Radiation Shielding of Electronic Circuits

Ionizing radiation sources, including primary particles such as energetic electrons, protons, and gamma rays, as well as secondary particles like thermal neutrons, are abundant at locations where space missions are often conducted, such as the low Earth orbit (LEO) and the Martian surface. Space radiation could severely damage human tissues and electronic components, presenting a risk factor for space explorations. Traditionally, high-Z number materials, primarily metals such as lead and aluminum, have been employed to attenuate space radiation. Due to the considerably high costs of transporting materials and equipment to space, low-density shielding materials based on polymer composites improve cost-effectiveness due to their lightweight nature, allowing for comparable radiation protection at a lower transportation cost. The miniaturization of satellite systems has compounded the need to protect microelectronic components from damaging radiation. Current approaches to mitigate this damage, such as indiscriminate mass shielding, built-in redundancies, and radiation hardened electronics, introduce high SWaP-C (Size, Weight, and Power-Cost) penalties that reduce the overall performance of the satellite. Additive manufacturing provides an appealing strategy to print radiation shielding only on susceptible components within an electronic assembly. In this Phase proposal, Vuronyx Technologies will collaborate with Dr. Bradley Duncan at MIT Lincoln Laboratory to further develop an additive manufacturing technology for radiation shielding. Preliminary experimental results reveal promising material candidates for this multifunctional material, and the structure could be further optimized for superior performance. The insights gained from this study present significant opportunities for future research and developments in the field of space exploration with architectured materials tailored for specific applications. Utilizing direct ink writing, we are able to conformally print customized inks at room temperatures directly and selectively onto COTS (commercial-of-the-shelf) electronics. The suite of inks uses a flexible styrene-isoprene- styrene block copolymer binder that can be filled with particles of varying atomic densities for varying radiation shielding capabilities. Additionally, blended composites of both high and low Z fillers were created to investigate the performance in radiation attenuation depending on composition. We anticipate this low SWaP-C alternative to traditional shielding methods will enable the development of novel complex and compact satellite designs.