Transport Methods and Interactions for Space Radiations

John, Walter; Lawrence, W Townsend; Schimmerling, W.; Govind, S Khandelwal; Khan, Ferdous; John, E Nealy; Francis, A Cucinotta; Lisa, Cătălin; Judy, L Shinn

doi:10.1007/978-1-4615-2916-3_12

Cited by 119 publications

(254 citation statements)

References 410 publications

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“…(3), the correct value of LET for an ion of mass number, A, charge number, Z, and energy, E, is reproduced. The LET representations for ions described in [36] are used in the calculations described below. In the models of Chatterjee et al [30] and Waligorski et al [34], contributions from excitations are estimated.…”

Section: Energy Deposition In the Amorphous Track Modelmentioning

confidence: 99%

Applications of amorphous track models in radiation biology

Cucinotta

Nikjoo

Goodhead

1999

Radiation and Environmental Biophysics

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The average or amorphous track model uses the response of a system to gamma-rays and the radial distribution of dose about an ion's path to describe survival and other cellular endpoints from proton, heavy ion, and neutron irradiation. This model has been used for over 30 years to successfully fit many radiobiology data sets. We review several extensions of this approach that address objections to the original model, and consider applications of interest in radiobiology and space radiation risk assessment. In the light of present views of important cellular targets, the role of target size as manifested through the relative contributions from ion-kill (intra-track) and gamma-kill (inter-track) remains a critical question in understanding the success of the amorphous track model. Several variations of the amorphous model are discussed, including ones that consider the radial distribution of event-sizes rather than average electron dose, damage clusters rather than multiple targets, and a role for repair or damage processing.

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Section: Energy Deposition In the Amorphous Track Modelmentioning

confidence: 99%

Applications of amorphous track models in radiation biology

Cucinotta

Nikjoo

Goodhead

1999

Radiation and Environmental Biophysics

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“…We use life-tables (CDC, 2000) and background cancer mortality rates (SEER, 2000) for the average US population for the year 2000. For models we use the GCR free space environment of Badhwar et al (1994b), the HZETRN transport code (Wilson et al, 1991(Wilson et al, , 1995, and the QMSFRG model of nuclear fragmentation cross-sections . The CAMERA model (Billings and Yucker, 1973) is used for organ shielding with tissue weighting coefficients (NCRP, 2000).…”

Section: Resultsmentioning

confidence: 99%

“…Theoretical and computational efforts in the 1980's and 1990's have provided the basic understanding needed to design effective shielding approaches (Wilson et al, 1991, Cucinotta et al, 1998a. Materials of low atomic mass, especially hydrogen are expected to be optimal as radiation shields because they reduce the occurrence of secondary particles (neutrons, protons, and other recoils) and are more effective per unit mass of material in slowing down or stopping ions in atomic collisions, and fragmenting HZE ions.…”

Section: Introductionmentioning

confidence: 99%

Evaluating shielding effectiveness for reducing space radiation cancer risks

Cucinotta

Kim

Ren³

2006

Radiation Measurements

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129

116

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Abstract:We discuss calculations of probability distribution functions (PDF) representing uncertainties in projecting fatal cancer risk from galactic cosmic rays (GCR) and solar particle events (SPE). The PDF's are used in significance tests of the effectiveness of potential radiation shielding approaches. Uncertainties in risk coefficients determined from epidemiology data, dose and dose-rate reduction factors, quality factors, and physics models of radiation environments are considered in models of cancer risk PDF's. Competing mortality risks and functional correlations in radiation quality factor uncertainties are treated in the calculations. We show that the cancer risk uncertainty, defined as the ratio of the 95% confidence level (CL) to the point estimate is about 4-fold for lunar and Mars mission risk projections. For short-stay lunar missions (<180 d), SPE's present the most significant risk, however one that is mitigated effectively by shielding, especially for carbon composites structures with high hydrogen content. In contrast, for long duration lunar (>180 d) or Mars missions, GCR risks may exceed radiation risk limits, with 95% CL's exceeding 10% fatal risk for males and females on a Mars mission. For reducing GCR cancer risks, shielding materials are marginally effective because of the penetrating nature of GCR and secondary radiation produced in tissue by relativistic particles. At the present time, polyethylene or carbon composite shielding can not be shown to significantly reduce risk compared to aluminum shielding based on a significance test that accounts for radiobiology uncertainties in GCR risk projection.

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“…HZETRN (High Z and Energy TRaNsport, where Z is the charge) is a space radiation transport code currently used by NASA to characterize the space radiation environment inside spacecraft for human exposures [2,3,4]. It performs neutron, proton and heavy ion transport, but it does not take into account the production and transport of mesons, photons and leptons [4,5]. The question naturally arises as to how important these particles are with respect to space radiation problems.…”

Section: Introductionmentioning

confidence: 99%

Monte Carlo analysis of pion contribution to absorbed dose from Galactic cosmic rays

Aghara

Blattnig

Norbury

et al. 2009

Nuclear Instruments and Methods in Physics Research Section B:

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Accurate knowledge of the physics of interaction, particle production and transport is necessary to estimate the radiation damage to equipment used on spacecraft and the biological effects of space radiation. For long duration astronaut missions, both on the International Space Station and the planned manned missions to Moon and Mars, the shielding strategy must include a comprehensive knowledge of the secondary radiation environment. The distribution of absorbed dose and dose equivalent is a function of the type, energy and population of these secondary products. Galactic cosmic rays (GCR) comprised of protons and heavier nuclei have energies from a few MeV per nucleon to the ZeV region, with the spectra reaching flux maxima in the hundreds of MeV range. Therefore, the MeV -GeV region is most important for space radiation. Coincidentally, the pion production energy threshold is about 280 MeV. The question naturally arises as to how important these particles are with respect to space radiation problems. The space radiation transport code, HZETRN (High charge (Z) and Energy TRaNsport), currently used by NASA, performs neutron, proton and heavy ion transport explicitly, but it does not take into account the production and transport of mesons, photons and leptons. In

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Transport Methods and Interactions for Space Radiations

Cited by 119 publications

References 410 publications

Applications of amorphous track models in radiation biology

Applications of amorphous track models in radiation biology

Evaluating shielding effectiveness for reducing space radiation cancer risks

Monte Carlo analysis of pion contribution to absorbed dose from Galactic cosmic rays

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