INVESTIGATION OF THE INFLUENCE OF THE POSITION INSIDE A SMALL AIRCRAFT ON THE COSMIC-RADIATION-INDUCED DOSE.

This article report the measurements on-board a small aircraft at the same altitude and around the same geographic coordinates. The measurements of Ambient Dose Equivalent Rate (H*(10)) were performed in several positions inside the aircraft, close and far from the pilot location and the discrimination between neutron and non-neutron components. The results show that the neutrons are attenuated close to fuel depots and the non-neutron component appears to have the opposite behavior inside the aircraft. These experimental results are also confronted with results from Monte Carlo simulation, obtained with the MCNPX code, using a simplified model of the Learjet-type aircraft and a modeling of the standard atmosphere, which reproduces the real energy and angular distribution of the particles. The Monte Carlo simulation agreed with the experimental measurements and shows that the total H*(10) presents small variation (around 1%) between the positions inside aircraft, although the neutron spectra present significant variations.