Staying Below Radiation Exposure Limits: Maximum Levels of Solar Energetic Proton Event Fluence
- Paper number
IAC-17,A1,5,13,x36589
- Author
Prof.Dr. Lawrence Townsend, University of Tennessee, United States
- Coauthor
Mr. Wouter de Wet, University of Tennessee, United States
- Coauthor
Mr. Fahad Zaman, University of Tennessee, United States
- Year
2017
- Abstract
Current radiation limits for NASA astronauts are provided to mitigate risks of developing a fatal cancer and to limit short term and non-cancer effects, preventing clinically significant degradation of crew performance, sickness or death. In order to limit the risk of developing a fatal cancer, effective doses, which are age and gender dependent, are limited to a 3% risk of exposure induced death (REID) at the 95% confidence level. They are determined for the specific mission and radiation environment (galactic cosmic ray, solar particle event, trapped radiation belts, etc.). Short term and non-cancer limits are applied to the skin, eye lens, blood forming organs, cardiovascular, and central nervous systems. NASA policy also dictates that radiation exposures follow the ALARA (As Low As Reasonably Achievable) principle. Radiation exposures to crew members depend upon the incident proton fluence levels, their energy distributions, and the effectiveness of any protective shielding. In this work, we report estimates of maximum proton fluence levels for different energy spectra that would keep organ doses and effective doses for male and female crewmembers below applicable limits for a range of nominal shielding thicknesses. In each case we indicate which organ dose is most limiting, and also indicate if the effective dose received by the crew member is more limiting than any organ dose.
- Abstract document
- Manuscript document
IAC-17,A1,5,13,x36589.pdf (🔒 authorized access only).
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