The results of cosmic radiation in-flight TEPC measurements during the CAATER flight campaign and comparison with simulation.

The European-Commission-supported project DOSMAX (Dosimetry of Aircrew Exposure to Radiation During Solar Maximum) was aimed at measuring aircrew exposure to cosmic radiation on-board the aircraft during solar maximum. During a dedicated international comparison mission (Co-ordinated Access to Aircraft for Transnational Environmental Research; CAATER) different measurement techniques have been compared by six European institutes (Results of the CAATER Mission, DOSMAX Meeting, Dublin, June 2004). In this paper, we present the tissue-equivalent proportional counter (TEPC) measurements carried out by ARC Seibersdorf research (ARCS), Austria, and Institut de Radioprotection et de Sûreté Nucléaire (IRSN), France, together with a comparison with simulation results under the same conditions. The whole flight campaign consists of four different in-flight investigations performed at two different geographical positions at 12.2 km (FL 400) and 9.8 km (FL 320). One location was chosen above Rome (42 degrees North, 12 degrees East), Italy, for high cut-off rigidity (6.4 GV) and the second above Aalborg (57 degrees North, 10 degrees East), Denmark, for low cut-off rigidity (1.8 GV). The TEPC measurements are presented in terms of absorbed dose and ambient dose equivalent as well as microdosimetric spectra as a function of lineal energy. For the same conditions of the CAATER flights the response of the TEPC has also been simulated by using the Monte Carlo Transport Code FLUKA (version 2003). The results from simulations are compared with measurements and they show a reasonable agreement.