Low frequency observation of cosmic-ray air-shower radio emission - - PowerPoint PPT Presentation

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Low frequency observation of cosmic-ray air-shower radio emission - - PowerPoint PPT Presentation

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Low frequency observation of cosmic-ray air-shower radio emission by EXTASIS Antony Escudie et. al Subatech IMTA / CNRS / Universit de Nantes 18/07/2017 - CRI102 What ? Low frequency detection What ? Low frequency detection Radio

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Low frequency observation of cosmic-ray air-shower radio emission by EXTASIS

Antony Escudie et. al

Subatech – IMTA / CNRS / Université de Nantes

18/07/2017 - CRI102

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ICRC2017, Bexco, Busan, Korea Antony Escudie 2

What ? Low frequency detection What ? Low frequency detection

  • Radio emission from kHz up to GHz
  • Commonly used band [30-80] MHz

(CODALEMA, AERA, LOFAR, TREND, Tunka-Rex, Yakutsk)

  • Low frequency (LF): no current

experiment until now < 10 MHz

  • Expected signal from shower

development (geomagnetic + charge excess) + « sudden death » signal

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ICRC2017, Bexco, Busan, Korea Antony Escudie 3

Why ? New signal Why ? New signal

Talk from D. García-Fernández-CRI103

[arXiv:1307.5673] [arXiv:1211.3305]

SELFAS

Proton 1017 eV Vertical shower dantenna=300 m For Nançay site

Electric field in vertical polarization

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ICRC2017, Bexco, Busan, Korea Antony Escudie 4

Why ? Larger detection range Why ? Larger detection range

[30-80] MHz [10-30] MHz [5-10] MHz [1-5] MHz

Simulated footprints of electric field for different frequency bands Limited detection range in classical band [30-80] MHz Larger at low frequencies (<5 MHz) (sparse, cost effective array)

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ICRC2017, Bexco, Busan, Korea Antony Escudie 5

How ? New antennas How ? New antennas

Poster from B. Revenu-CRI109 board#47

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ICRC2017, Bexco, Busan, Korea Antony Escudie 6

How ? How ?

9m height Regular Butterfly antennas with a modified LNA for [1-10] MHz Externally triggered by scintillators

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ICRC2017, Bexco, Busan, Korea Antony Escudie 7

Environment and sky Environment and sky

Night Day

Dominated by man-made and atmospheric noise Atmospheric noise lower during day than during night duty cycle ~ 50% ⇒

  • D. Charrier

Analysis band 1 2 3 4 5 7 8 9 10 Sunrise Sunset

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Preliminary results

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ICRC2017, Bexco, Busan, Korea Antony Escudie 9

Low frequency events (I) Low frequency events (I)

Arrival direction reconstructions:

 ϴSA=60°, ϕSA=153°  ϴSC=61°, ϕSC=154°  ϴLF=66°, ϕLF=155°

  • We see atmospheric air showers at low frequency ([1.7-3.7] MHz)
  • Detection range seems indeed larger at low frequency

Traces after filtering + LPC processing

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ICRC2017, Bexco, Busan, Korea Antony Escudie 10

Low frequency events (II) Low frequency events (II)

Reconstructed shower core

Traces after filtering + LPC processing Arrival direction reconstructions:

 ϴSA=41°, ϕSA=145°  ϴSC=32°, ϕSC=144°  ϴLF=31°, ϕLF=146°

SELFAS reconstruction (radio):

 estimated shower core : x=260 m, y=-810 m  estimated Xmax=710 g/cm²  estimated energie: 3,6.1018 eV

Scintillators reconstruction (radio core):

 estimated energie: 2,8.1018 eV

  • L. Martin, in proceedings of this conference
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ICRC2017, Bexco, Busan, Korea Antony Escudie 11

Low frequency events (II) Low frequency events (II)

[30-80] MHz [10-30] MHz [5-10] MHz [1-5] MHz

PE antenna: 850 m

  • nly LF

⇒

QH antenna: 620 m

  • nly LF

⇒

HL antenna: 640 m

  • nly LF

⇒

LQ antenna: 180 m ⇒ HF & LF

Reconstructed shower core

SELFAS

LQ HL PE QH

Larger detection range at low frequency

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ICRC2017, Bexco, Busan, Korea Antony Escudie 12

Conclusion & Outlook Conclusion & Outlook

 LF antenna operational: low frequency events seen (agreement

between the different arrival direction reconstructions & low rate of random signals)

 Larger detection range at low frequency than at high frequency  Complete analysis is underway...  Still waiting for the sudden death signal (high energy, vertical shower)

V e r t i c a l p

  • l

a r i z a t i

  • n
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Thank you for listening !

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Back-up slides Back-up slides

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ICRC2017, Bexco, Busan, Korea Antony Escudie 15

Radio emission of Extensive Air Showers Radio emission of Extensive Air Showers

[30-300] MHz [0.3-3] GHz [3-30] MHz [3-3000] kHz

AERA, CODALEMA, LOPES, LOFAR... Pioneers of the 70s up to 90s EASRADIO, Akeno, AGASA...

