OLTARIS: On-line tool for the assessment of radiation in space

Singleterry, Robert C.; Blattnig, Steve R.; Clowdsley, M. S.; Qualls, Garry D.; Sandridge, Chris A.; Simonsen, Lisa C.; Slaba, Tony C.; Walker, Steven A.; Badavi, Mohammad; Spangler, Jan L.; Aumann, Aric R.; Zapp, E. Neal; Rutledge, Robert; Lee, Kerry T.; Norman, Ryan B.; Norbury, John W.

doi:10.1016/j.actaastro.2010.09.022

Cited by 102 publications

(76 citation statements)

References 22 publications

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“…Averaging over sols 13-173, we find an average u value of 577 MV. The results generated from HZETRN presented herein can also now be generated with the ''On-Line Tool for the Assessment of Radiation in Space'' (OLTARIS; Singleterry et al 2011), and are labeled as HZETRN/OLTARIS in the following plots and tables. The only exceptions are the photon, pion, muon, electron, and positron results which are not yet available through the website.…”

Section: Hzetrn/oltarismentioning

confidence: 99%

“…Several numerical models exist that can calculate the transport of primary nuclei from the GCR through the Martian atmosphere and the backscattering from the soil. The following models are investigated in this work: HZETRN/OLTARIS (Wilson et al 1991;Slaba et al 2010aSlaba et al , 2010bSlaba et al , 2013Singleterry et al 2011;Norman et al 2013), GEANT4/PLANETOCOSMICS (Agostinelli et al 2003;Allison et al 2006), and PHITS (Niita et al 2006;Sato et al 2013). These transport models, which are discussed in more detail below, have to be combined with models of the primary GCR spectra taking into account the solar modulation.…”

Section: Introductionmentioning

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: Introductionmentioning

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.

View full text Add to dashboard Cite

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“…The energy spectrum of these particles can extend up to the GeV/n range. A more detailed description of the environment models used in OLTARIS can be found in reference [1].…”

Section: Oltaris Overviewmentioning

confidence: 99%

“…This includes the differential flux/fluence spectrum, LET (Linear Energy Transfer) spectrum, dose in silicon, dose in tissue, TEPC (Tissue Equivalent Proportional Counter), dose equivalent using the ICRP (International Commission on Radiological Protection) 60 [8] LET dependent quality factor, and effective dose equivalent [9] using the human phantoms Computerized Anatomical Man (CAM) [10], Computerized Anatomical Female (CAF) [11,12], Male Adult voXel (MAX) MAX [13], or Female Adult voXel (FAX) [14]. More detailed discussion of the response functions on OLTARIS can be found in reference [1]. For the case of a slab, the selected response is computed at each layer interface and at the end of the slab.…”

Section: Oltaris Overviewmentioning

confidence: 99%

“…The high efficiency is particularly useful in the early design stages where mass distributions and shielding materials change often. In this paper, we discuss the On-Line Tool for the Assessment of Radiation in Space (OLTARIS), available at https://oltaris.nasa.gov [1]. This tool was developed specifically to provide rapid analysis of materials, shielding concepts, and geometry models in space radiation environments.…”

Section: Introductionmentioning

confidence: 99%

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OLTARIS: an efficient web-based tool for analyzing materials exposed to space radiation

et al. 2011

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The near-Earth space radiation environment includes energetic galactic cosmic rays (GCR), high intensity proton and electron belts, and the potential for solar particle events (SPE). These sources may penetrate shielding materials and deposit significant energy in sensitive electronic devices on board spacecraft and satellites. Material and design optimization methods may be used to reduce the exposure and extend the operational lifetime of individual components and systems. Since laboratory experiments are expensive and may not cover the range of particles and energies relevant for space applications, such optimization may be done computationally with efficient algorithms that include the various constraints placed on the component, system, or mission. In the present work, the web-based tool OLTARIS (On-Line Tool for the Assessment of Radiation in Space) is presented, and the applicability of the tool for rapidly analyzing exposure levels within either complicated shielding geometries or user-defined material slabs exposed to space radiation is demonstrated. An example approach for material optimization is also presented. Slabs of various advanced multifunctional materials are defined and exposed to several space radiation environments. The materials and thicknesses defining each layer in the slab are then systematically adjusted to arrive at an optimal slab configuration.

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Measurements of the neutron spectrum on the Martian surface with MSL/RAD

et al. 2014

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Curiosity, measures the energetic charged and neutral particles and the radiation dose rate on the surface of Mars. An important factor for determining the biological impact of the Martian surface radiation is the specific contribution of neutrons, with their deeper penetration depth and ensuing high biological effectiveness. This is very difficult to measure quantitatively, resulting in considerable uncertainties in the total radiation dose. In contrast to charged particles, neutral particles (neutrons and gamma rays) are generally only measured indirectly. Measured spectra are a complex convolution of the incident particle spectrum with the detector response function and must be unfolded. We apply an inversion method (based on a maximum likelihood estimation) to calculate the neutron and gamma spectra from the RAD neutral particle measurements. Here we show the first spectra on the surface of Mars and compare them to theoretical predictions. The measured neutron spectrum (ranging from 8 to 740 MeV) translates into a radiation dose rate of 14 ± 4 μGy/d and a dose equivalent rate of 61 ± 15 μSv/d. This corresponds to 7% of the measured total surface dose rate and 10% of the biologically relevant surface dose equivalent rate on Mars. Measuring the Martian neutron and gamma spectra is an essential step for determining the mutagenic influences to past or present life at or beneath the Martian surface as well as the radiation hazard for future human exploration, including the shielding design of a potential habitat.

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OLTARIS: On-line tool for the assessment of radiation in space

Cited by 102 publications

References 22 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

OLTARIS: an efficient web-based tool for analyzing materials exposed to space radiation

Measurements of the neutron spectrum on the Martian surface with MSL/RAD

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