9-cell超导腔快速预调谐方法研究

朱航; 翟纪元; 戴建枰

doi:10.11884/HPLPB202234.220061

9-cell超导腔快速预调谐方法研究

doi: 10.11884/HPLPB202234.220061

朱航^{1, 2,},
翟纪元^{1, 2, ,},
戴建枰¹

1.
中国科学院高能物理研究所加速器中心，北京 100049
2.
中国科学院大学，北京 100049

详细信息

作者简介:
朱　航，zhuhang@ihep.ac.cn

通讯作者:
翟纪元，zhaijy@ihep.ac.cn

中图分类号: TL503.2
计量
- 文章访问数: 629
- HTML全文浏览量: 238
- PDF下载量: 89
- 被引次数: 0
出版历程
- 收稿日期: 2022-03-05
- 修回日期: 2022-06-13
- 网络出版日期: 2022-06-16
- 刊出日期: 2022-08-22

Research on fast pre-tuning method of 9-cell superconducting cavities

Zhu Hang^{1, 2
,},
Zhai Jiyuan^{1, 2
, ,},
Dai Jianping¹

1.
Accelerator Research Center, Institute of High Energy Physics, Chinese Academy of Sciences, Beijing 100049, China
2.
University of Chinese Academy of Sciences, Beijing 100049, China

摘要

摘要: 对频率和场平坦度的预调谐是9-cell超导腔耗时最多的后处理工序之一，很快将成为国内相关大科学工程9-cell腔批量生产的瓶颈。首先介绍了9-cell超导腔两种常用的预调谐方法，即DESY方法和Cornell方法的原理，建模分析和比较了两种方法的计算精度和误差来源，给出Cornell方法调谐量计算的修正。然后结合9-cell超导腔预调谐实验研究，给出了快速预调谐方法：DESY的重建算法在低场平时精度较高且收敛迅速，可作为粗调；Cornell微扰算法在高场平时精度较高且测量迅速，可作为微调。结合两种调谐方式，将预调谐分为粗调和微调两步，可有效提升9-cell超导腔预调谐的速度。
- 9-cell超导腔 /
- 预调谐 /
- 场平坦度 /
- 拉珠测量
Abstract: The pre-tuning of frequency and field flatness is one of the most time-consuming post-processing procedures for 9-cell superconducting cavities, and will soon become the bottleneck of mass production of 9-cell cavities in domestic related major scientific projects. In this paper we firstly introduce two commonly used pre-tuning methods for 9-cell superconducting cavities, namely DESY method and Cornell method. Then we analyze and compare their calculation accuracy and error sources by modeling, and make a correction on the Cornell method’s tuning amount calculation. Verifing the pre-tuning of several cavities by the experimental research, we give a fast pre-tuning method in which DESY reconstruction algorithm is used for coarse-tuning as it has high precision and rapid tuning speed in low field flatness and Cornell perturbation algorithm is used for fine-tuning as it has high precision in high field flatness with faster measurement. Combining these two tuning algorithms, the pre-tuning is divided into two steps: coarse tuning and fine tuning, which can effectively improve the pre-tuning speed of the 9-cell superconducting cavity.
- 9-cell superconducting cavity /
- pre-tuning /
- field flatness /
- bead pull measurement

HTML全文

图 1 多cell超导腔电路模型

Figure 1. Circuit model of multi-cell cavity

下载: 全尺寸图片幻灯片

图 2 9-cell腔N005调谐前后场分布对比

Figure 2. 9-cell cavity N005 field flatness tuning

下载: 全尺寸图片幻灯片

表 1 DESY与Cornell预调谐方法微扰量计算结果对比

Table 1. Comparison of perturbation calculation results between DESY and Cornell pre-tuning method

cell number	perturbation amount $ {e}_{\mathrm{r}\mathrm{e}\mathrm{f}}/{10}^{-4} $	perturbation amount $ {e}_{\mathrm{D}\mathrm{E}\mathrm{S}\mathrm{Y}}/{10}^{-4} $	perturbation amount $ {e}_{\mathrm{C}\mathrm{o}\mathrm{r}\mathrm{n}\mathrm{e}\mathrm{l}\mathrm{l}}/{10}^{-4} $
1	5	4.96	6.21
2	4	3.93	4.18
3	−4	−4.03	−4.84
4	2	2.02	1.90
5	−3	−2.99	−2.70
6	2	2.03	1.97
7	−1	−0.99	−1.35
8	−4	−3.99	3.50
9	6	6.02	5.92

下载: 导出CSV

表 2 DESY与Cornell预调谐方法微扰量计算结果百分比误差对比

Table 2. Comparison of perturbation percentage error of DESY and Cornell pre-tuning method

cell number	percentage error $ {E}_{\mathrm{D}\mathrm{E}\mathrm{S}\mathrm{Y}} $/%	percentage error $ {E}_{\mathrm{C}\mathrm{o}\mathrm{r}\mathrm{n}\mathrm{e}\mathrm{l}\mathrm{l}} $/%
1	−0.84	24.14
2	−1.87	4.61
3	0.71	20.96
4	0.94	−4.94
5	−0.47	−9.98
6	1.41	−1.42
7	−1.46	35.15
8	−0.03	−12.49
9	0.25	−1.26

