Long-Period Variations of the Neutron Component of the Radiation Background in the Area of the International Space Station according to the Data of the BTN-Neutron Space Experiment

This paper presents the results of the analysis of data from the BTN-Neutron space experiment carried out onboard the Russian module Zvezda, which is part of the International Space Station . The long observation period from 2008 to 2019 covers the end of the 23rd and almost all of the 24th solar cycle. This made it possible to estimate the amplitude of long-period variations of the neutron background outside the ISS due to solar modulation of galactic cosmic rays. For equatorial regions with a high geomagnetic-cutoff index, it does not exceed 10%, while the neutron background changes by almost 1.5–2 times in high-latitude regions around the Earth’s magnetic poles and the South Atlantic Magnetic Anomaly. For the periods of minimum and maximum solar activity within the 24th solar cycle, according to the BTN-Neutron experiment, maps of the distribution of the neutron-component power were constructed and the average neutron-dose rates that the cosmonauts could receive during these periods were estimated. It was shown that, for maximum and minimum solar activity, the average neutron dose rate varies from 25 to 35 µSv/day for neutrons with energies below 15 MeV.