattering,
Xi.e.,⇠lofsynradquiringrevision
the
0 /⇢
air
remstrahlung
strahlunginteraction,
for
l
<
1,
where
l
=
Historically,
synchrotron
radiationwasbeattenuation
l
=
/⇢
⇠
syn
rad
syn
rad
0
air
natingbreaksdown
air-showers,
rea netneg-for very inclined
2
2
2
1
2
2 2[14] is the 2 synchrotron
2 cooling lengt
1
3
3
1
X
=
36.7
g
cm
3.67
⇥
10
m
(⇢
/1
g
cm
)
,
where
X
=
36.7
g
cm
3
3
3
3
the
main
sourceoftheradio
emission(originallycoined33330=where
X
/⇢
⇠
air
0
1157
m
(
/Z)
(✏
/88
MeV)
(B/50
µT)
(⌫/80
MHz)
(B/50
µT) (⌫/80 MHz)
e
0 (✏
air
a,/Z)
drastic
revisionof the existing
paradigm.
e /88 MeV)
comparatively
derive(seealso [14]),
electronic
radiation length.
The produced
electrons
2 theelectrons
[14]
is
the
synchrotron
cooling
length. From this we“geosynchrotron”
emission).
IntheframeworkofverticalThe
produced=
36.7
g cm toand positrons
shown
hewas
synchrotron
cooling
length.
From
this
we
are also
deflected
by theshown
Earth(seemagnetic
derivealso [14]),
air-showers,
itwashowevertohavea negligible if
A.
Characteristicsofvery
inclined
air-showers
by
the
Earth
magnetic◆ 23 ⇣
ced
electrons
Synchrotron
emission
becomes
importantsion
forvertical
2 ✓
⇣
⌘
field
in
opposite
directions,with
Larmorradius
r
⇠
L
ee
also
[14]),✏e 2
B3
contribution,
except inµT)
the 1GHz
regime[? ].lsyn
4 inclined
Characteristicsofvery
air-showersthLarmorradiusr⇠✓◆
ry
inclinedair3.3
⇥
10
m
(✏
/100
MeV)(B/10
,
with
B
the
Earth
L
⇠
3.15
rth magnetic
e
2
1 ✓
⇣
⌘
⌘
the
synchrotron
cooling
lengthisshorterthantheinelasticcollision
length3 ⇣lsyn✏e⌫ 50 µT3
3
Indefineprinciple,
ainclined
non negligible
synchrotron
component
isB88 MeV
lrad
1 this study,
magnetic
field.
Inwevery
air-showers
as
µT)
,
with
B
the
Earth
⇠
3.15
radius rL ⇠ 2 expected
2
✓
◆
✓
◆
if
particles
canradiatebeforeundergoing
Breml
88
MeV
50 µT
80 MHz
1 kg
1
⇣
⌘
⇣
⌘
In
the
commonly
admitted
paradigm
ofradio
emisrad3
isstudy,
wedefinevery
inclined
air-showers
asthose
inducedbyprimary
particles
arrivingwithzenithns
that
thisde✏e sion3 strahlung
B interaction,
⌫ for
⇢
3
B the Earth
i.e.,
l
/l
<
1,
where
lsyn1=
byair-showers,
two
processes
account
for
most
of
syn
rad
duced
by ✓primaryparticles
arrivingwithzenithFigurerepresents the variation of15.
angles>75.
Cosmic-ray
air-showers
typicallyreach
air-showers,
re2
2
2
1
l
(B
)
<
l
(ρ
)
paradigm
of
radio
emis3
the
electromagnetic
signal.
The
major
process,
calledsynEarthrad11representsair
3 (✏ /88
3 (B/503
3
Figurethe variation
ofand
the ratio
lsyn/l✓rad
1157
( /Z)
MeV)
µT)
(⌫/80
MHz)
MeV“geomagnetic
50mµT
80
MHz
kg.m
>
7588
.maximumCosmic-ray
air-showers
typically
reach
e
as
a
function
of
⇢
hence
of
(E
paradigm.
theirlongitudinaldevelopment
aroundagramair
emission”,
isproducedbyelectronsandsesaccountfor
mostof
f mageradiolongitudinalasthatalength.
functionof⇢air andhence
of µT,✓ (Eq.
??),
fortypicalaximumaround2 a gram-cooling[14]
is 700
the gatsynchrotron
From
this
we
values
of
B
=
50
✏
=
88
MeV,
⌫=
ofemisXmaxpositrons⇠development
4002driftingcm.
We
assumetheethe front end of the shower, throughvalues of B = 50 µT,FIG.
✏ =1.88Characteristic
MeV, ⌫ = 80
MHz (to
(red
he
major
process,
called⇠ 400
700 gderivecm. We
assumethat thedeflection(seealsoof[14]),max
t Xairfor
mostofdecreases
lengths
besolid
updat
findthat a synchrotron
compthe competinge↵ectsmagnetic
particlelines).e We
densitywithaltitudefollowing the andLinslines).
We
findthat ence”
a synchrotron
component is expectedsity
decreases
withaltitudefollowing
Linsfor the label]
ducedbyelectrons
and1air-showers
represents
thevariationofthetheratiol/lscattering
mentioned
above,
andhence
producingatimerocess,calledsynradtocontributetotheof incline
ley
model
[13],
with
a
roughly
exponential
dependency.
◆ 23 ⇣ to the⌘emission◆emission
tocontributeofinclined
air-showers,
i.e.,
2 ✓
1 ✓
el
[13],
with
a
roughly
exponential
dependency.
⇣⌘
3varying
current
[11].
In
the
other
process,
called“chargedoftheshower,through
l
✏
B
⌫
⇢
3
3
syn
e
lsyn
/lrad
< 1,
for
⇢3 air
<
0.32
kg
m (✓
electronstion
of very
⇢and
and
hence
✓ mechanism,
(Eq.
??),
for
typicalHence
inclined
showers
developinthe upper
layair
l
/l
<
1,
for
⇢
<
0.32
kg
m
(✓
>
⇤
⇤
⇤
).
very
inclined
showers
inoftheupper
lay3.15
.
syn
rad
air
excess”developor ⇠“Askaryan”
electrons
from
the
air
FIG.
1. Characteristic
lengths(tobe updated).
3?? [”Incohericdeflection
andparticle[ExplainFig.
wherespace
the param
l
88
MeV
50
µT
80
MHz
1
kg.m
ers
of
the
atmosphere,
where
the
air
densityisparticHistorically,
synchrotron
radiationwa
ower,
throughrad[Explain
Fig. ?? where the parameterin B
heatmosphere,theair density
is particBair-showers= 50 µT,aswhere✏e =accumulate
88 MeV,
⌫=
80
MHz
(red
solid
atoms
inence”
theshowerfront,
creatinganet
negfor lengths
thelabel]
FIG.
1.
Characteristic(to[”Incohermain
sourceof theradio
emission(oandthenu
is thencovered.
and
then
reph
ularlylow.
Bygeometricalconstruction,
these
hence
producingatimeandnube
is updated).
covered.
andrephrase
next
paraByparticle
geometricalthese theshowersnow.
andativeconstruction,
charge excess along
shower core, showers
comparatively
ingwithzenithepagatefindthatasynchrotron
component
is
expected“geosynchrotron”
emission). In the 41
frame
ence”
for
the
label]
accordingly]
also
propagate
overlongerdistancesthanvertical
ones.
graph
accordingly]
to distances
theoutskirts.
latterones.
mechanism wasshown
tographover longer
than The
verticalr process,called“chargeSignature of coherence loss
Tests for 2 different BEarth values @GRAND/Auger sites, with ZHAiReS and CoREAS simulations
ZHAiReS, GRAND B eld

