Documents in the NTIS Technical Reports collection are the results of federally funded research. They are directly submitted to or collected by NTIS from Federal agencies for permanent accessibility to industry, academia and the public.  Before purchasing from NTIS, you may want to check for free access from (1) the issuing organization's website; (2) the U.S. Government Printing Office's Federal Digital System website http://www.gpo.gov/fdsys; (3) the federal government Internet portal USA.gov; or (4) a web search conducted using a commercial search engine such as http://www.google.com.
Accession Number N20130010711
Title Correlated Uncertainties in Radiation Shielding Effectiveness.
Publication Date Feb 2013
Media Count 70p
Personal Author C. M. Werneth K. M. Maung L. W. Townsend M. S. Clowdsley S. R. Blattnig
Abstract The space radiation environment is composed of energetic particles which can deliver harmful doses of radiation that may lead to acute radiation sickness, cancer, and even death for insufficiently shielded crew members. Spacecraft shielding must provide structural integrity and minimize the risk associated with radiation exposure. The risk of radiation exposure induced death (REID) is a measure of the risk of dying from cancer induced by radiation exposure. Uncertainties in the risk projection model, quality factor, and spectral fluence are folded into the calculation of the REID by sampling from probability distribution functions. Consequently, determining optimal shielding materials that reduce the REID in a statistically significant manner has been found to be difficult. In this work, the difference of the REID distributions for different materials is used to study the effect of composition on shielding effectiveness. It is shown that the use of correlated uncertainties allows for the determination of statistically significant differences between materials despite the large uncertainties in the quality factor. This is in contrast to previous methods where uncertainties have been generally treated as uncorrelated. It is concluded that the use of correlated quality factor uncertainties greatly reduces the uncertainty in the assessment of shielding effectiveness for the mitigation of radiation exposure.
Keywords Aerospace environments
Cancer
Energetic particles
Extraterrestrial radiation
Probability distribution functions
Radiation dosage
Radiation shielding
Risk
Spacecraft shielding
Structural failure

 
Source Agency National Aeronautics and Space Administration
NTIS Subject Category 54C - Astrophysics
57V - Radiobiology
Corporate Author National Aeronautics and Space Administration, Hampton, VA. Langley Research Center.
Document Type Technical report
Title Note N/A
NTIS Issue Number 1320
Contract Number N/A

Science and Technology Highlights

See a sampling of the latest scientific, technical and engineering information from NTIS in the NTIS Technical Reports Newsletter

Acrobat Reader Mobile    Acrobat Reader