Updated deterministic radiation transport for future deep space missions

Slaba, Tony C.; Wilson, John W.; Werneth, Charles M.; Whitman, K.

doi:10.1016/j.lssr.2020.06.004

Cited by 23 publications

(14 citation statements)

References 42 publications

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“…Low energy processes associated with neutron‐hydrogen elastic recoils, negative pion capture, surface muons (produced from charged pions decaying after coming to rest in matter), and gamma production from nuclear de‐excitation are better characterized as well. Importantly, it was shown that the updated HZETRN code agrees almost identically with Monte Carlo simulation results in simple geometry (slabs and spheres) when the same nuclear interaction databases are used (Slaba et al., 2020).…”

Section: Models and Methodsmentioning

confidence: 80%

“…Also shown in panels (d) and (e) of Figure 4 are the results obtained from using Geant4 nuclear interaction cross section databases for nucleons and pions as described by Slaba et al. (2020). Effective doses calculated using Geant4 cross sections were found to be ∼7% smaller than those calculated using default nuclear cross section of HZETRN.…”

Section: Models and Methodsmentioning

confidence: 95%

“…Briefly, the HZETRN theoretical formalism is based on a converging sequence of physical approximations enabling computationally efficient numerical solutions to the Boltzmann transport equation (Wilson et al., 1991, 2014). Recent updates (Slaba et al., 2020) provided a fully coupled one‐dimensional (1D) and three‐dimensional (3D) transport code wherein pion interactions are fully coupled to the nucleon and light ion ( Z ≤ 2) fields. Low energy processes associated with neutron‐hydrogen elastic recoils, negative pion capture, surface muons (produced from charged pions decaying after coming to rest in matter), and gamma production from nuclear de‐excitation are better characterized as well.…”

Section: Models and Methodsmentioning

confidence: 99%

“…A Relativistic Abrasion‐Ablation De‐excitation FRaGmentation (RAADFRG) model (Werneth et al., 2021) able to describe nuclear structure effects seen in experimental data can be optionally used in place of the default NUCFRG3 (Adamczyk et al., 2012) model for heavy ion fragmentation. Finally, double‐differential nuclear interaction databases generated by external models, such as those included in Geant4 (Agostinelli et al., 2003), can now also be used within HZETRN (Slaba et al., 2020). The remainder of the nuclear interaction models have been described elsewhere (Wilson et al., 2014).…”

Section: Models and Methodsmentioning

confidence: 99%

“…Likewise, important advancements in nuclear physics (Norbury, 2021; Slaba et al., 2020; Werneth et al., 2021; Wilson et al., 2020) and radiation transport models (Slaba et al., 2020; Wilson et al., 2014) have been completed that contribute directly to astronaut risk projections for deep space missions. In particular, it has been shown that coupled pion‐nucleon interactions and the associated electromagnetic (EM) cascade make significant contributions to astronaut exposure behind spacecraft shielding (Slaba et al., 2020). These interactions are primarily initiated by high energy (>5 GeV/n) GCR ions that are minimally influenced by the state of the heliosphere.…”

Section: Introductionmentioning

confidence: 99%

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Historical Reconstruction of Astronaut Cancer Risk: Context for Recent Solar Minima

Slaba

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Human presence in space is expected to push beyond low Earth orbit (LEO) in the coming years with missions planned to the Moon and Mars (www.nasa.gov/what-is-artemis). In the absence of solar storms, astronaut radiation exposure will come from galactic cosmic rays (GCR) and accumulate proportionally with mission duration. Health effects from prolonged exposure to GCR have been extensively studied over the past several decades with significant uncertainties and knowledge gaps remaining in risk projections primarily due to lack of directly relevant human data and limited ground-based experimental data (Cucinotta et al., 2013; NASA 2013;Simonsen & Slaba, 2021).The GCR environment comprises a complex mixture of fully ionized and highly energetic particles capable of penetrating spacecraft shielding and producing a cascade of secondary particles such as neutrons. Hydrogen and helium ions account for 87% and 12% of the total GCR fluence by mass, respectively. The remaining 1% is covered by heavier ions with charge, Z, extending up to Z = 28 and beyond. The energy spectrum for each of these ions is quite broad with peak fluxes occurring just below 1 GeV/n and energies extending up to 1 TeV/n and beyond. GCR are modulated by the heliospheric magnetic field (HMF) on an approximate 11-year cycle. During solar minimum, the HMF is suppressed, and the flux of GCR ions below ∼5 GeV/n

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Section: Models and Methodsmentioning

confidence: 80%

Section: Models and Methodsmentioning

confidence: 95%