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Radio Detection of High Energy Showers

). Radio Detection of High Energy Showers. Sylvie Dagoret-Campagne GDR Neutrinos, IPN, October, 4 2006. History of radio detection of Air Showers. Started with Jelley in 1964. But decoherence Appears as frequency increases Spencer (1969) and Allan (1971).

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Radio Detection of High Energy Showers

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  1. ) Radio Detection of High Energy Showers Sylvie Dagoret-Campagne GDR Neutrinos, IPN, October, 4 2006

  2. History of radio detection of Air Showers • Started with Jelley in 1964 But decoherence Appears as frequency increases Spencer (1969) and Allan (1971) Measure by Vernov at al. (1968) Indicating coherence Within a given frequency band GDR Neutrinos, 4-5 october

  3. What can we conclude from a Radio Lateral density Function (RLDF) • Dependence with • Frequency, • Incident angle, • Relation to primary energy ? Allan,H.R, Havera Park (44 MHz,60MHz) ? From Allan (1971) Frequency at 55MHz Normalised pulses For 1017eV<E<1019eV θ<30° GDR Neutrinos, 4-5 october

  4. Main questions still open • Can Radio detection measure the Shower energy ? • Can Radio detection identify the nature of the Cosmic rays ? • In the 70’s Radio detection where abandoned in favour of • Particle detection at the ground (scintillators or Cerenkov water rank), • Then Cerenkov emission was used (pointing on identified photon sources) • Later in the 90’s the Fluorescence detection was used. GDR Neutrinos, 4-5 october

  5. Content • Usual detection method of Air Showers • Radio emission process • Cerenkov emission, • Synchrotron emission, • Bremstrahlung emission, • Transition radiation, • Radar detection • The question of the coherence, • Current experiment in radio detection • Radio Cerenkov experiments for neutrino detection, • Air Shower Radio detection, • Test beam experiments that should be done • Radio « detectors» GDR Neutrinos, 4-5 october

  6. Usual techniques of Air Shower detection GDR Neutrinos, 4-5 october

  7. Rm: Moliere Radius Shower development Gaisser Hillas Shower Scaling parameters: • In Air: • Rm(asl)=70m • In Ice: • ρ=0.9g/cm3 • Rm=13cm • Latt(ν)=100m-1km • n=1.3 - 1.8 • In Rock Salt: • ρ=2g/cm3 • Rm= • Latt(ν)~250m-1km • n=2.45 • Lunar regolith (10-20 m depth) • ρ=1.7g/cm3 • Latt(1GHz)=20m • n=1.7 Vertical Air Shower(1019eV) Vertical Air Shower(1019eV) Nishimura Kamata Greisen GDR Neutrinos, 4-5 october

  8. Loss of coherence Radiation of electromagnetic wave by a charged particle • Generic solution from retarded potentials • Fourier transform of the radiative part 1019 eV Shower in Bearth Radiative part TF GDR Neutrinos, 4-5 october

  9. Charged Particle Energy loss rate • Ionisation losses of electrons • Cerenkov energy loss • Acceleration energy loss (air) Fluorescence Yield ~ 4 γ/MeV@ 337nm => energetic Yield ~ 10-5 Cerenkov may Not be neglected In air GDR Neutrinos, 4-5 october

  10. Example of Radio Cerenkov emission in dense media • Detected signal in Ice at a given distance (100 m or 500 m) • Not the same slope vs • Shower energy because coherence appears for radio signal • Srf ~ Nelec2 (coherence, • for (λ>RM)) • Sopt ~ Nelec (no coherence, for (λ<RM))) GDR Neutrinos, 4-5 october

  11. Cerenkov emission in Showers In a track step of constant β for a single particle: (Zas,Hazen, Stanev parameterisation) Contribution inside a Shower : • Need charge excess 20 – 30 %: • Compton scattering, • δ rays production, • Positron annihilation, • (Akarian effect) The electric field is linearly polarised. GDR Neutrinos, 4-5 october

  12. Frequency dependence : coherence- decoherence transition observed for Cerenkov emission in salt A0=2.53x10-7 V/MHz fd=0.52; δ=1.44 ν0=1.15 GHz ν1=2.86 GHz empirical parameterisation: hep-ex/0602043 (SLAC test beam) GDR Neutrinos, 4-5 october

