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collection:
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nasa new
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nasa new
collection
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mediatype:
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texts
mediatype
texts
mediatype
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collection:
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nasa_techdocs
collection
nasa_techdocs
collection
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title:
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Measurement of Charged Particle Interactions in Spacecraft and Planetary Habitat Shielding Materials
title
Measurement of Charged Particle Interactions in Spacecraft and Planetary Habitat Shielding Materials
title
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description:
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Accurate models of health risks to astronauts on long-duration missions outside the geomagnetosphere will require a full understanding of the radiation environment inside a spacecraft or planetary habitat. This in turn requires detailed knowledge of the flux of incident particles and their propagation through matter, including the nuclear interactions of heavy ions that are a part of the Galactic Cosmic Radiation (GCR). The most important ions are likely to be iron, silicon, oxygen, and carbon. Transport of heavy ions through complex shielding materials including self-shielding of tissue modifies the radiation field at points of interest (e.g., at the blood-forming organs). The incident flux is changed by two types of interactions: (1) ionization energy loss, which results in reduced particle velocity and higher LET (Linear Energy Transfer); and (2) nuclear interactions that fragment the incident nuclei into less massive ions. Ionization energy loss is well understood, nuclear interactions less so. Thus studies of nuclear fragmentation at GCR-like energies are needed to fill the large gaps that currently exist in the database. These can be done at only a few accelerator facilities where appropriate beams are available. Here we report results from experiments performed at the Brookhaven National Laboratory s Alternating Gradient Synchrotron (AGS) and the Heavy Ion Medical Accelerator in Chiba, Japan (HIMAC). Recent efforts have focused on extracting charge-changing and fragment production cross sections from silicon beams at 400, 600, and 1200 MeV/nucleon. Some energy dependence is observed in the fragment production cross sections, and as in other data sets the production of fragments with even charge numbers is enhanced relative to those with odd charge numbers. These data are compared to the NASA-LaRC model NUCFRG2. The charge-changing cross section data are compared to recent calculations using an improved model due to Tripathi, which accurately predicts the observed (slight) energy dependence. An additional set of data will be presented from an analysis of shielding material performance in the 1 GeV/nucleon iron beam at the AGS. A wide variety of candidate materials for spacecraft construction, as well as elemental targets, have been placed in this beam and their effects on transmitted dose and dose equivalent measured. The results support a prediction by J. Wilson et al. that hydrogen-loaded materials give the greatest dose reduction per unit mass.
description
Accurate models of health risks to astronauts on long-duration missions outside the geomagnetosphere will require a full understanding of the radiation environment inside a spacecraft or planetary habitat. This in turn requires detailed knowledge of the flux of incident particles and their propagation through matter, including the nuclear interactions of heavy ions that are a part of the Galactic Cosmic Radiation (GCR). The most important ions are likely to be iron, silicon, oxygen, and carbon. Transport of heavy ions through complex shielding materials including self-shielding of tissue modifies the radiation field at points of interest (e.g., at the blood-forming organs). The incident flux is changed by two types of interactions: (1) ionization energy loss, which results in reduced particle velocity and higher LET (Linear Energy Transfer); and (2) nuclear interactions that fragment the incident nuclei into less massive ions. Ionization energy loss is well understood, nuclear interactions less so. Thus studies of nuclear fragmentation at GCR-like energies are needed to fill the large gaps that currently exist in the database. These can be done at only a few accelerator facilities where appropriate beams are available. Here we report results from experiments performed at the Brookhaven National Laboratory s Alternating Gradient Synchrotron (AGS) and the Heavy Ion Medical Accelerator in Chiba, Japan (HIMAC). Recent efforts have focused on extracting charge-changing and fragment production cross sections from silicon beams at 400, 600, and 1200 MeV/nucleon. Some energy dependence is observed in the fragment production cross sections, and as in other data sets the production of fragments with even charge numbers is enhanced relative to those with odd charge numbers. These data are compared to the NASA-LaRC model NUCFRG2. The charge-changing cross section data are compared to recent calculations using an improved model due to Tripathi, which accurately predicts the observed (slight) energy dependence. An additional set of data will be presented from an analysis of shielding material performance in the 1 GeV/nucleon iron beam at the AGS. A wide variety of candidate materials for spacecraft construction, as well as elemental targets, have been placed in this beam and their effects on transmitted dose and dose equivalent measured. The results support a prediction by J. Wilson et al. that hydrogen-loaded materials give the greatest dose reduction per unit mass.
