Shielding evaluation for solar particle events using MCNPX, PHITS and OLTARIS codes

Aghara, Sukesh K.; Sriprisan, Sirikul; Singleterry, Robert C.; Sato, Tatsuhiko

doi:10.1016/j.lssr.2014.12.003

Cited by 26 publications

(25 citation statements)

References 46 publications

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“…The abundance of GCRs by Z reflects the cosmic abundance of elements. By far the most abundant component is hydrogen nuclei or protons (numerically about 85%) followed by helium nuclei (about 13%) followed by other elements up to iron (Z ¼ 26) with even-numbered elements such as 12 C, 16 O and 28 Si being more abundant than odd-numbered elements (5). Recent GCR composition data in several energy bands is available at the project website of the Advanced Composition Explorer (ACE) satellite which orbits about 1.5 3 10 6 km sunward of Earth, near the gravitationally-stable L1 Lagrange point (6).…”

Section: Galactic Cosmic Raysmentioning

confidence: 99%

Space Radiation and Human Exposures, A Primer

2016

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Section: Galactic Cosmic Raysmentioning

confidence: 99%

Space Radiation and Human Exposures, A Primer

2016

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“…The physics of SEP radiation transport is different than the physics for GCR transport. However, comparisons of dosimetric quantities between HZETRN and several Monte Carlo transport codes, for various historical SEP events behind typical vehicle shielding, have shown that HZETRN differs from the other transport codes by less than 30% (Aghara et al, ). Therefore, it is reasonable to assess the total uncertainty in the SEP organ dose model by computing the root sum square of the 30% error in the HZETRN transport simulations and the errors in inferring the storm shelter organ doses from the vehicle dosimeter measurements presented in the analysis below.…”

Section: Resultsmentioning

confidence: 99%

Active Dosimeter‐Based Estimate of Astronaut Acute Radiation Risk for Real‐Time Solar Energetic Particle Events

Mertens

Slaba

2018

Space Weather

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Radiation exposure from solar energetic particle (SEP) events becomes a much greater concern as human exploration extends beyond low Earth orbit and the protective environment of Earth's magnetic field. Free‐space SEP events have an increased impact on mission planning and operations, as countermeasures may be necessary to avoid exceeding astronaut permissible exposure limits. Operational analysis tools are needed to assess acute radiation risk during SEP events in order to determine courses of action during the mission. A methodology has been developed to meet this need, which utilizes onboard vehicle dosimeter measurements to estimate organ dosimetric quantities at astronaut crew locations in real time. The estimated organ doses provide the necessary inputs to acute biological response models that predict radiation‐induced performance decrement and other acute radiation effects. The real‐time SEP organ dose estimation methodology has been combined with an acute biological response model, providing an active dosimeter‐based acute radiation risk model for operational mission planning, and determining radiation exposure mitigation measures for deep‐space exploration missions. This new tool has been developed specifically for National Aeronautics and Space Administration's Orion Multi‐Purpose Crew Vehicle storm shelter environment but could easily be extended to other vehicles. The methodology for estimating SEP organ doses is evaluated and assessed in this paper, and a simulation of the acute radiation responses in the Multi‐Purpose Crew Vehicle storm shelter is shown for the historical October 1989 SEP event. The operational acute radiation risk model will be utilized on National Aeronautics and Space Administration's Exploration Mission 1 and Exploration Mission 2.

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“…MeV/amu, ionization processes release electrons energetic enough to cause further ionization of nearby atoms and these electrons, having energies more than 1 MeV, are called δ-rays. The lateral spread of δ-rays is called track-width, which depends on velocity (energy) of the original particle and its atomic number according to the following ratio: (Z/β) 2 , where β is the particle velocity scaled to the speed of light. Figure 5 clearly showing the increasing lateral spread of δ-rays along the track with increasing the charge Z [6].…”

Section: Principals Of High Energy Particle Interaction With Mattermentioning

confidence: 99%

“…Transport codes characterize the modified radiation field downstream of the point of interaction between the incident radiation and the target nuclei. This characterization is in terms of absorbed dose or dose equivalent which is necessary to assess the response of electronics or, more importantly, biological systems [2]. Every transport code utilizes one of the two methods: analytic and probabilistic (Monte Carlo method).…”

Section: Transport Codesmentioning

confidence: 99%

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Evaluation of Efficiency of Various Materials to Shield From Radiation in Space Using the Monte Carlo Transport Code Called FLUKA

Savinov¹

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The purpose of this study is to improve spacecraft shielding from radiation in space. It focuses on the evaluation of shielding efficiency of different materials. The efficiency of a shield is evaluated by the dose profile within the shield and the amount of dose absorbed by a target using the Monte Carlo transport code called FLUKA. The output of this code is validated by recreating the experiments from published papers and comparing the results. Once the FLUKA's output is validated, the efficiency of sixteen materials, subject to SPE and GCR sources, are evaluated. The efficiency comparison is made by fixing the area density of a shield.It was found that polyethylene, water, carbon and silicon outperform aluminum -the primary metal used in spacecraft. In case of composite shield, made of layers of different materials, the 3Carb-9Al combination has better performance than the shield made just of aluminum. This holds true for both Solar Particle Events (SPEs) and Galactic Cosmic Ray (GCR). However, the choice of material is more efficient at shielding from SPE particles rather than from GCR. In case of GCR, the choice of materials is found to have rather small effect on the efficiency of a shield. The percent difference between the rate of dose absorption by a target, shielded by different materials, is within about 9%. Secondary particles make a significant contribution to the target's dose. For SPEs, the secondary particles are primarily electrons and neutrons. For GCRs, the secondary particles are primarily pions, α-particles and electrons. Protons contribute more than 50% to the target's dose in both cases. v ACKNOWLEDGMENTS

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Shielding evaluation for solar particle events using MCNPX, PHITS and OLTARIS codes

Cited by 26 publications

References 46 publications

Space Radiation and Human Exposures, A Primer

Space Radiation and Human Exposures, A Primer

Active Dosimeter‐Based Estimate of Astronaut Acute Radiation Risk for Real‐Time Solar Energetic Particle Events

Evaluation of Efficiency of Various Materials to Shield From Radiation in Space Using the Monte Carlo Transport Code Called FLUKA

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