Research on the structural optimization of a 120 keV positive ion source accelerator

[Background] The insulation supports for positive ion source accelerators are typically composed of epoxy resin bonding or PEEK with fluoro-rubber seal ring structure. There are issues with tritium permeation and neutron irradiation caused by high-energy, high-current ion beam injection during the operational phase of nuclear fusion reactors.[Purpose] This study aims to analyze the optimized accelerator structure in terms of high-pressure and mechanical performance characteristics.The design modifies the original insulator to Al₂O₃ ceramic structure. This configuration meets the high-voltage, mechanical strength, and vacuum sealing requirements for ion source operation. [Methods] The paper introduces the design of the new accelerator and conducts a mechanical analysis of the accelerator. The insulating components of the accelerator were replaced with PEEK material, followed by a complete structural redesign. Theoretical calculations and structural simulations of the new model ensured compliance with mechanical performance requirements. Subsequently, a pressure resistance analysis was conducted to verify the structure's capability to withstand high-voltage conditions. Finally, strength testing confirmed the overall structure met all specifications.The maximum normal stress on the bolts at the flange connection surface of the SG insulation is 50.393 MPa, and the shear force is 2.468 MPa. Through finite element analysis, the maximum normal stress calculated was 49.541 MPa, which differed from the theoretical value by 1.69%. The maximum shear force was 2.694 MPa, which differed from the theoretical solution by 8.38%. [Results] Through computational analysis, it has been determined that the maximum normal stress on the bolts at the flange connection surface of the SG insulation was 50.393 MPa, and the shear force was 2.468 MPa. Through finite element analysis, the maximum normal stress calculated was 49.541 MPa, which differed from the theoretical value by 1.69 %. The maximum shear force was 2.694 MPa, which differed from the theoretical solution by 8.38 %. The simulation and analysis results indicated that the stress on bolts on SG ceramic insulators was far less than the material strength of 304 stainless steel. [Conclusions] By electrostatic simulation and tensile strength testing of Al2O3 ceramic materials and models, the results show that the mechanical properties of the new accelerator structure meet the design requirements.