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Cepc 650 MHz superconducting cavity acceleration gradient to a new high

On June 22 and July 12, shapeng and others from the Accelerator Center of the Institute of high energy of the Chinese Academy of Sciences conducted vertical tests (@ 2.0 K) at low temperature on two 650 MHz single cell superconducting cavities (1# cavity and 2# cavity) of the Ring Electron Positron Collider (cepc) on the advanced light source technology research and development and test platform (PAPS):the maximum acceleration gradient of the two superconducting cavities reached 41.0mv/m and 41.6mv/m respectively; Under the acceleration gradient of 40mv/m, the quality factor (q) of the two superconducting cavities reaches 1.7e10 and 2.5e10 respectively; In addition, in the test process, no field emission phenomenon occurred in the whole process of 1# cavity, and slight field emission occurred in the 2# cavity under the high acceleration gradient above 37mv/m. The test results show that the post-processing and testing processes of these two superconducting cavities are very successful.  

Due to its large volume and surface area and low frequency, the acceleration gradient of large-scale (frequency less than 1GHz) superconducting cavities in China has not exceeded 40mv/m, while there are only a few large-scale superconducting cavities exceeding 40mv/m in the world. Therefore, under the deployment of the RF superconducting and cryogenic research center of the Institute of high energy, the high frequency group of the Accelerator Center has carried out the research and development of cepc high-performance 650 MHz single cell superconducting cavity, hoping to achieve the long-term goal of cepc( [email protected] /m)。 The acceleration gradient of the two 650 MHz single cell superconducting cavities exceeds 40mv/m, which lays a foundation for the next step to continue to improve the Q value of the superconducting cavity.  

This research has been supported by the advanced light source R & D and testing platform, the national key R & D plan, the National Natural Science Foundation of China, Wang Yifang’s scientist studio and the innovation project of the Institute of high energy.  

Vertical test results of 650 MHz single cell superconducting cavity

(1 × cavity, 20220622; 2 × cavity, 20220712)