The mechanical design, fabrication and tests of dressed 650 MHz 2-cell superconducting cavities for CEPC
The mechanical design, fabrication and tests of dressed 650 MHz 2-cell superconducting cavities for CEPC
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DOI：
10.1016/j.nima.2022.166590
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发表时间：
2022-03
期刊：
影响因子：
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通讯作者：
Xinying Zhang;P. Sha;W. Pan;J. Zhai;Zhongquan Li;C. Dong;Hongjuan Zheng;Z. Mi;Xiang-Cheng He;R. Ge;R. Han;Liang-rui Sun
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文献类型：
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作者：
Xinying Zhang;P. Sha;W. Pan;J. Zhai;Zhongquan Li;C. Dong;Hongjuan Zheng;Z. Mi;Xiang-Cheng He;R. Ge;R. Han;Liang-rui Sun
摘要环形正负电子对撞机（CEPC）的对撞环采用了650 MHz双室超导射频腔。通过优化壁厚和几何形状，修整腔的机械性能得到了显着改善，重点是应力，调谐能力，压力灵敏度和洛伦兹力失谐，同时仔细监测颤噪和屈曲。三个腔体随后被制造、后处理并接受垂直测试。在19.7MV/m时，腔体的最大无载品质因数（Q 0）达到3.2× 1010，超过了设计指标。同时也验证了小的洛仑兹力失谐系数的合理性。压力敏感性的测量和模拟预测一致。安装调谐器，基本和高阶模式（HOM）耦合器，两个修饰的650 MHz 2细胞腔最终集成到一个测试低温恒温器的光束测试设施。在2.0K下，两个腔都成功地调谐到650.000MHz的工作频率。本文介绍了650 MHz 2单元谐振腔的开发和低温测试中的机械方面。
Abstract 650 MHz 2-cell superconducting radio-frequency (SRF) cavities have been adopted for the collider ring of the Circular Electron Positron Collider (CEPC). By optimizing the wall thickness and geometry, the mechanical properties of the dressed cavity have been significantly improved with a focus on stress, tuning capabilities, pressure sensitivity, and Lorentz-force detuning, while microphonics and buckling were carefully monitored. Three cavities were later fabricated, post-processed and received vertical tests. The maximum unloaded quality factor (Q 0) of the cavities has reached 3.2× 10 10 at 19.7 MV/m, which exceeded the design goal during operation. The favored small coefficient of Lorentz-force detuning was validated, too. Pressure sensitivity was measured and consistent with simulation prediction. Mounted with tuners, fundamental and high-order-mode (HOM) couplers, two dressed 650 MHz 2-cell cavities were finally integrated into a test cryomodule for a beam test facility. Both cavities were successfully tuned to the operating frequency of 650.000 MHz at 2.0 K. This article covers the mechanical aspects in the development and cryogenic tests of the 650 MHz 2-cell cavities.