3DHZETRN: Shielded ICRU spherical phantom

Wilson, John W.; Slaba, Tony C.; Badavi, Mohammad; Reddell, Brandon; Bahadori, Amir A.

doi:10.1016/j.lssr.2015.01.002

Cited by 29 publications

(8 citation statements)

References 67 publications

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“…The pion, muon, and electromagnetic cascade components (Norman et al 2013) are also included here. Recent improvements to the code (Wilson et al 2014(Wilson et al , 2015 include 3D corrections for neutrons and light ions which were not included here but may be considered in future work. The NUCFRG3 (Adamczyk et al 2012) model is used for describing nuclear fragmentation of heavy ions.…”

Section: Hzetrn/oltarismentioning

confidence: 99%

“…This is caused in part by differing nuclear models as well as by the lack of 3D effects in this version of HZETRN. Future work could use the 3DHZETRN code (Wilson et al 2014(Wilson et al , 2015 to gauge the impact of 3D corrections for these atmospheric/surface scenarios. The tendency of all models to overestimate the measured proton spectra, especially at these energies, might also be attributable to uncertainties in the primary GCR spectrum and atmospheric composition and thickness.…”

Section: Charged Particle Spectramentioning

confidence: 99%

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The Martian surface radiation environment – a comparison of models and MSL/RAD measurements

Matthiä

Ehresmann

Lohf

et al. 2016

J. Space Weather Space Clim.

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Context: The Radiation Assessment Detector (RAD) on the Mars Science Laboratory (MSL) has been measuring the radiation environment on the surface of Mars since August 6th 2012. MSL-RAD is the first instrument to provide detailed information about charged and neutral particle spectra and dose rates on the Martian surface, and one of the primary objectives of the RAD investigation is to help improve and validate current radiation transport models. Aims: Applying different numerical transport models with boundary conditions derived from the MSL-RAD environment the goal of this work was to both provide predictions for the particle spectra and the radiation exposure on the Martian surface complementing the RAD sensitive range and, at the same time, validate the results with the experimental data, where applicable. Such validated models can be used to predict dose rates for future manned missions as well as for performing shield optimization studies. Methods: Several particle transport models (GEANT4, PHITS, HZETRN/OLTARIS) were used to predict the particle flux and the corresponding radiation environment caused by galactic cosmic radiation on Mars. From the calculated particle spectra the dose rates on the surface are estimated. Results: Calculations of particle spectra and dose rates induced by galactic cosmic radiation on the Martian surface are presented. Although good agreement is found in many cases for the different transport codes, GEANT4, PHITS, and HZETRN/OLTARIS, some models still show large, sometimes order of magnitude discrepancies in certain particle spectra. We have found that RAD data is helping to make better choices of input parameters and physical models. Elements of these validated models can be applied to more detailed studies on how the radiation environment is influenced by solar modulation, Martian atmosphere and soil, and changes due to the Martian seasonal pressure cycle. By extending the range of the calculated particle spectra with respect to the experimental data additional information about the radiation environment is gained, and the contribution of different particle species to the dose is estimated.

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Section: Hzetrn/oltarismentioning

confidence: 99%

Section: Charged Particle Spectramentioning

confidence: 99%

The Martian surface radiation environment – a comparison of models and MSL/RAD measurements

Matthiä

Ehresmann

Lohf

et al. 2016

J. Space Weather Space Clim.

Self Cite

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“…The comparison performed in this study doesn't show as good agreement as in previous comparisons, which have generally been done for proton only environments, such as solar particle events or GCR environments separately, but not combined. 15 This same prior work uses different sampling techniques for these two environment regimes because each environment spans different energy scales. Source energy biasing is desired for low energy proton spectra, such as that from solar particle events or trapped radiation, to improve neutron statistics, something that was not done in this study because the trapped protons were combined with the galactic cosmic ray proton spectra.…”

Section: Discussionmentioning

confidence: 99%

Comparison and Validation of FLUKA and HZETRN as Tools for Investigating the Secondary Neutron Production in Large Space Vehicles

