国际学术会议海报模板27-academic conference poste.ppt

The SIEVERT system: taking into account
GCR and SPE effects aboard aircraft
N. Fuller a, P. Lantos a and . Bottollier-Depois b
Recently, the European Commission (EU directive 96/29/EURATOM) included the exposure of aircraft crew to cosmic radiation as occupational exposure. It was following the recommendations of the International Commission on Radiological Protection (ICRP, 1991) concerning the exposure to enhanced or elevated levels of radiation from natural sources. The effective dose should not be higher than 100 mSv over 5 years with a maximum of 50 mSv for a given year (specific rules apply to pregnant air crew).
The radiation doses onboard aircraft are due to two sources: Galactic Cosmic Rays (GCR) and Solar Proton Events (SPE). The doses are the result of the numerous secondary particles created in the atmosphere by high energy primary particles. The galactic component is permanent but modulated by the solar activity in the course of the 11-year solar cycle. The modulation parameter is an input of models such as EPCARD (Schraube, 1999) which computes the dose for GCR at any point in space up to an altitude of 80,000 feet. The SPE, when detected at ground level by neutron monitors (GLE), may enhance significantly the doses received onboard aircraft. A specific semi-empirical model named SiGLE was developed (Lantos & Fuller, 2003) to take into account these events.