Altitude dependence of fluorescence light emission by extensive air showers

Understand

Fluorescence light is induced by extensive air showers while developing in the Earth's atmosphere.

• The number of emitted fluorescence photons depends on the conditions of the air and on the energy deposited by the shower particles at every stage of the development.
• In a previous model calculation, the pressure and temperature dependences of the fluorescence yield have been studied on the basis of kinetic gas theory, assuming temperature-independent molecular collision cross-sections.
• In this work we investigate the importance of temperature-dependent collision cross-sections and of water vapour quenching on the expected fluorescence yield.