Measurement of neutron dose and energy spectrum inside the tissue-equivalent spherical phantom and on its surface on the Russian segment of the International Space Station using bubble detectors during Matryoshka-R experiment

Results of neutron dose equivalent and energy spectrum measurements inside the channels of a spherical phantom located in «Rassvet» (MRM1) module of the Russian Segment of the International Space Station (ISS) are presented. The measurements were carried out with «Bubble dosimeter» scientific equipment in the framework of «Matryoshka-R» space experiment from May to August 2013 (ISS-35/36 expeditions). Neutron energy spectrum inside «Rassvet» module is in good agreement with measurements in other ISS modules and measurements onboard «Mir» orbital station and it has similar features («evaporation» and «cascade» peaks in 0,6...2,0 MeV and 15...50 MeV energy regions). On the spherical phantom surface, neutron daily dose equivalent rate is 154±13 μSv/day, while inside the spherical phantom it is 98±13 μSv/day, and contribution to the total neutron dose from > 15 MeV neutrons increased significantly.