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Nitrogen fluorescence in air for observing extensive air showers

Nitrogen fluorescence in air for observing extensive air showers. B . Keilhauer. 8th Air Fluorescence Workshop Karlsruhe, 12 – 14 September 2011. Delegation of the workshop: M. Bohacova M. Fraga B. Keilhauer J. Matthews N. Sakaki Y. Tameda Y. Tsunesada A. Ulrich.

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Nitrogen fluorescence in air for observing extensive air showers

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  1. Nitrogen fluorescence in air for observing extensive air showers B. Keilhauer 8th Air Fluorescence WorkshopKarlsruhe, 12 – 14 September 2011 Delegation of the workshop: M. BohacovaM. FragaB. KeilhauerJ. MatthewsN. SakakiY. TamedaY. TsunesadaA. Ulrich http://www.kceta.kit.edu/8afw2011/

  2. Interpretation of Cosmic Rays Eur. Phys. J. Plus (2012) 127: 87 V. Berezinsky, UHECR2012 B. Keilhauer AtmoHEAD 2013

  3. Interpretation of Cosmic Rays- scaling of the absolute energy - direct data of the experiments re-scaled data J(E)E3 , eV2 m-2 s-1 sr-1 E , eV E , eV Prog. Part. Nucl. Phys. 63(2009) 293 B. Keilhauer AtmoHEAD 2013

  4. Interpretation of Cosmic Rays- determination of the composition - M. Unger, UHECR2012 Astroparticle Physics 39–40 (2012) 33–43 B. Keilhauer AtmoHEAD 2013

  5. Detection Principles Transmission B. Keilhauer AtmoHEAD 2013 Emission of isotropic Fluorescence- and forward-beamed Cherenkov-light Air shower Transmission Shower axis

  6. A.N. Bunner, PhD thesis, Cornell, 1967 Fluorescence Light Production • excitation of nitrogen in air because of energy deposit from EAS • direct excitation of 1N via ionization • collisions with low energy electrons with spin change for 2P • down cascading from higher level of 2P • spontaneous de-excitation → fluorescence light B. Keilhauer AtmoHEAD 2013

  7. Fluorescence Light Production • excitation of nitrogen in air because of energy deposit from EAS • spontaneous de-excitation → fluorescence light • atmosphere dependence because of quenching 800 hPa, 293 K NIM A597(2008)41 B. Keilhauer AtmoHEAD 2013

  8. Formulas for a Fluorescence Description B. Keilhauer AtmoHEAD 2013

  9. Formulas for a Fluorescence Description a) absolute yield value of a reference transmission: fluorescence yield in photons emitted per MeV of energy deposited at given experimental conditions p0 and T0 B. Keilhauer AtmoHEAD 2013

  10. Formulas for a Fluorescence Description a) absolute yield value of a reference transmission b) wavelengths-dependent spectrum: ratio of individual transitions of the spectrum between about 280 and 430 nm to the strength of the transitions at 337.1 nm B. Keilhauer AtmoHEAD 2013

  11. Formulas for a Fluorescence Description a) absolute yield value of a reference transmission b) wavelengths-dependent spectrum c) pressure dependence in dry air: characteristic pressure of dry air at experimental conditions T0 B. Keilhauer AtmoHEAD 2013

  12. Formulas for a Fluorescence Description a) absolute yield value of a reference transmission b) wavelengths-dependent spectrum c) pressure dependence in dry air d) humidity quenching: p′H2O(λ, T0) - characteristic pressure of water vapor at experimental conditions T0 B. Keilhauer AtmoHEAD 2013

  13. Formulas for a Fluorescence Description a) absolute yield value of a reference transmission b) wavelengths-dependent spectrum c) pressure dependence in dry air d) humidity quenching e) temperature-dependent collisional cross sections: αλ- exponent of the power law describing the T-dependent collisional cross sections for each λ B. Keilhauer AtmoHEAD 2013

  14. Formulas for a Fluorescence Description a) absolute yield value of a reference transmission b) wavelengths-dependent spectrum c) pressure dependence in dry air d) humidity quenching e) temperature-dependent collisional cross sections • Non-radiative de-excitation of excited nitrogen molecules • only 1 value for each band system B. Keilhauer AtmoHEAD 2013

  15. Strategy • Describing the spectrum and the dependences on atmospheric conditions: • common altitude-dependent shape • requires adequate knowledge of atmospheric profiles • Finding the absolute scaling: • direct shift of reconstructed primary E of air showers b) wavelengths-dependent spectrum c) pressure dependence in dry air d) humidity quenching e) temperature-dependent collisional cross sections B. Keilhauer AtmoHEAD 2013

