Annual Report of Researches on High Current Superconducting Accelerating Technology for ERL-FEL

强流超导加速器是ERL的关键部件之一。该研究结合ERL对超导加速器的要求，对高性能射频超导腔的研制、强流高阶模耦合器研制、强流加速器恒温器设计研制、频率调谐器设计研制、麦克风效应和洛伦兹力失谐等问题进行深入研究。该年度主要进行强流超导腔的研制，包括冲压、成型、焊接、表面处理、场调平；进行强流超导腔的垂直性能测试；进行强流超导加速单元设计。研究组在强流超导腔研究中取得了进展，9-cell超导腔在32 MV/m时Q值在1E10以上，单cell超导腔在1.8 K，25 MV/m时，品质因数达到3E10以上，这对于强流超导加速器的运行有重要的意义。对超导腔场致发射点的定位进行了深入研究，为提高超导腔的性能提供了一种非常有效的方法。High current superconducting accelerator is one of the key components for ERL. Based on the requirement of superconducting accelerator for ERL, researches are carried out on fabrication of high performance superconducting cavities and high current HOM couplers, design and fabrication of cryomodule for high current accelerator, fabrication of frequency tuner, microphonics and Lorentz detuning, etc. In this year, the main work is focused on fabrication, treatment, vertical test of high current superconducting cavities and design of high current cryomodule. Progresses are obtained for high current superconducting cavities. The intrinsic quality factor of 9-cell cavity is larger than 1E10 at 32 MV/m. The intrinsic quality factor of single cell cavity reaches 3E10 at 25 MV/m at 1.8 K. The high quality factors are very helpful to the running of high current accelerators. Researches were carried out on the location of field emission of superconducting cavities, which provides an effective method to improve the performances of cavities.19181-1811