  13. Application of Cerenkov emission in dense Media to High Energy Cosmic Neutrinos I GDR Neutrinos, 4-5 october

  14. Radio emission detectors (Antenna and Horns) dedicated to neutrino shower detection (US) FORTE 97-99 ν shower detection in Greenland Ice Log periodic antenna, 20-300 MHz A=105 km2.sr GLUE/Goldstone 99: ν shower detection In Lunar regolith L and S band (about 2 GHz) A=6.105 km2.sr ANITA: End 2006 ν shower detection In Antartica Ice 200 MHz - 1.2 GHz A=104 km2.sr GDR Neutrinos, 4-5 october

  15. Application of Cerenkov emission of ν induced Showers in Ice or atmopshere:Pioneering radio experiments (FORTE) GDR Neutrinos, 4-5 october

  16. Example of Forte neutrino candidate Background: one frequency Long duration. Signal : wide band, during few ns Frequency channel time GDR Neutrinos, 4-5 october

  17. Application of Cerenkov emission in the Lunar Regolith to detect High Energy Cosmic Neutrinos Target volume for radio detection: 2 x 105 (km.w.e )3 GDR Neutrinos, 4-5 october

  18. GDR Neutrinos, 4-5 october

  19. Application of Cerenkov emission of ν induced Showers in Ice : The anita Concept GDR Neutrinos, 4-5 october

  20. SALSA GDR Neutrinos, 4-5 october

  21. Salsita: 4 strings • 3 events per year Existing Neutrino Limits and Potential Future Sensitivity • RICE limits for 3500 hours livetime • GLUE limits123 hours livetime • ANITA sensitivity, 45 days total: • ~5 to 30 GZK neutrinos • IceCube: high energy cascades • ~1.5-3 GZK events in 3 years • Auger: Tau neutrino decay events • ~1 GZK event per year? • SalSA sensitivity, 3 yrs live • 70-230 GZK neutrino events Salsita 3 years GDR Neutrinos, 4-5 october

  22. Geo Synchrotron process in AirShowers single particle-> Formula used in particle Shower Monte Carlo like Aires GDR Neutrinos, 4-5 october

  23. Radio emission detectors (Antenna and Horns at ground) Codalema dipole (Nancay) Lopes V antenna (KASCADE) Codalema log periodic Antenna (Nancay) AMBER Horn (Hawai) GDR Neutrinos, 4-5 october

  24. Codalema • What is the Radio LDF ? • dependence on incident angles • Frequency dependence • Antenna directivity • Relation to energy (coherence) GDR Neutrinos, 4-5 october

  25. Molecular Bremstrahlung • Microwave Molecular Bremsstrahlung Radiation (MBR) in EAS • Only a small fraction of the available energy budget for secondary isotropic radiation is used up by optical fluorescence. • MBR is simply a subsequent radiative process resulting from the cooling of the EAS plasma. • The minimum MBR flux can be calculated by considering the emissivity and absorption of a classical bremsstrahlung process. • This process contains a suppression term: Plasma Emissivity: GDR Neutrinos, 4-5 october

  26. Principe de détection Radar • Illuminer les gerbes avec un faisceau radar • Coïncidence détecteur au sol / signal radar • Gerbes horizontales (standard a haute altitude, neutrinos a basses altitudes) GDR Neutrinos, 4-5 october

  27. Radar detection principle GDR Neutrinos, 4-5 october

  28. Possibility to measure the longitudinal profile with radar cross section measurement Ionisation profile density (Aires) Detection threshold: The measure of the RCS gives the Fourier transform of the ionised electron density It is proportional to |ne(r)d3r|2 At low frequency σT=0.665x10-24cm2 GDR Neutrinos, 4-5 october

  29. Calculs de Section efficaces Radar de gerbes (provenant de la première zone de Fresnel) (P. Gorham,2001) • La section efficace a un profil approximativement gaussien de FWHW ~ 30° 10 Mhz 30 Mhz 50 Mhz angle radar GDR Neutrinos, 4-5 october

  30. Ionised electron life time measurement • The electron lifetime at a few km of altitude constrains the possibility of the radar detection of vertical showers • This electron lifetime measurement must be checked/measured in a test beam GDR Neutrinos, 4-5 october

  31. Radar routinely used for Meteor detection (from H. Takai, ANL and Brookhaven) Small, overdense meteor, of approximately 0.8s duration. One long and two small underdense meteors. ~ 500 km Data taken with 67.26 MHz (ch 4) - Pittsburgh Station GDR Neutrinos, 4-5 october

