The TIANSHAN RADIO EXPERIMENT FOR NEUTRINO DETECTION:

an autonomous radio-array for air showers detection

Olivier Martineau-Huynh IHEP, 17/02/2011

IHEP (Hu HongBo, Gou QuanBu, Zhang Jilong, Zhang Yi & Olivier Martineau-Huynh)IN2P3 (Ardouin, Carloganu, Charrier, Lautridou, Martineau-Huynh, Niess, Ravel) NAOC (Thomas Saugrin, Wu XiangPing, Zhao Meng)

Radio detection of EAS

Bgeo

e+e-

F = qvBgeo

• Acceleration of relativistic charged particles in the Earth magnetic field (Kahn & Lerche, 1965): geosynchrotron emission

• Coherent effect

detectable radio emission

LOPES: H. Falcke et al., Nature 435 (2005)CODALEMA:D. Ardouin et al., NIM A 555 (2005)D. Ardouin et al., Astro. Phys. 31 (2009)

Radio detection of EAS• Why radio?–Measurement of direction of origin, energy (?),

nature of primary (??)– Easiness of deployment & cost!

15k€/unit

3 tons

<1k€/unit (?)

<10kg (?)

Radio detection of EAS

• Only 2 established setups –<30 antennas: low stat– Slave-triggered to standards EAS detectors

Still a long way ahead!!!

Self-triggering?

Amplitude lateral profile?

Energy measurment?

Primary nature determination?

Threshold?

The TREND site

• Ulastai, Tianshan mountains, XinJiang autonomous province (2650m asl)

Beijing

Urumqi

Ulastai

The electromagnetic environementVery clean radio

environement above 20MHz.

AM emitters

AM emitters FM emittersTREND

@ Ulastai

CODALEMA@ Nançay

The 21cm arraya radio-interferometer for the study of the

Epoch of Reionization (Wu XiangPing, NAOC)

EastWest

North

SouthDAQ

4 km

3 km

127 log periodical antennas

x 80 pods

along 2

baselines

TREND prototype (2009)N

E

S

W

21CMA pods

TREND antenna

First tests on site in June 2008. 6-antennas prototype running in January 2009.

N

TREND prototype setup

podDAQ room200MSamples/

s ADC+CPU+dis

k

optical fiber

84

dB

50-200MHz filter

21CMA acquisition

optical fiber

64

dB

50-100MHz filter

TREND acquisition

TREND prototype performances

• Reconstruction performances

N

- static source (a car inside the array)

ΔSN~1.6 m & ΔWE~1.5 m

4-antennas events5-antennas events6-antennas events

spherical wave analysis

TREND prototype performances

• Reconstruction performances : plane track

4-antennass = 8°

5-antennass = 5°

6-antennass = 2°

TREND antenna sensitivity

Major radio source: thermal emission from the Galactic plane.

Visible in Ulastai sky between 15h & 23h LST.

Galactic plane @ 408MHz

CRs@21CMATREND antennas clearly exhibit an increased noise level when the Galactic plane is in the sky

Local sideral time

Sig

nal nois

e level

TREND EAS search

• Discrimination of EAS from RF background

- short/symmetrical/isolated pulses

- in general, longer & repetitive pulses

- random time & direction of arrivals

- in general, localized sources or tracks

- ~plane wave front

- exponential decrease for lateral amplitude profile

- spherical wave front

- 1/distance decrease for lateral amplitude profile

Background signalsCR signals

Time [mn]

Azi

muth

[d

eg]

TREND EAS searchNoisy periods rejection

• Select quiet periods (<3evts/3mins)• 69% of 6-antennas prototype data (403h)

TREND EAS search

«Quiet» periods data: 2259 events in 403 hours

Select events with q<65° only.

TREND EAS search

• 3 additionnal cuts 25 EAS candidates

2.1s excess towards North (20/25 events)

CODALEMA

Bgeo

see Astropart Phys paper:

arXiv:1007.4359

EAS shower reconstruction

Shower core position & lateral distribution could be reconstructed for 18 candidates. Not totaly reliable as no satysfying amplitude calibration performed so far.

