Development and Vertical Tests of CEPC 650-MHz Single-Cell Cavities with High Gradient
A circular electron positron collider (CEPC) will adopt hundreds of 650-MHz superconducting cavities with high quality factor (<i>Q</i>) and accelerating gradient (<i>E</i><sub>acc</sub>). Two 650-MHz single-cell cavities made of fine-grain niobium were first trea...
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2021-12-01
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| Online Access: | https://www.mdpi.com/1996-1944/14/24/7654 |
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| author | Song Jin Peng Sha Weimin Pan Jiyuan Zhai Zhenghui Mi Feisi He Chao Dong Lingxi Ye Xiangcong He |
| author_facet | Song Jin Peng Sha Weimin Pan Jiyuan Zhai Zhenghui Mi Feisi He Chao Dong Lingxi Ye Xiangcong He |
| author_sort | Song Jin |
| collection | DOAJ |
| description | A circular electron positron collider (CEPC) will adopt hundreds of 650-MHz superconducting cavities with high quality factor (<i>Q</i>) and accelerating gradient (<i>E</i><sub>acc</sub>). Two 650-MHz single-cell cavities made of fine-grain niobium were first treated via buffered chemical polishing (BCP), which was easy and convenient. However, the vertical test results could not meet the specification of the CEPC (4 × 10<sup>10</sup> at 22 MV/m). Therefore, electro-polishing (EP) of 650-MHz single-cell cavities was conducted, which was complicated but remarkably effective. Both 650-MHz single-cell cavities achieved state-of-the-art gradients of 35 MV/m after the EP process, which is extremely high for large elliptical cavities (frequency < 1 GHz). One cavity achieved an intrinsic quality factor (<i>Q</i><sub>0</sub>) of 4.5 × 10<sup>10</sup> at 22.0 MV/m, which was higher than the CEPC spec. The other cavity obtained a lower <i>Q</i><sub>0</sub> of 3.4 × 10<sup>10</sup> at 22.0 MV/m, which may have resulted from the cancellation of high-temperature annealing. |
| first_indexed | 2024-03-10T03:39:48Z |
| format | Article |
| id | doaj.art-27cb2952353d4c8e851179ade3eda997 |
| institution | Directory Open Access Journal |
| issn | 1996-1944 |
| language | English |
| last_indexed | 2024-03-10T03:39:48Z |
| publishDate | 2021-12-01 |
| publisher | MDPI AG |
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| series | Materials |
| spelling | doaj.art-27cb2952353d4c8e851179ade3eda9972023-11-23T09:21:04ZengMDPI AGMaterials1996-19442021-12-011424765410.3390/ma14247654Development and Vertical Tests of CEPC 650-MHz Single-Cell Cavities with High GradientSong Jin0Peng Sha1Weimin Pan2Jiyuan Zhai3Zhenghui Mi4Feisi He5Chao Dong6Lingxi Ye7Xiangcong He8Accelerator Division, Institute of High Energy Physics, Chinese Academy of Sciences, Beijing 100049, ChinaAccelerator Division, Institute of High Energy Physics, Chinese Academy of Sciences, Beijing 100049, ChinaAccelerator Division, Institute of High Energy Physics, Chinese Academy of Sciences, Beijing 100049, ChinaAccelerator Division, Institute of High Energy Physics, Chinese Academy of Sciences, Beijing 100049, ChinaAccelerator Division, Institute of High Energy Physics, Chinese Academy of Sciences, Beijing 100049, ChinaAccelerator Division, Institute of High Energy Physics, Chinese Academy of Sciences, Beijing 100049, ChinaAccelerator Division, Institute of High Energy Physics, Chinese Academy of Sciences, Beijing 100049, ChinaAccelerator Division, Institute of High Energy Physics, Chinese Academy of Sciences, Beijing 100049, ChinaAccelerator Division, Institute of High Energy Physics, Chinese Academy of Sciences, Beijing 100049, ChinaA circular electron positron collider (CEPC) will adopt hundreds of 650-MHz superconducting cavities with high quality factor (<i>Q</i>) and accelerating gradient (<i>E</i><sub>acc</sub>). Two 650-MHz single-cell cavities made of fine-grain niobium were first treated via buffered chemical polishing (BCP), which was easy and convenient. However, the vertical test results could not meet the specification of the CEPC (4 × 10<sup>10</sup> at 22 MV/m). Therefore, electro-polishing (EP) of 650-MHz single-cell cavities was conducted, which was complicated but remarkably effective. Both 650-MHz single-cell cavities achieved state-of-the-art gradients of 35 MV/m after the EP process, which is extremely high for large elliptical cavities (frequency < 1 GHz). One cavity achieved an intrinsic quality factor (<i>Q</i><sub>0</sub>) of 4.5 × 10<sup>10</sup> at 22.0 MV/m, which was higher than the CEPC spec. The other cavity obtained a lower <i>Q</i><sub>0</sub> of 3.4 × 10<sup>10</sup> at 22.0 MV/m, which may have resulted from the cancellation of high-temperature annealing.https://www.mdpi.com/1996-1944/14/24/7654SRF cavityelectro-polishingquality factoraccelerating gradientvertical testbuffered chemical polishing |
| spellingShingle | Song Jin Peng Sha Weimin Pan Jiyuan Zhai Zhenghui Mi Feisi He Chao Dong Lingxi Ye Xiangcong He Development and Vertical Tests of CEPC 650-MHz Single-Cell Cavities with High Gradient Materials SRF cavity electro-polishing quality factor accelerating gradient vertical test buffered chemical polishing |
| title | Development and Vertical Tests of CEPC 650-MHz Single-Cell Cavities with High Gradient |
| title_full | Development and Vertical Tests of CEPC 650-MHz Single-Cell Cavities with High Gradient |
| title_fullStr | Development and Vertical Tests of CEPC 650-MHz Single-Cell Cavities with High Gradient |
| title_full_unstemmed | Development and Vertical Tests of CEPC 650-MHz Single-Cell Cavities with High Gradient |
| title_short | Development and Vertical Tests of CEPC 650-MHz Single-Cell Cavities with High Gradient |
| title_sort | development and vertical tests of cepc 650 mhz single cell cavities with high gradient |
| topic | SRF cavity electro-polishing quality factor accelerating gradient vertical test buffered chemical polishing |
| url | https://www.mdpi.com/1996-1944/14/24/7654 |
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