CoREAs, GRAND B eld

Auger B eld

Almost 1.5 order of magnitude cut-off in the signal for GRAND B eld!

fi

fi

fi

fi

fi

Almost no cut-off in the geomagnetic emission for Auger B eld

42

𝒪

Synchrotron signature: the clover-leaf patternv × v × B component: dominant contribution of Askaryan emission?

Projection of Efield on
vxvxB

[km]

Expected pattern

Observed pattern: clover-leaf[km]

ZHAireS[km]

CoREAS (85 degree)

New polarization signature on thev × v × B component!
• ~ 10% of the total emission forinclined showers• Observed in simulations for the
3.4-4.2 GHz band only here (100 MHz)[km]

(Huege 2013, CROME data)

Clover-leaf pattern: hints for a third type of emission dominant over the
charge excess for inclined EAS

43The clover-leaf pattern: hints of a synchrotron emission
Simulation of an e +/− pair in a uniform B eld with Corsika8
Particles with same energy, starting vertically downwards, observer on the symmetry axis

Clover-leaf pattern[km]

Synchrotron predictions

Credits to Nikolaos Karastathis

[km]

fi

Synchrotron emission of an e +/− pair leads to a clover-leaf
like polarization pattern!
44

slide adapted from S. Chiche

New signatures in the radio signal!
Signal cut-off

Clover-leaf pattern
CoREAs,Auger B eld

ZHAiReS,
GRAND B eld

1.5 orders ofmagnitude!

Linked to a loss of coherence

Linked to synchrotron radiation

Geomagnetic + Askaryan description no longer valid
for very inclined air-showers
Could strongly affect detection strategies of future experiments
Could help for cosmic-ray/neutrino discriminationfi

fi

Simon Chiche, Zhang, KK, Huege, de Vries, Prunet, Schlüter, Tueros, in prep.
Marion Guelfand, Simon Chiche, KK, Prunet, in prep.45