Astronaut Radiation Dose Calculation With A New Galactic Cosmic Ray Model And The AMS-02 Data

In recent years,the success of China’s Shenzhou series of manned spacecraft and the series of the Tiangong space station missions shows that China has the foundation to carry out farther interplanetary manned space activities,which is of great significance to China and the world.But due to the lack of protection from the Earth’s magnetic field,astronauts are exposed to cosmic rays.Therefore,before carrying out a manned space mission,it is necessary to determine the radiation dose from galactic cosmic rays received by astronauts to ensure the life safety in the space radiation environment during the manned space mission.In order to study the radiation absorbed dose,dose equivalent and effective dose equivalent received by astronauts and their sensitive organs,this paper simulates the radiation environment conditions at 1AU,and evaluates and calculates the radiation dose received by astronauts.In this paper,the AMS-02 data are used to calculate the GCR spectrum at 1AU based on the Parker transport equation and the time-varying solar modulation model,so as to improve the calculation accuracy of the radiation dose to astronauts from high-energy cosmic rays outside the solar system.The model reproduced observations from PAMELA and AMS-02 from July 2006 to October 2019.The radiation dose calculated from the modulation model and the AMS-02 spectrum in the same rigidity range,the dose caused by proton and helium is better than 1% in terms of time dependence,and the dose agreement of the six most contributing galactic cosmic ray elements is in average of 2% over 7 or 8.5 years.Therefore,the error of the modulation model in reproducing the AMS-02 energy spectrum has been reduced to a level of?2% worldwide,which has become a secondary source of error in the determination of astronaut doses.Using galactic cosmic ray energy spectrum as input,based on the human voxel model constructed in the International Commission on Radiological Protection(ICRP110),using ICRP60 and NASA-defined relative biological effect factors,this work counts the radiation dose for all human tissues or organs that are sensitive to radiation dose and need to consider deterministic effects,respectively.I have also calculated parameters such as absorbed dose,dose equivalent,and effective dose equivalence in sensitive organs in astronauts’ bodies,and analyzed the results.A 13-year time-dependent dose rate analysis showed that astronauts received an effective dose equivalent of 55-58 c Sv/yr during the solar maximum(January 2010)and 26 c Sv/yr during the solar maximum(February 2014),with the effective dose equivalent in the solar minimum being approximately twice that of the solar maximum.Due to the selfshielding effect,the skin dose equivalent is higher than that of the other 14 groups,which is nearly 40% to 25% higher than the effective dose equivalent during the solar minimum and solar maximum,respectively.The six elements that contribute the most radiation dose are always protons,helium,oxygen,magnesium,silicon and iron,which together account for more than 74% of the total contribution,and the other individual elements always contribute less than5%.Because gender does not differ much in the calculation of radiation doses,this article averages the sexes when calculating radiation doses,and then shows two quality factors.Although the choice of quality factor does not affect the physical process,the dose equivalent calculated by the NASA-defined quality factor is usually slightly larger than the quality factor defined by ICRP60.