AIRFLY: Air Fluorescence Induced by Electrons in a Wide Energy Range

The goal of the AIRFLY (AIR FLuorescence Yield) experiment is to measure the fluorescence yield in atmospheric gases with better than 10% precision. AIRFLY takes data in 2003 at the Beam Test Facility of the INFN Laboratori Nazionali di Frascati, which will allow a measurement of the fluorescence yield induced by electrons in a wide range around their critical energy. Details of the experimental apparatus and first tests performed on the beam line are reported.