下载: 导出CSV

表 3 DESY和Cornell方法计算微扰量的均方根误差随场分布变化趋势

Table 3. Perturbation RMS error of DESY and Cornell method with different field flatness

field flatness/%	RMSE $ {\eta }_{\mathrm{d}\mathrm{e}\mathrm{s}\mathrm{y}}/{10}^{-4} $	RMSE $ {\eta }_{\mathrm{C}\mathrm{o}\mathrm{r}\mathrm{n}\mathrm{e}\mathrm{l}\mathrm{l}}/{10}^{-4} $
60	0.055	2.11
70	0.076	2.74
80	0.033	0.96
90	0.015	0.45

下载: 导出CSV

表 4 场平调节至95%时不同方法调谐时间对比

Table 4. Pre-tuning time of different methods for 95% field flatness (FF)

method	number of cells tuned	measure time/h	tuning time/h	total time/h
Cornell only	22 (FF ＞ 95%)	0.2	6.6	6.8
DESY only	9 (FF ＜ 90%)	0.6	2.7	3.3
combined method	13 (FF ＞ 95%)	0.9	3.9	4.8

下载: 导出CSV

参考文献(16)

[1]	The CEPC Study Group. CEPC conceptual design report: volume 1—accelerator[R]. IHEP-AC-2018-01, 2018: 88-94.
[2]	Bambade P, Barklow T, Behnke T, et al. The international linear collider: a global project[R]. DESY 19-037, 2019: 8-12.
[3]	Singer W, Brinkmann A, Brinkmann R, et al. Production of superconducting 1.3-GHz cavities for the European X-ray Free Electron Laser[J]. Physical Review Accelerators and Beams, 2016, 19: 092001. doi: 10.1103/PhysRevAccelBeams.19.092001
[4]	Marhauser F, Daly E F, Fitzpatrick J A, et al. Status of the LCLS-II accelerating cavity production[C]//Proceedings of IPAC 2017. 2017: 1164-1166.
[5]	Huang Nanshun, Deng Haixiao, Liu Bo, et al. Features and futures of X-ray free-electron lasers[J]. The Innovation, 2021, 2: 100097.
[6]	李波, 刘华昌, 王云, 等. CSNS-II超导椭球腔形变电场平坦度仿真分析[J]. 强激光与粒子束, 2021, 33:034001 doi: 10.11884/HPLPB202133.200259 Li Bo, Liu Huachang, Wang Yun, et al. Simulating analysis on electric field flatness of deformed superconducting elliptical cavity for CSNS-II linac[J]. High Power Laser and Particle Beams, 2021, 33: 034001 doi: 10.11884/HPLPB202133.200259
[7]	Shishido T, Kako E, Noguchi S, et al. Frequency tuning of an accelerating mode in STF baseline SC cavities[C]//Proceedings of the 3rd Annual Meeting of Particle Accelerator Society of Japan and the 31th Linear Accelerator Meeting in Japan. 2006: 865-867.
[8]	Shishido T, Kako E, Noguchi S. Development of pre-tuning system for 972 MHz 9-cell superconducting cavities[C]//Proceedings of the 11th Workshop on RF Superconductivity. 2003: 425-428.
[9]	Tajima T, Furuya T, Suzuki T, et al. Pre-tuning of TRISTAN superconducting RF cavities[C]//Proceedings of the Fourth Workshop on RF Superconductivity. 1989: 821-847.
[10]	Sekutowicz J, Chen Yinghua, Wei Yixiang. A different tuning method for accelerating cavities[C]//Proceedings of the Fourth Workshop on RF Superconductivity. 1989: 849-857.
[11]	Padamsee H, Knobloch J, Hays T. RF superconductivity for accelerators[M]. New York: Wiley, 1998: 129-143.
[12]	Liu Yang, He Feisi, Xu Wencan, et al. Tuning for the first 9-cell TESLA cavity of PKU[J]. Chinese Physics C, 2010, 34(4): 496-498. doi: 10.1088/1674-1137/34/4/015
[13]	郭志达, 李中泉, 翟纪元, 等. 1.3 GHz 9单元Ichiro型模型铜腔的预调谐[J]. 强激光与粒子束, 2011, 23(1):175-178 doi: 10.3788/HPLPB20112301.0175 Guo Zhida, Li Zhongquan, Zhai Jiyuan, et al. Pretuning of 1.3 GHz 9-cell Ichiro copper cavity[J]. High Power Laser and Particle Beams, 2011, 23(1): 175-178 doi: 10.3788/HPLPB20112301.0175
[14]	Tang Zhengbo, Ma Zhenyu, Hou Hongtao, et al. Frequency control and pre-tuning of a large aperture 500 MHz 5-cell superconducting RF cavity[J]. Nuclear Science and Techniques, 2014, 25: 030102.
[15]	Arnold A, Buettig H, Janssen D, et al. Field reconstruction by passband frequency measurement at the Rossendorf SRF-gun cavity[C]//Proceedings of SRF 2007. 2007: 689-691.
[16]	Slater J C. Microwave electronics[J]. Reviews of Modern Physics, 1946, 18(4): 441-512. doi: 10.1103/RevModPhys.18.441