TREND 2nd phase (2010)

• 15 antennas • 3 scintillators :

ground array for EAS detection cross-check

Scintillator array• 50cmx50cmx2cm

plastic scintillator + PMT

• PMT signal directly fed into optical transmiter (20-200MHz)

• Independent trigger for all 15+3 detectors

• Scintillator threshold set for ∼25Hz individual trigger rate. time [μs]

Scintillator data

• 620 3-fold coincidences found in 19 days of scintillators’data.

The 3-scintillators array is a valid EAS

detector

Radio data

• Selection of ~15 EAS candidates within the 19 live days (applying selection procedure defined with the prototype)

Hybrid coincidences

• 3 events with 4+ antennas & 3 scintillators in coincidence

• 2 events with 4+ antennas & 2 scintillators in coincidence

Hybrid coincidences• Random coincidences?

• Triggers on PMT signals?– Trigger delays not consistent with expected

propagation times.– For 4 hybrid coincs (out of 5), some antennas

triggered before the scintillators.

Expected rate for 2 independent events given by:

fA = 1.6 10-4 Hz rate of 3-folds scintillator eventsfB < 10 Hz rate of radio events (multiplicity≥4)Δt = 2 µs

frdm = 2*fA*fB/(fA+fB)*(1-exp(-(fA+fB)Δt)) Hz

frdm = 0.1/year...

No!

No!

Hybrid coincidences• Independent reconstruction

for 3 hybrid coincs with 3 scints

Radio recons

Scint recons

CoincAΘ= 52±1°

φ =195±1°

Θ= 49±3° φ

=191±4°

CoincBΘ= 61±3°

φ =359±2°

Θ= 67±5° φ =3±4°

CoincCΘ= 42±1°

φ =55°±4°

Θ= 36±3° φ =56°±5°

Coincidence A

First autonomous radio-detection of EAS!(see Astropart Phys paper: arXiv:1007.4359)

TREND 3rd phase (2011)• 50 antennas (1.1 km²):

largest EAS radio-detection setup

Numerous EAS candidates expected!Lots of analysis work and physics ahead.

Next steps

• Improve setup:– Faster ADC (500MHz)– Front end digitization– 2nd level trigger– Upgrade optical

transmetters & receivers

– Move to 20-100MHz frequency range (?)

Need for financial support & expertise!

Next steps• A hybrid detector?– 24 scintillators (?) for full ground array– Energy calibration, shower reconstruction

comparison, lateral profile studies…– Complementary (?) to CODALEMA & AERA– Financial support?

TREND long term perspectiveHigh energy neutrinos detection through tau production in rock and decay in atmosphere

ntt

Neutrino detection at TREND

• High mountains:– Additional target for

n– Screen for CR

showers

• Environment: few RFI sources+very little thunder activity

• Radio optimal for inclined showers detection (?)

UlastaiTREND

Detection cross sections

En = 1016 eVAveraged over f

En = 1018 eVAveraged over f

TREND site topologyFlat site (close showers)

TREND site topologyFlat site (close showers) Upward going Downward going

Upward going Downward going

Neutrinos flux limit

TRENDAUGER (PRD 2009)

AUGER integrated

AUGER integrated

Waxmann-Bahcall limit

90%CL limitassuming flux f=f0/E2 and no candidate within 4 years (& 0 background

expected)

Results obtained with optimistic

hypothesis. To be confirmed with final antenna design + radio simulation

Antenna R&D

• Design for optimal sensitivity along horizon? – On-going work– On-site tests foreseen in 2011

Conclusion

• TREND project running since 2008.• Autonomous radio detection of EAS

established (arxiv:2010.4359).• At present largest setup for EAS

radiodetection. Attractive physics soon to come!

• System upgrading foreseen (electronics+ ground array?)

• Neutrino search late 2012? (new antenna design)

谢谢  !Thank you !