Long-Term Radiation Rugged Rotary Vacuum and Water Seals in Heavy-Ion Accelerators, Topic 26F

The Nuclear Physics community has identified a need for materials that will survive high radiation environments to support next generation rare isotope beam facilities. Specifically, long-lifetime, rotary vacuum and water seals are needed to survive 0.5 – 15 MGy/month. Current gaskets and seals do not offer the combined mechanical and radiation survivability needed for years of service, and organic paraffin ferrofluidic carriers break down at doses of ~2MGy. The objective of Phase I and II of this program is to develop and demonstrate advanced rotary vacuum and water seals with extreme radiation durability. The approach involves the synthesis of innovative non-fluorinated polymers within unique housing that do not evolve HF and offer low air and water permeability with extreme radiation durability. In Phase II, advanced polymer graded-z nanocomposites based on BN and Au were developed and exposed to harsh irradiation alongside candidate commercial seal materials for a durability study to reach a Technology Readiness Level 5. Mechanical, thermal, and thermomechanical testing were conducted prior to and post irradiation on a representative rotating shaft. Hardness values are being tailored to address that of the base rotating shaft within the beam dump. Materials have been down-selected and irradiated again to elucidate the mechanism for the radiation durability observed in the current Phase II study recently presented to the nuclear physics community. A down-selected set of polymers shall be irradiated under harsh radiation up to 600 kGy, and then under conditions representative of the rare isotope beam facility in the Linac Isotope Producer, up to 2 MGy. New noble metal nanoparticle coated ferrofluidic seals shall also be explored to address breakdown previously observed in organic paraffin-based carrier fluids. Seal prototypes shall be formed and integrated within a commercial parters’ housing design. Technology Readiness Level 7 shall be reached via experiments in a representative rare isotope high radiation environment. Radiation durable rotary vacuum and water seals shall be manufactured for use with rare isotope beam facilities for the stable production of new and rare isotopes. These isotopes shall benefit advanced imaging needs within the medical community. Many dual-use applications are being explored for space, military, and nuclear energy markets.