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The SiGLE model, which assesses the radiation dose during major solar proton events, has evolved into a real time tool

SiGLE was developed in the late 1990s to meet the new European and French standards for the monitoring of radiation doses received by aircrew (see the publications page on the CERCLe website). This tool has been used in an operational way within the SIEVERT system to take into account the additional doses received by aircrew during intense solar energetic particle events. More recently, and particularly thanks to the development of the NMDB database, the evolution of SiGLE towards a real-time tool has become possible.

SiGLE_RT detects "GLEs" (Ground Level Events) in real time by analyzing the data from the neutron monitors. The SiGLE semi-empirical approach then makes the calculation of dose rates at different altitudes/latitudes/longitudes very fast. The anisotropy of the particles, as seen by the network of neutron monitors, is also taken into account in order to give the most precise information.

As long as the event is in progress, the dose rate maps are refreshed every 5 minutes. We show here the result of the simulation of a big event (January 20, 2005), at the moment of the maximum. When the event is over, a post analysis work begins. It consists in comparing the doses calculated with doses measured (or not!) by the network of dosimeters that fly continuously on about 35 Air France aircraft under the supervision of IRSN. These data, along with a detailed analysis of the energy spectrum of the solar particles, validates the model and also makes it possible to constantly improve it. Such an alert system with dose rate assessement could be used in the global space weather information service planned under the umbrella of the International Civil Aviation Organisation (ICAO) to provide very useful informations to pilots.

Karl-Ludwig Klein, LESIA Observatoire de Paris, PSL, CNRS, Meudon
Nicolas Fuller, LESIA Observatoire de Paris, PSL, CNRS, Meudon