Concept Design of a New Structure of 1.3GHz Single-Cell Superconducting Cavities

Abstract：

This paper reports on a new design of single-cell superconducting cavities. It consists of two half-end cells of the 9-cell Beijing TESLA shape accelerating cavity. The ratio of the maximal surface electric field to accelerating gradient, E_p/E_acc, of the π mode of the 9-cell cavity was reduced to 2.024. The cell-to-cell coupling k is as high as 1.95%. The E_p/E_acc in the single-cell cavities was reduced to 1.8. The monopole, dipole, and quadrupole high-order modes (HOMs) were calculated using URMEL-T with the resistance-band model. In addition, the concept of the structure parameters of the niobium cavity introduced the condition of calculation reliability with the codes; the calculation reliabilities of URMEL and URMEL-T were also discussed.