Radiation Dose Study Of Astronauts Key Organs In Space Station

The requirement of safe measures and standard of manned space flight are very serious invarious space activities, which also needs advanced technical supports and owns the most complextechnical system. Space station is a long-term and more advanced manned space activity.Development of the manned space activities rapidly makes flighting in the space, space station settingup and residing, travelling time from dozens of hours to months in space station come true.Firstly, the radiation field characteristics are analyzed in space station orbit. Magnetic radiationbelts and cosmic ray models are summarized. Based on the radiation field models, we obtained thespectrum distribution of capture electrons, protons and GCR heavy ions. Radioactive particles interactwith materials were summarized. we adopt Al as space station shielding material, As the electron,proton and heavy ions interact with Al shielding layers of different thickness, selecting2g/cm2,5g/cm2,10g/cm2quality thickness，we use the Mulassis software to calculate and analyze spectrumdistribution of secondary particles.Secondly, this paper introduced the classification of digital human models, such as stylizedphantom, voxel phantom and boundary representation model, different kinds of foreign and Chinahuman phantoms were discussed. According to China’s adult male reference datas, the astronauts’mathematic model for key organs (blood-forming organs, skin, gonad and central nervous system)were established.Thirdly, using the Monte Carlo Geant4toolkit, space radiation particles energy spectrums asinputs, such as trapped electrons、SPEs in1972、heavy ions of solar-min and solar-max, we calculatedenergy deposit、absorbed dose、equivalent dose in the key organs. Research has shown that for trappedelectrons and SPEs, male gonad absorbed dose and equivalent dose are bigger; for high energy GCRs,absorbed dose and equivalent dose of the spinal cord and brain are bigger，and GCR proton, GCRhelium ion equivalent dose contribution to critical organs account for a major role. Due to highradiation weighting factor of GCR heavy ions, their contributions to critical organs equivalent doseand accumulative effects should not be ignored.