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The Tianshan Radio Experiment for Neutrino Detectio n

The Tianshan Radio Experiment for Neutrino Detectio n. Olivier Martineau-Huynh NAOC G&C lunch talk May 28, 2014. Milky Way over 21CM array ( Gu Junhua ). Physics with UHE cosmic neutrinos. UHE neutrinos as a tool to study violent phenomena in the Universe

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The Tianshan Radio Experiment for Neutrino Detectio n

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  1. The Tianshan Radio Experiment for Neutrino Detection Olivier Martineau-Huynh NAOC G&C lunch talk May 28, 2014 MilkyWay over 21CM array (GuJunhua)

  2. Physicswith UHE cosmic neutrinos • UHE neutrinos as a tool to study violent phenomena in the Universe • One example: youngextragalactic pulsars (Ke Fang et al., arXiv:1311.2044) • UHE heavynucleiemmited (= UHECRs) • Interaction with supernova ejecta • p+ l +nl(= UHE neutrinos)

  3. Physicswith UHE cosmic neutrinos • GZK neutrinos p+gCMB D+p+ + n. p+ l +nl. Great tool to studyUHECRs. GZK suppression? Ahlers et al., arxiv:1208.4181

  4. Physicswith UHE cosmic neutrinos • Lots of physicswith neutrinos above 1016eV • Test of pulsars, AGN, GRBs, • Test of UHECRs propagation • Probe distant Universe • … • Downside: neutrino detection challenge + low flux @ UHE… Need for cheap / scalable /easilymaintainabledetector.

  5. Neutrino detection • Elusive particle requires dense & large target: • Ice: detection of showerinitiated by n NC interaction • Ground ARIANA project 1400m ICECUBE 1000m

  6. Birth of neutrino astronomy • IceCube2012&2013 • Milestone in astronomy&astrophysics but: • Angularreconstruction for showerevents? • ~1 event/yearabove250TeV.

  7. Neutrino detection nt t Target = Earth Extensive air shower Radio detection Eth ~1017 eV • Earth + mountains as target for neutrino interaction (AUGER-type) • Radio detection of subsequent EAS (good at large zenith angles)

  8. Bgeo  F = qvBgeo - + EAS radiodetection: principle • Acceleration of relativistic charged particles in the Earth magnetic field (Kahn & Lerche, 1965): geosynchrotron emission Bgeo  • Coherent effect • detectable radio emission • (~100ns & 10s µV/m)

  9. Giant Radio Array for Neutrino Detection • 100’000 antennas over 60’000km² wouldmake the best UHE neutrino observatory. (sensitivityevaluation TBC by full MC) • Major challenge: n identification over background The GRAND project Esh=1018eV q=90° 472 antennastriggered

  10. Radio background TREND-50 antennas radio array: - 1.5km² - 220 days data subset - 1.2 1010 triggers recorded - 1.4 109coincidences ~0.2Hz eventrate over TREND-50 array (physicalorigin) Expected EAS trigger rate: ~100 events/day for E>1017 eV TREND antenna Reconstrcuted source position Background rejection is a key issue for EAS radio-detection. Background sources: HV lines, radio emiters, train, cars, planes, thunderstorms…

  11. Autonomous EAS radio-detectionwith the TREND-50 setup • 50 antennasdeployedin summer-automn 2010, total surface ~1.5km². • Stable operationsinceJanuary 2011. • Goal: establishpossibility for autonomous radio detection of EAS. TREND-15 (2010) TREND-50 ~1.5 km²

  12. Background rejection • Background: • Close source: • - Sphericalwavefront • Fast drop of amplitude whenmoving • awayfrom source. • Distant source: • ~ Plane wavefront • ~ Constant amplitude • Both: correlated in time & direction. • EAS signal • ~ Plane wavefront. • Fast drop of amplitude whenmovingawayfromshower axis. • Random time and direction Shower axis Radio cone EAS signal Background

  13. TREND-50 EAS candidates EAS simulation Proton showers @ 1017eV (halfsky) 2011-2012 data (Antennasoriented EW): 396 candidates in 320 live days. 90° 90° 60° 60° 30° 30° West 90° West 90° South 90° South 90°

  14. TREND-50 EAS candidates Data (norm) Simu (norm) • Good match between data & EAS simulation: • TREND-50 was able to identify EAS withlimited background contamination. • Still a preliminaryresult: • Simulation statistics to beincreased. • Analysiscuts to beapplied to simulated data. • If theyremain, discepencies to beunderstood (e.g. large q values) Data (norm) Simu (norm)

  15. n - inducedshowerradiodetection • Identification of standard EAS OK statistically (TREND-50). • Neutrino detection: • Verybad Signal/Noise ratio: TREND-50 ID method not reliableenough. • Looking for horizontal showers: amplitude pattern at groundnot as specific as for standard ones Shower axis Shower axis Standard EAS signal: focusedgroundpatern & rapid drop of amplitude n-induced (~horizontal) shower: no significant variation of amplitude alongshower axis (but OK in lateral direction)

  16. Polarizationmeasurment • EAS radio emissionispolarized: at first orderF = qv.Bgeo Linearpolarity, withP Bgeo & P shower direction Showercore (q=66°, j = 354°) z b ~89° on all antennas h ~7° on all antennas b P x h Trigerredantennas y

  17. GRAND-proto • Polarizationmeasurment = powerfull identification tool for EAS? • Test setup: «GRAND-proto» • 35 3-polar antennasfor a complete polar measurment (h = atan(Vy/Vx) & b = atan(Vz/Vplan). • 6 antennas in test at present. • 21 scintillators for EAS offline validation (IHEP) • Full setup in summer 2015.

  18. Conclusion • Neutrinos are a powerfulltool for astrophysics (violent phenomena multi-messengerapproach) • Giant radio arrayscouldbe the mostadequate instrument for theirdetection. • Main challenge: background rejection • TREND-50 results (very) encouraging, GRAND-proto promising!

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