Radiation doses and LET distributions of cosmic rays

Journal Article · Tue May 01 04:00:00 EDT 1984 · Radiat. Res.; (United States)

DOI:https://doi.org/10.2307/3576230· OSTI ID:6775613

Silberberg, R; Tsao, C H; Adams, Jr, J H; Letaw, J R

Among cosmic rays, the heavy nuclei (HZE particles) like iron provide the dominant contribution to the dose equivalent during exposures in space. The LET distributions and radiation doses of cosmic-ray components have been calculated--with and without the quality factors--for a set of shielding and tissue self-shielding penetration depths. The relative contributions of heavy ions among solar flare particles to the dose equivalent are also explored. Outside the magnetosphere, at solar minimum, the product of the unshielded dose and the quality factors of cosmic-ray protons and heavy nuclei with atomic number Zgreater than or equal to 6 are about 5 and 47 rem/year, respectively. With 4 g/cm/sup 2/ aluminum shielding and at a depth of 5 cm in a biological phantom of 30 cm diameter, the respective values of the dose equivalents are about 4 and 11 rem/year. The dose equivalent of neutrons in the shielded case mentioned above is similar to that of protons. The biological risks are tentatively assessed in terms of the BEIR 1980 report. Uncertainties is risks due to possible large RBE values at low doses of high-LET radiation and due to the microbeam nature of damage by heavy ions are pointed out. Certain experiments and studies by radiobiologists are suggested for reducing the uncertainties in the estimates of the risks.

• Research Organization: Naval Research Lab., Washington, DC
• OSTI ID: 6775613
• Journal Information: Radiat. Res.; (United States), Journal Name: Radiat. Res.; (United States) Vol. 98:2; ISSN RAREA
• Country of Publication: United States
• Language: English

Related Subjects

61 RADIATION PROTECTION AND DOSIMETRY
655003* -- Medical Physics-- Dosimetry
CHARGED PARTICLES
COSMIC RADIATION
DATA
DOSE EQUIVALENTS
DOSES
ENERGY TRANSFER
EXPERIMENTAL DATA
HEAVY IONS
INFORMATION
IONIZING RADIATIONS
IONS
LET
MOCKUP
NUMERICAL DATA
PHANTOMS
RADIATION DOSES
RADIATIONS
SELF-SHIELDING
SHIELDING
SOLAR ACTIVITY
SOLAR FLARES
SPACE FLIGHT
STRUCTURAL MODELS