AIR WATCH: air-induced fluorescence by radiation laboratory experiments

We report preliminary measurements of the air UV fluorescence light yield as a function of pressure using as a stimulus hard x-rays. For comparison measurements in pure nitrogen are also reported. Knowledge of the air UV fluorescence light yield induced by hard x-rays is needed in order to evaluate the capability to detect, in an AIRWATCH FROM SPACE experiment, Gamma Ray Burst (GRB) events. The experiment was carried out a the LAX x-ray facility in Palermo, by using an high flux collimated x-ray photon beam. The experimental result indicate that the fluorescence yield is inversely proportional to the filling pressure. At pressures below 30 mbar, corresponding to the value for the upper atmospheric layers in which the X and gamma ray photons of the GRBs are absorbed, about 0.1 percent of the total energy of a GRB is transformed in UV photons. This makes possible the observation of the GRBs with the technique proposed in the AIRWATCH FROM SPACE experiment.© (1998) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.