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Fluorescence Light Yield SpectrumBetween 300 et 400 nmThe Space WindowIncertainties on FLY measurements: 30%Davidson et ONeil (1964)Bunner (1967)

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What to measure?Air & N2 FLY as a function of:Reproduce & study in laboratory the light induced by an atmospheric shower Pression (0 to 1 atm ) Temperature (-50 20 oC) Air composition (O2, Ar) Impurities (humidity, aerosol) Particule energy Particule density Particule nature (e-,,, m, p) Shower age (#X0) Cherenkov contribution LifetimesN2 for ref.comparison

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History - ReferencesA.N. Bunner, PhD thesis, Cornell, 1967:Cosmic Rays detection by Atmospheric . FluorescenceNitrogen fluorescence spectrum between 300 and 400nmCompilation Error ~ 30 % on yield at each lH. Brunet, PhD thesis, Toulouse,1973:Destruction des tats C3Pu de N2 dans lazote pur et mlange avec O2, H2O, CO2,CH4Rediscovered at Bad Liebenzell (second workshop)Kakimoto et al. (1995):measurement of total yield between 300 and 400 nmthree lines (337 nm, 357 nm, 391 nm)Error > 10 %

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A New Field emergedGoal: understand the fluorescence yield to better than 10 %

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* : published paper(s)Experimental approach: Spectroscopy: Dl ~ 1 nm Narrow band filters: Dl ~ 10 nm Large band filters: Dl ~ 100 nm

NameParticle sourceNumber of particlesParticle energyNagano*90Sr 0.85 MeVAirlight90Sr 2.3 MeVMACFLY90Sr , e-, e+,, m (CERN)10,000 per spill2.3 MeV5-100 GeVCoimbra241Am (a), 90Sr 2.8 MeVAIRFLYe-, e+ (DAfNE)1-101025-800 MeVFLASHe- (SLAC)107-109

Experimental set-up July 2004PM1, PM2 - XP2020QPM3 R1166Cooling unitPressure sensorto vacuum pumpPM3scintillator

Raw data (a particle excitation)P0=818 hPar = 0,80 roP0=688 hPar = 0,68 roP0=434 hPar = 0,43 roP0 = 520 hPar = 0,51 roP0 = 600 hPar = 0,59 ro

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OutlookDelicate measurements Goal 10% syst.All the projects are Running ExperimentsLines + Filters measurements performedPressure dependence (all)Temperature (Coimbra, AirFly)First Shower age FLY measurementsMacFly, FLASHSimulation G4Needed, matureAbsolute calibrationCerenkov, Rayleigh,Difficult, neededTheory/Modelsimproving

Where the FLY story ends?

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