Mitigating the Effects of the Space Radiation Environment: A Novel Approach of Using Graded-Z Materials

Atwell, William; Rojdev, Kristina; Aghara, Sukesh K.; Sriprisan, Sirikul

doi:10.2514/6.2013-5385

Cited by 12 publications

(9 citation statements)

References 2 publications

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“…Alternatively, it may be possible to replicate a solenoid field using a ring of magnets for each solenoid similar to that used by primary particle magnetic diverters in existing missions 23 . While passive magnetic shielding like this would remove the power requirements of generating such a magnetic field, the magnets may need to be graded-Z shielded 24 to ensure that fluorescence from high atomic number materials in the magnets does not influence the detector background (although this might also have to be done in the case of copper solenoids).…”

Section: Full Cosmic Ray Proton Spectrum Simulation Resultsmentioning

confidence: 99%

Effectiveness of a dual solenoid magnetic shield at reducing x-ray-like background in silicon-based x-ray detectors

Davis

Hall

2023

J. Astron. Telesc. Instrum. Syst.

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.Magnetic shielding has been used during past and current x-ray astronomy missions to shield detectors from electrons entering through telescope optics, and soft proton diverters have also been planned for future missions. However, simulations performed throughout the past decade have discovered that a significant proportion of x-ray-like background originates from secondary electrons produced in spacecraft shielding surrounding x-ray detectors, which hit detectors isotropically from all directions. Here, the results from Geant4 simulations of a simple dual solenoid magnetic field surrounding a 450 μm thick detector with several on-chip layers based on the structure of preliminary designs for the ATHENA Wide Field Imager are presented. We found that for a magnetic field strength at the middle between the two coils of equal to or greater than ∼12 mT, a dual solenoid magnetic field is extremely effective at preventing secondary electrons depositing between 2 and 7 keV and induced by galactic cosmic protons from reaching the detector. While the exact level of background reduction would depend on specific spacecraft and detector design, this magnetic shielding method could remove almost all background associated with backscattering and absorbed electrons, which are expected to account for approximately two thirds of the expected off-axis background in silicon-based x-ray detectors of several hundred microns in thickness and would likely be even more effective for thinner detectors where x-ray-like background is even more dominated by electrons. The magnetic field structure necessary for doing this could be produced using a set of solenoids or neodymium magnets providing that power requirements can be sufficiently optimized or neodymium fluorescence lines can be sufficiently attenuated, respectively. Testing would also have to be done to ensure that detectors it is used on are sufficiently magnetically hard; for context, the current limit for magnetic field strength around the ATHENA Wide Field Imager is 1 mT although CCD97s, another type of space-based x-ray detector, are magnetically hard at least above 6.4 mT.

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Section: Full Cosmic Ray Proton Spectrum Simulation Resultsmentioning

confidence: 99%

Effectiveness of a dual solenoid magnetic shield at reducing x-ray-like background in silicon-based x-ray detectors

Davis

Hall

2023

J. Astron. Telesc. Instrum. Syst.

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“…The outer higher-Z layers scatter electrons and protons and absorbs gamma rays, this subsequently results in x-ray fluorescence which is absorbed by deeper layers to attenuate it to a reasonable level. This technology has been demonstrated to reduce electron penetration by up to 60% in comparison to the same mass of single material shielding, and hence can be highly effective trapped electron mitigators between Medium Earth Orbit (MEO) and GEO [66]. Launched in December 2018, Shields-1, a 3U CubeSat demonstration, aims to enhance the Technology Readiness Level (TRL) of this radiation shielding for CubeSats from proof of concept at TRL 3 to TRL 6, demonstration in space.…”

Section: Discussionmentioning

confidence: 99%

Contemporaneous Monitoring of the Whole Dynamic Earth System from Space, Part I: System Simulation Study Using GEO and Molniya Orbits

Cullingworth

Müller²

2021

Remote Sensing

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Despite the wealth of data produced by previous and current Earth Observation platforms feeding climate models, weather forecasts, disaster monitoring services and countless other applications, the public still lacks the ability to access a live, true colour, global view of our planet, and nudge them towards a realisation of its fragility. The ideas behind commercialization of Earth photography from space has long been dominated by the analytical value of the imagery. What specific knowledge and actionable intelligence can be garnered from these evermore frequent revisits of the planet’s surface? How can I find a market for this analysis? However, what is rarely considered is what is the educational value of the imagery? As students and children become more aware of our several decades of advance in viewing our current planetary state, we should find mechanisms which serve their curiosity, helping to satisfy our children’s simple quest to explore and learn more about what they are seeing. The following study describes the reasons why current GEO and LEO observation platforms are inadequate to provide truly global RGB coverage on an update time-scale of 5-min and proposes an alternative, low-cost, GEO + Molniya 3U CubeSat constellation to perform such an application.

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“…Aluminum layers have been thoroughly used as shielding, but Z-graded shields have also proven to perform with a reduced mass compared to Aluminum layers. The NASA Shields-1 technology demonstrator [20] seeks to test Z-graded shielding technology (a laminate of several materials with different atomic numbers, designed to protect against ionizing radiation) [21] in a CubeSat with the corresponding limitations in both mass and available room. SPENVIS [22] has been used to perform the radiation analysis, mainly focusing on trapped proton and electron fluxes, galactic cosmic ray fluxes, and damage equivalent fluencies for solar cells.…”

Section: Methodsmentioning

confidence: 99%

3Cat-3/MOTS Nanosatellite Mission for Optical Multispectral and GNSS-R Earth Observation: Concept and Analysis

Castellví

Camps

Corbera

et al. 2018

Sensors

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The 3Cat-3/MOTS (3: Cube, Cat: Catalunya, 3: 3rd CubeSat mission/Missió Observació Terra Satèl·lit) mission is a joint initiative between the Institut Cartogràfic i Geològic de Catalunya (ICGC) and the Universitat Politècnica de Catalunya-BarcelonaTech (UPC) to foster innovative Earth Observation (EO) techniques based on data fusion of Global Navigation Satellite Systems Reflectometry (GNSS-R) and optical payloads. It is based on a 6U CubeSat platform, roughly a 10 cm × 20 cm × 30 cm parallelepiped. Since 2012, there has been a fast growing trend to use small satellites, especially nanosatellites, and in particular those following the CubeSat form factor. Small satellites possess intrinsic advantages over larger platforms in terms of cost, flexibility, and scalability, and may also enable constellations, trains, federations, or fractionated satellites or payloads based on a large number of individual satellites at an affordable cost. This work summarizes the mission analysis of 3Cat-3/MOTS, including its payload results, power budget (PB), thermal budget (TB), and data budget (DB). This mission analysis is addressed to transform EO data into territorial climate variables (soil moisture and land cover change) at the best possible achievable spatio-temporal resolution.

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Mitigating the Effects of the Space Radiation Environment: A Novel Approach of Using Graded-Z Materials

Cited by 12 publications

References 2 publications

Effectiveness of a dual solenoid magnetic shield at reducing x-ray-like background in silicon-based x-ray detectors

Effectiveness of a dual solenoid magnetic shield at reducing x-ray-like background in silicon-based x-ray detectors

Contemporaneous Monitoring of the Whole Dynamic Earth System from Space, Part I: System Simulation Study Using GEO and Molniya Orbits

3Cat-3/MOTS Nanosatellite Mission for Optical Multispectral and GNSS-R Earth Observation: Concept and Analysis

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