Organ shielding and doses in Low-Earth orbit calculated for spherical and anthropomorphic phantoms

Matthiä, Daniel; Berger, Thomas; Reitz, Günther

doi:10.1016/j.asr.2013.03.025

Cited by 14 publications

(9 citation statements)

References 19 publications

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“…To estimate the dose rates and accumulated doses that would have been encountered in interplanetary space during the event, the above derived spectra have been used as primary input spectra to GEANT4 simulations using a spherical shielding geometry. The shielding consisted of an aluminum sphere with an inner radius of 200 cm and a thickness corresponding to 1 g/cm 2 (0.37 cm) and 30 g/cm 2 (11.1 cm) similar to Matthiä et al (). Particle fluxes inside this spherical geometry were used to calculate dose rates by applying fluence‐to‐dose conversion coefficients for a silicon detector with 300‐μm thickness and human organs.…”

Section: Calculated Radiation Exposures During the Eventmentioning

confidence: 99%

The Solar Particle Event on 10–13 September 2017: Spectral Reconstruction and Calculation of the Radiation Exposure in Aviation and Space

2018

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The solar energetic particle event on 10 September 2017 and on the following days was the strongest event in recent years. It was recorded as ground level enhancement 72 by neutron monitor stations on Earth and measured by a number of instruments in space. One aspect of such a space weather event is the potentially increased radiation exposure in aviation and space. Numerical simulations can help estimate the elevated dose rates during such an event; a critical aspect in these simulations is the description of the primary particle spectrum. In this work, we present 1-hr averaged proton spectra during the event derived from Geostationary Operational Environmental Satellite measurements and described by two different analytic functions. The derived proton spectra are used to calculate the radiation exposure in aviation and different space scenarios: low-Earth orbit, interplanetary space, and Mars surface, and the results are discussed in the context of available experimental data. While the results indicate that in most of these scenarios in aviation and space the event was of little significance compared to the total exposure from galactic cosmic radiation, the skin dose in a lightly shielded environment in interplanetary space may have reached about 30% to 60% of the NASA 30-day dose limit.

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Section: Calculated Radiation Exposures During the Eventmentioning

confidence: 99%

The Solar Particle Event on 10–13 September 2017: Spectral Reconstruction and Calculation of the Radiation Exposure in Aviation and Space

2018

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“…The career exposure limits for astronauts are defined for the effective dose, which is calculated as the sum of the dose equivalent in 15 critical organs (ICRP, 2007) multiplied by corresponding weighting factors. Out of 126 layers of our phantom we select 15 that correspond to critical organs following the procedure based on matching mean values of self‐shelding, as described in a study (Matthiä, Berger, & Reitz, 2013).…”

Section: Modeling Methodologymentioning

confidence: 99%

Beating 1 Sievert: Optimal Radiation Shielding of Astronauts on a Mission to Mars

et al. 2021

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Space radiation is one of the main concerns in planning long‐term human space missions. There are two main types of hazardous radiation: solar energetic particles (SEP) and galactic cosmic rays (GCR). The intensity and evolution of both depends on solar activity. GCR activity is most enhanced during solar minimum and lowest during solar maximum. The reduction of GCRs is alagging behind solar activity only by 6–12 month. SEP probability and intensity are maximized during solar maximum and are minimized during solar minimum. In this study, we combine models of the particle environment arising due to SEP and GCR with Monte Carlo simulations of radiation propagation inside a spacecraft and phantom. We include 28 fully ionized GCR elements from hydrogen to nickel and consider protons and nine ion species to model the SEP irradiation. Our calculations demonstrate that the optimal time for a flight to Mars would be launching the mission at solar maximum, and that the flight duration should not exceed approximately 4 years.

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“…The mean quality factors in selected organs, where PNTDs were applied, were calculated as the ratio between the total dose equivalent and the total organ dose (see Reitz et al ( 2009 ) for details). For the calculation of the mean quality factors in all remaining organs, an interpolation was performed using the Q values received by LET spectra measurement in the selected organs, applying the mean shielding depth for the organs of interest in the NUNDO phantom (Matthiä et al 2013 ).…”

Section: Methodsmentioning

confidence: 99%

NUNDO: a numerical model of a human torso phantom and its application to effective dose equivalent calculations for astronauts at the ISS

Puchalska

Bilski

Berger

et al. 2014

Radiat Environ Biophys

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The health effects of cosmic radiation on astronauts need to be precisely quantified and controlled. This task is important not only in perspective of the increasing human presence at the International Space Station (ISS), but also for the preparation of safe human missions beyond low earth orbit. From a radiation protection point of view, the baseline quantity for radiation risk assessment in space is the effective dose equivalent. The present work reports the first successful attempt of the experimental determination of the effective dose equivalent in space, both for extra-vehicular activity (EVA) and intra-vehicular activity (IVA). This was achieved using the anthropomorphic torso phantom RANDO® equipped with more than 6,000 passive thermoluminescent detectors and plastic nuclear track detectors, which have been exposed to cosmic radiation inside the European Space Agency MATROSHKA facility both outside and inside the ISS. In order to calculate the effective dose equivalent, a numerical model of the RANDO® phantom, based on computer tomography scans of the actual phantom, was developed. It was found that the effective dose equivalent rate during an EVA approaches 700 μSv/d, while during an IVA about 20 % lower values were observed. It is shown that the individual dose based on a personal dosimeter reading for an astronaut during IVA results in an overestimate of the effective dose equivalent of about 15 %, whereas under an EVA conditions the overestimate is more than 200 %. A personal dosemeter can therefore deliver quite good exposure records during IVA, but may overestimate the effective dose equivalent received during an EVA considerably.

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Organ shielding and doses in Low-Earth orbit calculated for spherical and anthropomorphic phantoms

Cited by 14 publications

References 19 publications

The Solar Particle Event on 10–13 September 2017: Spectral Reconstruction and Calculation of the Radiation Exposure in Aviation and Space

The Solar Particle Event on 10–13 September 2017: Spectral Reconstruction and Calculation of the Radiation Exposure in Aviation and Space

Beating 1 Sievert: Optimal Radiation Shielding of Astronauts on a Mission to Mars

NUNDO: a numerical model of a human torso phantom and its application to effective dose equivalent calculations for astronauts at the ISS

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