On Active Radiation Shielding Efficacy of a Point Design for Lunar Applications

We report on improvements to the simulation architecture and the resultant evaluations of the 3D point design of a highly charged electrode structure to enhance the shielding efficacy against solar energetic particles in a lunar habitat. The lunar infrastructure was enclosed by a half-sphere and a circular surface with a radius of 1km. A habitat was positioned at the plane's center with dimensions of 11.0x3.0x2.5m. The electrode structure, with dimensions of 131.4x131.4x80.7m, was set up around it, with these specific dimensions chosen to accommodate five anode stacks, each made up of four grids and four cathode antennas. The evaluation process was comprehensive. The first scenario, devoid of the electrode structure, was used to calibrate the particle injection and analyze the unobstructed particle deposition onto the surface. Considering the uncharged electrodes, the second scenario assessed material shielding effects. The third scenario, with the anode charged with +1MV and the cathode with −1MV, was designed to approximate the radiation shielding against protons, alpha particles, Fe6+ ions, and electrons of varying energies. For each particle species, the energy-weighted average shielding efficacy of the electrode setup was determined compared to the first scenario, leading to 70.7% for the protons with significant particle-reduced areas at low energies, 14.4% for the alpha-particles, and 6.5% for the Fe6+ ions. The obtained results indicate that a significant particle-reduced area was formed in the case of low-energy electrons, whereas ultra-relativistic electrons experienced a shielding efficacy of 21.7%. We will present the results of particle energy studies, which assess the potential impact damage and parametrization in the structure's geometry to maximize the shielding efficacy. These optimization studies are not just theoretical exercises but offer practical insight into the limitations of the current technologies for electrostatic radiation shielding of future lunar habitats, sparking further research and development in the field.