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Galactic cosmic rays and cell-hit frequencies outside the magnetosphere
1Lawrence Berkeley Laboratory, University of California 94720.
Advances in Space Research : the Official Journal of the Committee on Space Research (COSPAR)
|January 1, 1989
Summary
Space travelers face significant galactic cosmic radiation (GCR) exposure. Shielding reduces radiation dose equivalent by 2.85 times, but high-charge particle cell hits remain a concern for long missions.
Area of Science:
- Space science
- Radiation biology
- Astrophysics
Background:
- Space travelers are exposed to galactic cosmic radiation (GCR) outside Earth's magnetosphere.
- Assessing GCR exposure is critical for astronaut health and mission planning.
Purpose of the Study:
- To evaluate space traveler exposure to GCR.
- To analyze particle fluences and shielding effectiveness for different configurations.
- To understand the impact of high-charge particles on cellular targets.
Main Methods:
- Calculated high-energy particle fluences (primary and secondary) traversing a 100-micron² area simulating a cell nucleus.
- Modeled two shielding configurations: a 1 g/cm² aluminum shell and a 4 g/cm² aluminum shell with a water phantom.
- Analyzed particle charge components and their frequencies within shielding.
Main Results:
- The more heavily shielded configuration reduced dose equivalent by a factor of 2.85 compared to free space.
- For a three-year mission, 33% of cells in the heavily shielded configuration would be hit by at least one high-charge particle (Z>10).
- Approximately half the dose reduction was from absorbed dose decrease, and half from quality factor decrease.
Conclusions:
- Shielding significantly reduces overall radiation dose but does not eliminate risks from high-charge particles.
- Further study is needed on single high-Z particle effects on cancer-risk and neural cells.
- Synergistic effects of high-charge particles with protons and helium ions warrant investigation.