  32. Simple Cheap Radar Detection System ANL and Brookhaven groups Reflected TV signals from meteors, airplanes, … “Homemade” Dipole Antenna (or any TV antenna) Commercial Radio Receiver GDR Neutrinos, 4-5 october

  33. Frequency Spectrum vs Time in Argonne System: Airplanes and Meteors Meteors Airplanes Time Frequency GDR Neutrinos, 4-5 october

  34. Now proof must establish the connection of Air Shower detection with short time (few ns) Radar echo GDR Neutrinos, 4-5 october

  35. Test Beams to validate Radio detection principles, to prove coherence principe • Cerenkov Coherence (Askarian principle) • Used for Neutrino Radio detection • Geo-Synchotron Coherence/incoherence • Used in Air Shower detection • Molecular Bremstrahlung • Contribution to Air Shower detection • Transition Radiation • Contribution to Air Shower detection • Radar detection GDR Neutrinos, 4-5 october

  36. Validation of Askarian effect Coherent Radio Cerenkovin sand and salt Proof of coherence?Must show a frequency Cutoff ! NIM A490 (2002) 476 astro-ph/0412128 GDR Neutrinos, 4-5 october

  37. Molecular Bremstrahlung GDR Neutrinos, 4-5 october

  38. Search of Molecular Bremstrahlung at SLAC Proof of coherence ? Measure of e lifetime ? 60 ns ? GDR Neutrinos, 4-5 october

  39. Tests in an electron Beam we would like to do at LAL or IPN to check the Radio emission • Check of Coherence in Synchrotron emission in a dipole magnetic field, • Coherence never clearly established neither in a circular nor linear accelerator • Correction for Transition radiation backscattered at ground ? • Check the molecular bremstrahlung and measure the electron lifetime in the ionised plasma, • Check results from SLAC test beam results • Detect the radar echo of the electron beam, • Predicted since a long time, never proved, • Calibrate our instrumentation using Cerenkov emission in a dense material • (coherence assumed at these frequency) VHF measure are quite unusual in HEP experiments, Benefit from new technologies (Fast Oscilloscope, FADC above GHZ) GDR Neutrinos, 4-5 october

  40. 1.Test de l’existence du Bremstrahlung Moleculaire Taille du faisceau variable • Le passage des electrons dans l’air cree un plasma, • Les electrons ionises du Plasma induisent une emission RF appelee bremstrahlung thermique (en astro) ou moleculaire. • Le but est de mesurer la duree de vie de colonne d’ionisation, voir de verifier sa densite spectrale d’emission. 0.20m 1m antenne GDR Neutrinos, 4-5 october

  41. Antenne monitoring Taille du faisceau variable 0.20m Chambre non métallique pour faire varier la pression 1m Faisceau radar Antenne réceptrice 2.Test de la diffusion radar • Le passage des electrons dans l’air cree un plasma • On essaye de determiner la duree de vie des electrons du plasma en etudiant la forme temporelle de l’echo radar. • On mesure la section efficace de diffusion Radar GDR Neutrinos, 4-5 october

  42. Dipole magnétique (10-100 Gauss) Electron 10 MeV Photon synchrotron détecteur 3m 5m 3.Test de coherence sur le rayonnement synchrotron • B=10 G (20 x Bterre) • Ecrit=1.1 10-4γe2 B(T) = 4.5.10-5 eV • Rcurv= 3E(GeV)/B(T) =30m • νcrit=67GHz • λcrit=4.5mm GDR Neutrinos, 4-5 october

  43. Radio Synchrotron spectrum that should be measured with its coherence /decoherence transition Coherence never really established At which frequency this transition occurs ? Contribution of beam sub-structures ? GDR Neutrinos, 4-5 october

  44. Conclusion • There is a wide interest to detect Showers with radio : • 100 % duty cycle (10 x Fluorescence aperture) • Antenna may be cheaper than Photomultipliers, • Larger acceptance for neutrino detection due to longer attenuation range, • But one has to prove we can do Air shower measurement with RF as well as standard techniques: • Energy measurement, • Primary identification, • Some fundamental questions must be answered like, • Main physical processes involved in radio emission by shower electrons, Cerenkov radiation, Transition radiation, Synchrotron, • Ionised plasma physics vs altitude and atmospheric composition, atmospheric condtions (p,T) must be understood, (Bremstrahlung,Radar) • Coherence effect vs frequency, • Calibration techniques must be found, GDR Neutrinos, 4-5 october

  45. backup GDR Neutrinos, 4-5 october

  46. Air index GDR Neutrinos, 4-5 october

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