1. FIWAF 10/2002Pierre COLIN 1 a measurement of the fluorescence light in UV emitted by various gas (air, pure N 2...) when high-energy charged particles pass through it. What ? Who ? LAPP (Annecy France) : P. Colin, J.P Mendiburu, D. Naumov, P. Nedelec and J.P. Peigneux. Other groups involved / interested: ISN (France), APC (France), LIP (Portugal), CERN. and who wants to join us ! Measurement At Cern of Fluorescence Light Yield CERN test beam ( PS and SPS line ) Where ?

2. FIWAF 10/2002Pierre COLIN 2 Pressure ( 0 to 1 atm ) Temperature Air composition (O 2, Ar…) Impurities (humidity, aerosol…) Energy of particles (1.4MeV to 100GeV) Nature of high-energy particle ( e -, ,p…) Presence of Cerenkov light The purpose: Measure air light yield as a function of: Simulate the UV light produced by an air shower in the atmosphere. Pressure and temperature profile of atmosphere

3. FIWAF 10/2002Pierre COLIN 3 CERN Test beam facilities: Particle beam of electron, pion or proton. Flux : 10,000 particle/spill. Control room DAQ UV laser CERN-SPS-X5 Test Beam line e -,   beam Experimental area LineEnergyFrequency PS5-15 GeV1spill / 2s SPS25-100 GeV1spill / 14s

4. FIWAF 10/2002Pierre COLIN 4 Setup : beam PMT 1m Pressurised tank mirrors PMT beam Quartz window PMT We control temperature,pressure and gas composition in the tank. Mirror system collects the light (geometric efficiency: 57% ). several PMT detect the light ( with or without filters ). First simulation: in dry air at atmospheric pressure: 10 4 particles 3570 photoelectrons detected.

5. FIWAF 10/2002Pierre COLIN 5 Schedule : From Now to end of the year Setting up : A device to measure fluorescence yield A simulation of this device Beginning of 2003First test with: Radio active source (1.4MeV reference point). 337nm UV LASER. Summer 2003Measurement at CERN under test beam. Summer 2004Last measurement with test beam. Contact us : colin@lapp.in2p3.frcolin@lapp.in2p3.fr And first result at the next workshop…