  16. Suggested Reference Fluorescence Description - spectral intensities - spectral intensities Iλ as measured by AIRFLY; 34 transitions between 296 and 428 nm The sum of the yield differs by -1.66% (Ulrich et al.), +2.08% (Nagano et al.),-1.70% (FLASH). B. Keilhauer et al. , proc. UHECR 2012 B. Keilhauer AtmoHEAD 2013

  17. Suggested Reference Fluorescence Description - pressure dependence- • p‘air: • one value for each band system; • weighted averages for 2P(0,x), (1,x), (2,x), (3,x), 1N (0,x), (1,x), GH (0,x) derived from AIRFLY measurements; • for weak transitions, as 2P(4,x), further GH, estimates from their publicatation B. Keilhauer AtmoHEAD 2013

  18. Suggested Reference Fluorescence Description - humidity dependence- • p‘H2O: • one value for each band system; • weighted averages for 2P (0,x), (1,x), (2,x), 1N (0,x) derived from Sakaki et al. measurements using the photon yield and the lifetime technique • for weak transitions of 2P(3,x) and 2P(4,x) use weighted average of p‘H2O of 2P (1,x) and (2,x) bands (4.8% of the total emission at p0, T0) • for all others set to Zero (2.1% of the total emission at p0, T0) B. Keilhauer AtmoHEAD 2013

  19. Systematic study from Sakaki et al. - humidity dependence- N. Sakaki, 8AFW 2011 B. Keilhauer AtmoHEAD 2013

  20. Suggested Reference Fluorescence Description - temp.-dep. collisional cross sections - • α-coefficient: • one value for each band system; • weighted average for 2P(0,x) and 1N(0,x) derived from AIRFLY measurements • for weak transitions of 2P(3,x) and 2P(4,x) use weighted average of p‘H2O of 2P (1,x) and (2,x) bands (4.8% of the total emission at p0, T0) • for all others set to Zero (2.1% of the total emission at p0, T0) B. Keilhauer AtmoHEAD 2013

  21. Parameter Set for the Reference Fluorescence Description B. Keilhauer et al. , proc. UHECR 2012 B. Keilhauer AtmoHEAD 2013

  22. „academic“ fluorescence yield - scaling according Nagano et al. (2004) - Y. Tsunesada et al. , proc. ICRC 2013

  23. „academic“ fluorescence yield- variations of p‘H2O - B. Keilhauer et al. , proc. UHECR 2012 B. Keilhauer AtmoHEAD 2013

  24. „academic“ fluorescence yield- variations of - B. Keilhauer et al. , proc. UHECR 2012 B. Keilhauer AtmoHEAD 2013

  25. Application to air shower reconstruction- same absolute scaling, Auger reconstruction framework - Mean: -9.98 % 0.34 % Mean: 0.71 g cm-2 1.63 g cm-2 RMS: 1.76 % 1.22 % RMS: 1.25 g cm-2 3.56 g cm-2 B. Keilhauer et al. , proc. UHECR 2012 B. Keilhauer AtmoHEAD 2013

  26. Systematics in air shower reconstruction- same absolute scaling, Auger reconstruction framework - B. Keilhauer et al. , proc. UHECR 2012 B. Keilhauer AtmoHEAD 2013

  27. Systematics in air shower reconstruction- same absolute scaling, Auger reconstruction framework - B. Keilhauer et al. , proc. UHECR 2012 B. Keilhauer AtmoHEAD 2013

  28. Systematics in air shower reconstruction- same absolute scaling, Auger reconstruction framework - B. Keilhauer et al. , proc. UHECR 2012 B. Keilhauer AtmoHEAD 2013

  29. Application to air shower reconstruction- different absolute scaling - both „Nagano“-scaling TA „Kakimoto“-scaling Mean: 0.3 % Mean: -6.6 g cm-2 Mean: 8.6 % Mean: 0.7 g cm-2 B. Keilhauer AtmoHEAD 2013

  30. Influence of atmospheric profiles monthly models GDAS Astropart. Phys. 35 (2012) 591 B. Keilhauer AtmoHEAD 2013

  31. Conclusion • a reference fluorescence description has been developed • all known atmospheric effects are implemented • application to air shower reconstructions are done for Auger and TA, but not used in the official experiments‘ reconstructions yet • first details are published in the proc. of UHECR2012 • more in the proc. of ICRC 2013

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