Comparison of space radiation doses inside the Matroshka-torso phantom installed outside the ISS with the doses in a cosmonaut body in Orlan-M spacesuit during EVA

In the framework of the Russian space experiment Matroshka-R, in years 2004-2005 a special study of the dose distribution in anthropomorphic phantom was carried out. In the study, the phantom was installed on the outer surface of the International Space Station (ISS) in a special container that simulates the spacesuit shielding (Matroshka-Torso experiment). The purpose of this work is to compare the space radiation doses inside the Matroshka-Torso phantom with the doses in a cosmonaut body in Orlan-M spacesuit during an extra-vehicular activity (EVA) in similar conditions. For the calculation of the corresponding shielding functions, a geometrical model and technical description of the Matroshka-Torso phantom and container are used as well as technical description of the Orlan-M spacesuit and the results of its shielding study in an on ground gamma-transmission experiment. Dose calculations are made by using depth-dose curves for galactic cosmic rays, and trapped protons and electrons, the latter are taken from АЕ-8/АР-8 model. The calculated ratios of dose equivalents in critical organs of the Orlan-M spacesuit to those in Matroshka-Torso H(Orlan-M)/H(Matroshka-Torso) vary from 0.1 to 1.8 as dependent on the selected critical organ and solar cycle phase. The results obtained should be taken into account when transferring the data of the Matroshka-Torso experiment to the real EVA radiation conditions in Orlan-M spacesuit.