Study Of The Superconducting Multi-spoke Cavity

The accelerator of the Accelerator Driven System (ADS) for nuclear wastetransmutation is a high intensity CW proton beam facility based on thesuperconducting accelerating structures. The double spoke cavity is chose as analternative cavity for the medium energy section of the project. It is a technologypioneer research for the ADS project.The EM design of the325MHz β=0.52double spoke cavity for the project isstudied in this thesis. A parameter sweep is performed to optimize the double spokecavity. The final performance shows the cavity can satisfy the requirement of highgradient and large shunt impedance.The mechanical design, including the structure calculations and EM-Mechanicalcoupled simulations, provides the stiffening ribs to keep the strength and stability ofthe cavity. The fabrication arts and the mechanical tolerance of machining are alsoanalyzed.Finally，the multipacting property and beam kick effect due to the asymmetrictransverse field are studied in details. A3D EM field and particle tracking softwarehave been used to do the multipacting simulation. The methods for multipactingsuppression have also been studied. The beam kick effect due to the axial asymmetryof the spoke has been studied. The effect varies by changing the shape of the beampipe and spoke aperture has been presented as well.