Rojdev

Koontz

Reddell

et al. 2015

AIAA SPACE 2015 Conference and Exposition

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NASA's exploration goals are focused on deep space travel and Mars surface operations. To accomplish these goals, large structures will be necessary to transport crew and logistics in the initial stages, and NASA will need to keep the crew and the vehicle safe during transport and any surface activities. One of the major challenges of deep space travel is the space radiation environment and its impacts on the crew, the electronics, and the vehicle materials. The primary radiation from the sun (solar particle events) and from outside the solar system (galactic cosmic rays) interact with materials of the vehicle. These interactions lead to some of the primary radiation being absorbed, being modified, or producing secondary radiation (primarily neutrons). With all vehicles, the high energy primary radiation is of most concern. However, with larger vehicles that have large shielding masses, there is more opportunity for secondary radiation production, and this secondary radiation can be significant enough to cause concern. When considering surface operations, there is also a secondary radiation source from the surface of the planet, known as albedo, with neutrons being one of the most significant species. Given new vehicle designs for deep space and Mars missions, the secondary radiation environment and the implications of that environment is currently not well understood. Thus, several studies are necessary to fill the knowledge gaps of this secondary radiation environment. In this paper, we put forth the initial steps to increasing our understanding of neutron production from large vehicles by comparing the neutron production resulting from our radiation transport codes and providing a preliminary validation of our results against flight data. This paper will review the details of these results and discuss the finer points of the analysis. Nomenclature GCR = galactic cosmic radiation SPE = solar particle event

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“…It allows the geometry configurations to be specified as slabs, spheres, or complicated spacecraft, habitat, exploration vehicles and space suits [18]. HZETRN 2015 is the deterministic transport code developed at NASA Langley Research Center [9][10][11][12][13][14][15][16]. The HZETRN code is he engine behind Tool for the Assessment of Radiation in Space (TARIS) which is a deterministic space radiation analysis tool.…”

Section: Gcr Modelsmentioning

confidence: 99%

“…For this study, we used OLTARIS [8] and HZETRAN 2015 [9][10][11][12][13][14][15][16] to simulate dose equivalent in mSv/year for various materials with various thickness in g/cm 2 . The simulation was performed using 2010 solar minimum GCR space radiation environment [16].…”

Section: Introductionmentioning

confidence: 99%

Evaluating Shielding Materials for High Energy Space Radiation

Gohel

Makwana

Soni

2022

IOP Conf. Ser.: Mater. Sci. Eng.

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Space radiation is very hazardously harmful to human health and physically damaging to electronics equipment. The major radiation sources are Solar Particle Events (SPE) and Galactic Cosmic Rays/Radiation (GCR). GCR composed of high energy protons, alpha particles and electrons travelling from outside solar system are especially difficult to shield. Previous study has been shown that aluminum and higher atomic number structural alloys, provide fairly little shielding which may increase secondary radiation. In this work, we evaluate the range of materials for GCR shielding. Materials are aluminum, for its low atomic number, Liquid Hydrogen, Polyethylene,Water, Polybenzoxazine, Lithium hydride, Liquid Methane and Hydrogenated Graphite Nano fiber (HGNF) materials which containing high proportions of hydrogen which effectively slowing secondary neutrons and GCR radiation. Boron nitride storing hydrogen absorbs the secondary neutrons, GCR, and SPE effectively. Liquid Methane performance is also noticeable. The dose equivalent for each shielding materials are calculated using On-line Tool for the Assessment of Radiation In Space (OLTARIS) and High Charge and Energy TRaNsport (HZETRN) and compared for 2010 Solar minimum GCR. The results show that Liquid hydrogen is the good space radiation shielding material for a given thickness, followed by Lithium Hydride, Liquid Methane, Boron nitride storing hydrogen, Polyethylene, Polybenzoxazine, HGNF, and then aluminum. In addition, we plotted dose equivalent for Liquid hydrogen and Polyethylene at different densities.

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3DHZETRN: Shielded ICRU spherical phantom

Cited by 29 publications

References 67 publications

The Martian surface radiation environment – a comparison of models and MSL/RAD measurements

The Martian surface radiation environment – a comparison of models and MSL/RAD measurements

Comparison and Validation of FLUKA and HZETRN as Tools for Investigating the Secondary Neutron Production in Large Space Vehicles

Evaluating Shielding Materials for High Energy Space Radiation

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