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Motohiko Nagano Fukui University of Technology

22 July 2004, Leeds. New measurement on photon yields from air and the application to the energy estimation of primary cosmic rays. Motohiko Nagano Fukui University of Technology. Collaboration with K.Kobayakawa, N.Sakaki and K.Ando. European Symposium at Leeds in 1970.

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Motohiko Nagano Fukui University of Technology

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  1. 22 July 2004, Leeds New measurement on photon yields from air and the application to the energy estimationof primary cosmic rays Motohiko Nagano Fukui University of Technology Collaboration with K.Kobayakawa, N.Sakaki and K.Ando

  2. European Symposium at Leeds in 1970 3rd International Workshop on Ultrahigh-energy Cosmic Rays (2004) in honor of Alan Watson Haverah Park in 1970 Raidio observation Central station Recording system Symposium Water tank

  3. Workshops on Air Fluorescence FIWAF 02 at Salt Lake City, October 2002 at Bad Liebenzell, Dec. 2003 Details are in http://www.auger.de/events/air-light-03

  4. Summary of Experiments by Bianca Keilhauer Arqueros, Madrid, < 30 keV Nagano, Fukui Univ. Waldenmaier, AirLight Gorodetzky, Paris Colin, MacFly 1. phase Fraga, LIP-Lisboa Kemp, Campinas 1. phase Privitera, AIRFLY, e±-beam at BTF, 50-750 MeV Colin, MacFly 2. ph., e±/μ-beam at CERN 25-100 GeV Reil, Flash, e--beam at SLAC 28 GeV Kemp, 2. ph., e--beam at LNLS1.37 GeV Ulrich, Munich, 12 keV 2. phase: medical acc. 5-12 MeV www-ta.icrr.u-tokyo.ac.jp/ws-feb04

  5. InM.Nagano, K.Kobayakawa, N.Sakaki and K.Ando ;Astroparticle Physics, 20 (2003) 293-309 • Fluorescence yields were measured with 6 narrow band filters. • Yields in unmeasured bands were estimated by multiply the yields given in Bunner, taking into account the average ratio of our measured values to the corresponding values listed in Bunner.

  6. Filter 15 filters are used. 391.9nm 337.7nm

  7. 90Sr （28.8y） β 90Y （64.1h） β 2.28MeV 3.3MBq 90Zr Electron beam A photon counting and thin target technique is used. average 0.85MeV 0.02% 99.98% 1.75MeV

  8. Systematic errors Statistical error in each run is less than 3%.

  9. : Energy loss (g cm-2) : Fluorescence efficiency in the absence of collisional quenching (Fluorescence efficiency is defined by the radiated energy divided by the energy loss of the electron in a unit length) : fraction of available energy kept after collisional losses p’ is the reference pressure Equation of state of a gas, p=ρRT, where R is specific gas constant. Photon yields per m : Density : Photon energy fromBunner

  10. Nitrogen Red curves are Yi after subtraction of other bands in the filter.

  11. Air Mixtures of N2 : 78.8 % O2 : 21.2 %

  12. Photon yields between 300 and 406nm at 1 atmospheric pressure 12 keV Average of three experiments

  13. Present (0.85 MeV) Davidson and O’Neil(50 keV) Mitchell(8 keV) Kakimoto et al.(1.4 MeV) Comparison of fluorescence efficiencies

  14. Measurements between 300 and 1000MeVKakimoto et al. NIMA372(1995)244. Electrons from the electron synchrotron of the INS, University of Tokyo.

  15. Energy dependence of photon yields Air of 1 atm. pressure O : Kakimoto et al. cited from Ueno dE/dx curves are adjusted at 1.2 MeV

  16. P. Privitera Energy dependence of fluorescence yield AirLight03, Bad Liebenzell, Dec. 2003 • UG6 filter • The scan was performed several times with consistent results. • Preliminary • Np.e.(fluor.) • ADCcal x E/442 AIRFLY • Limited by multiple scattering on 1.5 mm thick exit Al window. The scan went down to 50 MeV. • Positrons (493 MeV) gave same yield within 3%

  17. Photon yields as a function of density and temperature reference pressure at 20oC

  18. CIRA1986 and US standard atmosphere V.Rizi, Airlight03 at Bad Liebenzell, 2003 COSPAR International Reference Atmosphere

  19. Altitude dependence of photon yieldsper meter per electron of 0.85 MeV US Standard Atmosphere 1966 US Standard Atmosphere 1976

  20. Photon yields in damp air Vapour pressure 9.5 hPa 13.4 hPa Nagano et al. UHECR Conference at Annecy, 2001

  21. Photon yields between 300 and 406nm

  22. Photon attenuation with distance Raileigh scattering only important at far distance

  23. Energy Estimation C. Song et al., Astroparticle Phys. 14(2000)7 Electromagnetic shower: mean Ionization loss rate: CR calorimetric energy: Missing Energy: (m,n,…)

  24. Application of the photon yields to the energy estimation of UHECR B.Dawson, GAP-2002-067(2002) fraction of the flux L(x) in bin i at depth x M.Risse and D.Hech, Astroparticle Physics 20(2004) 661

  25. By N. Sakaki Assumptions: • CORSIKA 6.020 with QGSJET（M.Risse and D.Heck, Astropart. Phys. 20 (2004) 661 • proton, E=1019eV and 1020eV, θ=0o, 60o • Emitted photons from dE/dx(g/cm2) • The observation height is 0 m a.s.l. • Transmission by Rayleigh scattering (XR=2974 g/cm2) • Transmission by Mie scattering (scale height HM=1.2 km, horizontal attenuation length LM=25 km) • US standard atmosphere 1976 • Wave length dependence of HiRes filter transmission and quantum efficiency of Hires PMT are included

  26. Comparison of observed total photon number in various conditions by N.Sakaki

  27. Energy spectrum of world data

  28. Conclusions • From the pressure dependences of photon yields, fluorescence efficiencies for 15 bands in the absence of collisional quenching are determined. • Photon yields are determined as a function of the gas density and the temperature for 15 bands. • Total photon yields between 300nm - 406 nm are 26% larger than the summary by Bunner at 1013 hPa and at 20oC. • Those are 18% larger than those used by the HiRes group. • In estimating the primary energy of cosmic rays, it would be more realistic to estimate the energy deposit for each angular bin from the observed photons using the pressure dependence of fluorescence efficiencies of each band, whose values are determined and available now. M.Nagano et al. astroph-0406474

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