description
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subject:
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STELLAR ENVELOPES
subject
STELLAR ENVELOPES
subject
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subject:
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CARBON
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subject:
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SPECTROSCOPY
subject
SPECTROSCOPY
subject
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subject:
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EXOBIOLOGY
subject
EXOBIOLOGY
subject
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subject:
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PROGRESS
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subject:
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STAR FORMATION
subject
STAR FORMATION
subject
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subject:
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PLANETARY SYSTEMS
subject
PLANETARY SYSTEMS
subject
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subject:
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BIOCHEMISTRY
subject
BIOCHEMISTRY
subject
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subject:
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ABIOGENESIS
subject
ABIOGENESIS
subject
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identifier:
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nasa_techdoc_2003006 0588
identifier
nasa_techdoc_2003006 0588
identifier
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licenseurl:
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uploader:
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gwilliam@archive.org
uploader
gwilliam@archive.org
uploader
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addeddate:
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2011-06-01 02:57:00
addeddate
2011-06-01 02:57:00
addeddate
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publicdate:
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2011-06-01 02:57:00
publicdate
2011-06-01 02:57:00
publicdate
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creator:
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Wilson, John W.
creator
Wilson, John W.
creator
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creator:
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Zeitlin, Cary J.
creator
Zeitlin, Cary J.
creator
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creator:
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Heilbronn, Lawrence H.
creator
Heilbronn, Lawrence H.
creator
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creator:
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Miller, Jack
creator
Miller, Jack
creator
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creator:
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Singleterry, Robert C., Jr
creator
Singleterry, Robert C., Jr
creator
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ImageUID:
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file:/home/lunaadmin /Source_download/201 106/1/nasa_techdoc_2 0030060588/200300605 88.pdf
ImageUID
file:/home/lunaadmin /Source_download/201 106/1/nasa_techdoc_2 0030060588/200300605 88.pdf
ImageUID
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date:
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2003-02-01
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rights:
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Public Domain
rights
Public Domain
rights
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ppi:
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300
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year:
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2003
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language:
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eng
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document-source:
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CASI
document_source
CASI
document-source
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documentid:
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20030060588
documentid
20030060588
documentid
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nasa-center:
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Langley Research Center
nasa_center
Langley Research Center
nasa-center
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online-source:
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http://wayback.archi ve-it.org/1792/20100 210052406/http://hdl .handle.net/2060/200 30060588
online_source
http://wayback.archi ve-it.org/1792/20100 210052406/http://hdl .handle.net/2060/200 30060588
online-source
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original-nasa-rights:
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Unclassified; No Copyright; Unlimited; Publicly available; Final Report
original_nasa_rights
Unclassified; No Copyright; Unlimited; Publicly available; Final Report
original-nasa-rights
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updated-added-to-ntrs:
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2008-06-02
updated_added_to_ntr s
2008-06-02
updated-added-to-ntr s
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contributor:
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NASA
contributor
NASA
contributor
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identifier-access:
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identifier_access
identifier-access
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identifier-ark:
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ark:/13960/t71v6d542
identifier_ark
ark:/13960/t71v6d542
identifier-ark
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ocr:
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ABBYY FineReader 8.0
ocr
ABBYY FineReader 8.0
ocr
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repub_state:
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4
repub_state
4
repub_state
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