Investigation of the hybrid multilayered higher-order-mode absorber at NSRL for a 499.8MHz superconducting cavity

This study investigates Beam Line Absorbers (BLAs) for the Hefei Advanced Light Facility (HALF). A ferrite-based BLA prototype was developed, demonstrating high-power handling capacity up to 10[Formula: see text]kW, ultra-high vacuum performance better than [Formula: see text] [Formula: see text]mbar, and high absorption efficiency in critical frequency ranges. Subsequently, more compact designs with reduced longitudinal length were explored, investigating ferrite-only, silicon carbide (SiC)-only, and hybrid configurations through RF simulations. Based on preferred absorption efficiency, ferrite-only and hybrid BLA structures were further analyzed under high-power conditions. Referencing test results, multiphysics simulations were conducted under 3[Formula: see text]kW absorbed power. The hybrid design, comprising two rings of ferrite tiles and one ring of SiC tiles, improved the temperature distribution of the absorbing materials. Extrapolating to 11[Formula: see text]kW absorbed power, this design reduced the maximum temperatures on absorbing tiles by up to 40[Formula: see text]C compared to the ferrite-only design. The hybrid design offers a balanced solution that combines effective HOM damping with enhanced thermal performance, improving the long-term operational stability of BLAs.