Accession Number : AD0648299

Title :   LINEAR ENERGY TRANSFER SPECTRA AND DOSE EQUIVALENTS OF GALACTIC RADIATION EXPOSURE IN SPACE,

Corporate Author : NAVAL AEROSPACE MEDICAL INST PENSACOLA FLA

Personal Author(s) : Schaefer,Hermann J.

Report Date : 09 DEC 1966

Pagination or Media Count : 22

Abstract : In assessing the astronaut's exposure from galactic cosmic rays on space missions of long duration conversion of absorbed doses to dose equivalents is required. Since a large part of the dose contribution from heavy primaries is produced at Linear Energy Transfer (LET) values beyond the range for which radiobiological data are available, it seems preferable to analyze the LET distributions themselves and to compare them to standard x-rays rather than to assume arbitrary values for the Relative Biological Effectiveness(RBE). The local LET distributions in tissue are found to be extremely skewed, with a large maximum at the relativistic minimum LET. Lined up on the LET scale, they cover the very wide interval from 0.18 to 2790 kev/micron T as compared to an interval from 0.4 to 35 kev/micron T for standard x-rays. Applying the RBE formula of the RBE Committee of the ICRP and a saturation value of 10 leads to a grand mean RBE of 1.82 for the total absorbed dose of 13 millirads/24 hours from primaries. (Author)

Descriptors :   (*COSMIC RAYS, HEALTH PHYSICS), (*ASTRONAUTS, *RADIATION HAZARDS), SPACE ENVIRONMENTS, RADIATION EFFECTS, DOSE RATE, SOLAR RADIATION, NUCLEAR RADIATION SPECTROSCOPY, CHARGED PARTICLES, NUCLEONS

Subject Categories : Radiobiology

Distribution Statement : APPROVED FOR PUBLIC RELEASE