 Strong electric field and signal measured very far-away…

(Allan, Clay, Hough, Pidcock, Prescott, Stubbs...)

 …but detection limited by atmospheric noise and artificial

emitters

 Secondary charged particles hit the ground

strong low- ⇒ frequency radio emission measured far away from the ⇒ impact point, linked to the remnants of the shower ⇒ « Sudden death » ~6000 events

 Geomagnetic  Charge excess

Few events

 Transition radiation  Other mechanism ?

EXTASIS project

ν

L.Martin this afternoon B.Revenu, poster D.García-Fernández for a theoretical approach Too much emitters

ANITA,CROME, MIDAS, AMBER, EASIER...

~50 events

 Geomagnetic  Charge excess  Cherenkov

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ICRC2017, Bexco, Busan, Korea Antony Escudie 16

Radio detection optimization Radio detection optimization

Detection range in classical band [30-80] MHz too small

SELFAS

Proton 1017 eV Vertical shower dantenna=300 m

Look at low frequency:

  • Better detection range (sparse, cost effective array)
  • New mechanism in simulations: «sudden death»

(D. García-Fernández-CRI103)

  • Precise core position determination, absolute time scale of the shower

(B. Revenu-board #047)

SELFAS

1 10 100 (MHz) 2 5 30 80

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ICRC2017, Bexco, Busan, Korea Antony Escudie 17

LF antennas LF antennas

Externally triggered by the scintjllators Butuerfmy antennas, East-West and Vertjcal polarizatjons, on a 9 m mast Actjve antenna with adapted LONAMOS (D.Charrier) low noise amplifjer to the band [2 − 6] MHz LONAMOS LNA

TRIGGER

selectjon

OSCILLOSCOPE

digitatjon

GPS

tjming

COMPUTER

recording evt Acquisitjon system

2 cabled antennas 5 network-connected antennas

  • D. Charrier
  • D. Charrier
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ICRC2017, Bexco, Busan, Korea Antony Escudie 18

How ? How ?

Objective:

  • observed a pulse in the associated CODALEMA HF
  • observed the same pulse in the EXTASIS HF
  • use the timing of the pulse to find it in the EXTASIS LF

(make sure that we observe “shower” signal)

EXTASIS LF [1-5] MHZ EXTASIS HF [20-250] MHz CODALEMA HF [20-200] MHz Externally triggered by scintillators Self-triggered

EXTASIS apparatus

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ICRC2017, Bexco, Busan, Korea Antony Escudie 19

Low frequency events 1 Low frequency events 1

Traces after LPC processing LF HF Filtered traces

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ICRC2017, Bexco, Busan, Korea Antony Escudie 20

Short overview of low frequency studies Short overview of low frequency studies

Strong electric field and signal measured very far-away ... … but detection limited by atmospheric noise and artificial emitters

Secondary charged particles hit the ground strong low-frequency ⇒ radio emission measured far away ⇒ from the impact point, linked to the remnants of the shower ⇒ « Sudden death »

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ICRC2017, Bexco, Busan, Korea Antony Escudie 21

  • B. Revenu
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ICRC2017, Bexco, Busan, Korea Antony Escudie 22

  • For E > 1016 eV: 0.5 shower per km² per str and per min
  • Divide by 128 for each decade => 2.5 10-5 shower per km² per str

and per min for E = 1018 eV

  • At Nançay, 1 km² => 0.2 shower with E = 1018 eV per day

=> So, few events at 1018 eV per month

Event rate at Nançay Event rate at Nançay

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ICRC2017, Bexco, Busan, Korea Antony Escudie 23

1.7 3.7

Linear predictive coding Linear predictive coding

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ICRC2017, Bexco, Busan, Korea Antony Escudie 24

Daily variation of ionosphere layers Daily variation of ionosphere layers

D 45–55 miles E 65–75 miles F1 90–120 miles F2 200 miles (50–95 miles thick) Properties ionosphere: function of the free electron density

⇒ altitude, latitude, season, and primarily solar conditions

D and E bands disappear at night and F1 and F2 combine D layer: absorbs and attenuates RF from 0.3 to 4 MHz. Below 300 kHz, RF above 4 MHz will be passed unaffected. The D layer is present during daylight and dissipates rapidly after dark. The E layer will either reflect or refract most RF and also disappears after sunset. The F layer is responsible for most sky-wave propagation (reflection and refraction) after dark.

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ICRC2017, Bexco, Busan, Korea Antony Escudie 25

LF antenna environment LF antenna environment

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ICRC2017, Bexco, Busan, Korea Antony Escudie 26

Coincidence at Nançay Coincidence at Nançay

Per month :

  • Few millions of L1 triggers per autonomous station
  • ~ 40,000 events for the scintillators
  • ~ 40,000 for the LF antennas (externally triggered…)

Build of coincidence between SA and SC :

  • Only ~60 coincidences remaining !

Build of coincidence between SA, SC and LF :

  • Only 1 coincidence per month since April, 2017

Probably more events if we build only coincidences between SC and LF: detection range larger at LF, so maybe some LF events exist in our database without a coincidence with the SA ! Work in progress...