Abstract
Passive radiation shielding alone is insufficient for protecting astronauts from galactic cosmic ray exposure. Active shields, utilizing electromagnetic fields to deflect heavy charged ions in space, could be used to supplement conventional passive shielding. Due to experimental limitations, simulation capability is crucial for designing effective active shields. The purpose of this work is to validate the Active Shielding Particle Pusher (ASPP) code, used to characterize active shielding efficacy, using beamline measurements conducted at the Brookhaven National Laboratory. Emphasis is placed on (1) comparing shielding efficacy as a function of a scaled dimensionless parameter among various electric dipole sphere sizes and center-to-center distances, (2) comparing shielding efficacy as a function of dipole rotation angle as the voltage applied to each sphere is varied independently, and (3) comparing shielding efficacy observed in measurements and simulations to broaden the validation domain of ASPP. Simulated and measured shielding efficacy data are shown to agree within a factor of 1.10 on average. The results of this work demonstrate that dimensionless scaling of parameters characteristic of the active shield and incident radiation can be used to create scaling laws for a range of ion species relevant for protecting astronauts from galactic cosmic ray exposure at beamline energies.
Highlights
The risks associated with space radiation on crewed, longduration, deep-space missions limit our ability to execute these missions beyond low-Earth orbit while remaining in compliance with applicable National Aeronautics and Space Administration (NASA) standards.1 Galactic cosmic rays (GCRs) and solar energetic particles (SEPs), which make up the bulk of the interplanetary radiation field capable of impacting astronaut health, are composed of highly energetic, heavy charged particles (HZEs).2 Mass requirements for astronaut radiation protection are too great for passive shielding alone to provide adequate protection
Emphasis is placed on (1) comparing shielding efficacy as a function of a scaled dimensionless parameter among various electric dipole sphere sizes and center-to-center distances, (2) comparing shielding efficacy as a function of dipole rotation angle as the voltage applied to each sphere is varied independently, and (3) comparing shielding efficacy observed in measurements and simulations to broaden the validation domain of Active Shielding Particle Pusher (ASPP)
The objectives of this work were to (1) compare shielding efficacy as a function of fs among various electric dipole sphere radii (a) and center-to-center distances between spheres (‘CC), (2) compare shielding efficacy as a function of dipole rotation angle (α) as the voltage applied to each sphere was varied independently, and (3) compare shielding efficacy observed in measurements vs analogous simulations in order to broaden the existing validation domain of the Active Shielding Particle Pusher (ASPP) code to include ion species relevant for protecting astronauts from galactic cosmic ray exposure
Summary
The risks associated with space radiation on crewed, longduration, deep-space missions limit our ability to execute these missions beyond low-Earth orbit while remaining in compliance with applicable National Aeronautics and Space Administration (NASA) standards. Galactic cosmic rays (GCRs) and solar energetic particles (SEPs), which make up the bulk of the interplanetary radiation field capable of impacting astronaut health, are composed of highly energetic, heavy charged particles (HZEs). Mass requirements for astronaut radiation protection are too great for passive shielding alone to provide adequate protection. Mass requirements for astronaut radiation protection are too great for passive shielding alone to provide adequate protection. GCRs, in particular, are capable of penetrating large material thicknesses, rendering practical passive shielding thicknesses ineffective for astronaut protection.. GCRs, in particular, are capable of penetrating large material thicknesses, rendering practical passive shielding thicknesses ineffective for astronaut protection.3,4 In response to these excessive mass requirements, efforts are underway to explore the applicability of active shielding to space radiation shielding problems. In contrast with passive shielding, which relies on the use of bulk material to reduce the energy of and potentially stop energetic particles, active shielding employs electromagnetic fields to shield incident charged particle radiation, either by slowing them down or diverting them away from the crew volume altogether
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