Calculations of Cosmic-ray Helium Transport in Shielding Materials
Author: Francis A. Cucinotta
Publisher:
Published: 1993
Total Pages: 40
ISBN-13:
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Author: Francis A. Cucinotta
Publisher:
Published: 1993
Total Pages: 40
ISBN-13:
DOWNLOAD EBOOKAuthor: National Aeronautics and Space Adm Nasa
Publisher: Independently Published
Published: 2018-10-23
Total Pages: 38
ISBN-13: 9781729124345
DOWNLOAD EBOOKThe transport of galactic cosmic-ray helium nuclei and their secondaries through bulk shielding is considered using the straight-ahead approximation to the Boltzmann equation. A data base for nuclear interaction cross sections and secondary particle energy spectra for high-energy light-ion breakup is presented. The importance of the light ions H-2, H-3, and He-3 for cosmic-ray risk estimation is discussed, and the estimates of the fractional contribution to the neutron flux from helium interactions compared with other particle interactions are presented using a 1977 solar minimum cosmic-ray spectrum. Cucinotta, Francis A. Langley Research Center RTOP 199-45-16-11
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Publisher:
Published: 1995
Total Pages: 488
ISBN-13:
DOWNLOAD EBOOKLists citations with abstracts for aerospace related reports obtained from world wide sources and announces documents that have recently been entered into the NASA Scientific and Technical Information Database.
Author: National Aeronautics and Space Adm Nasa
Publisher: Independently Published
Published: 2018-12-31
Total Pages: 34
ISBN-13: 9781792697661
DOWNLOAD EBOOKEstimates of radiation risk from galactic cosmic rays are presented for manned interplanetary missions. The calculations use the Naval Research Laboratory cosmic ray spectrum model as input into the Langley Research Center galactic cosmic ray transport code. This transport code, which transports both heavy ions and nucleons, can be used with any number of layers of target material, consisting of up to five different arbitrary constituents per layer. Calculated galactic cosmic ray fluxes, dose and dose equivalents behind various thicknesses of aluminum, water and liquid hydrogen shielding are presented for the solar minimum period. Estimates of risk to the skin and the blood-forming organs (BFO) are made using 0-cm and 5-cm depth dose/dose equivalent values, respectively, for water. These results indicate that at least 3.5 g/sq cm (3.5 cm) of water, or 6.5 g/sq cm (2.4 cm) of aluminum, or 1.0 g/sq cm (14 cm) of liquid hydrogen shielding is required to reduce the annual exposure below the currently recommended BFO limit of 0.5 Sv. Because of large uncertainties in fragmentation parameters and the input cosmic ray spectrum, these exposure estimates may be uncertain by as much as a factor of 2 or more. The effects of these potential exposure uncertainties or shield thickness requirements are analyzed. Townsend, Lawrence W. and Nealy, John E. and Wilson, John W. and Simonsen, Lisa C. Langley Research Center NASA-TM-4167, L-16715, NAS 1.15:4167 RTOP 199-04-16-11...
Author: Judy L. Shinn
Publisher:
Published: 1992
Total Pages: 26
ISBN-13:
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Published: 1685
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DOWNLOAD EBOOKAuthor: United States. National Aeronautics and Space Administration Scientific and Technical Information Division
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Published: 1967
Total Pages: 2300
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DOWNLOAD EBOOKAuthor: United States. National Aeronautics and Space Administration. Scientific and Technical Information Division
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Published: 1966
Total Pages: 2088
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Published: 1994-04
Total Pages: 1200
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DOWNLOAD EBOOKAuthor: John W. Wilson
Publisher:
Published: 1997
Total Pages: 26
ISBN-13:
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