DOSIMETRIC EVALUATION OF THE ALPHA FLUX IN SOLAR PARTICLE BEAMS.
Rept. no. 30,
NAVAL SCHOOL OF AVIATION MEDICINE PENSACOLA FLA
Pagination or Media Count:
Depth distributions of absorbed doses and dose equivalents in tissue are computed for the alpha and proton components of a typical rigidity spectrum of a large flare assuming a flux ratio of one to one. Even for the lowest investigated shield thickness of 1.75 gsq cm the total alpha dose is smaller than the proton dose and becomes even smaller with depth. The fractional high linear energy transfer alpha dose, however, is substantially larger than the corresponding proton dose and intersects the latter at 12 gsq cm depth in tissue. In spite of this, the combined mean local relative biological effectiveness of the total dose is predominantly determined by the protons. The findings indicate that the alpha component of flare beams creates a significant additional exposure only for cases of very low shielding, such as an astronaut outside the vehicle protected merely by the space suit. Author