Design and selection of 325MHz medium β Spoke cavity
-
摘要: 中国科学院高能物理研究所一直在研究频率为325 MHz、中低β Spoke超导加速腔,以应用在加速器驱动的次临界系统(ADS)的强流质子直线加速器中。通过对超导腔设计方法和设计原则的研究,使用CST仿真软件设计了单Spoke腔、双Spoke腔、三bar Spoke腔三种Spoke腔型。其中三bar Spoke腔和双Spoke腔一样,都有着三个加速间隙,但是Spoke柱的结构不同。在腔型设计中,对三种Spoke腔的模型均作了参数化处理。然后通过CST的参数化扫描来优化腔体形状以使得峰值电场与加速梯度的比值最小,同时使峰值磁场与加速梯度的比值处于较低范围。本文对三种腔型进行了高频结构优化和参数分析,选用了双Spoke腔型作为设计方案,并对电磁场等进行了优化设计。
-
关键词:
- 质子加速器 /
- 单Spoke腔 /
- 双Spoke腔 /
- 三bar Spoke腔 /
- 中β
Abstract: A 325 MHz Spoke cavity at medium and low β is developed in institute of High Energy Physics (IHEP) for the CiADS linac. Through the study on the principle of designing a superconducting cavity, three kinds of Spoke cavities including single Spoke cavity, double Spoke cavity and 3-bar Spoke cavity, were designed by the CST MWS.Although both the 3-bar Spoke and the double Spoke have a 3-gap structure, their Spoke bars are different. In the process of cavity design, parametric modeling was used to construct the cavity shape. Then the cavity shape was optimized by the parametric sweep in the CST MWS to minimize ratio of peak electric field to accelerating gradient (EP/Eacc) while keeping ratio of peak magnetic field to accelerating gradient (BP/Eacc) at a reasonably low range. Through the comparison of RF performance parameters, a double Spoke structure was selected as the design, and further optimization for electromagnetic field of double Spoke cavity is carried out.-
Key words:
- proton accelerator /
- single Spoke cavity /
- double Spoke cavity /
- 3-bar Spoke cavity /
- medium β
-
表 1 三种腔型高频参数对比
Table 1. Major RF performance parameters of three kinds of Spoke cavities
F/MHz EP/(MV/m) BP/mT Eacc/(MV/m) EP/Eacc (BP/Eacc)/[mT/(MV·m-1)] R/Q/Ω G/Ω TTFmax single Spoke cavity 325.11 5.40 12.54 1.56 3.46 8.03 258 113 0.82 double Spoke cavity 325.24 4.37 12.09 1.33 3.29 9.10 412 120 0.78 3-bar cavity 325.09 3.94 7.52 1.03 3.30 6.30 340 127 0.81 表 2 双Spoke腔的详细几何参数
Table 2. Main geometric parameters of the double Spoke cavity
(mm) Dcav Liris Lcav D D2 He H1 T1 W1 R1 T2 W2 R2 551 565 748 166 306 91.5 68 51 95 26 167 218 55 -
[1] Yan Fang, Li Zhihui, Meng Cai, et al. Physics design for the C-ADS main linac based on two different injector design schemes[J]. Chinese Physics C, 2014, 38(2): 82-90. [2] Delaine J R, Bohn C L. Heavy-ion superconducting linacs[C]//Proceedings of the Fourth Workshop on RF Superconductivity. 1989: 1451-1455. [3] Padamsee H, Knobloch J, Hays T. RF Superconductivity for accelerators[M]. Weinheim: Wiley-VCH, 2008: 179-197. [4] Shepard K W, Ostroumov P N, Delayen J R. High-energy ion linacs based on superconducting Spoke cavities[J]. Physical Review Special Topics—Accelerators and Beams, 2003, 6: 080101. doi: 10.1103/PhysRevSTAB.6.080101 [5] Hopper C S, Delayen J R. Superconducting Spoke cavities for high-velocity applications[J]. Physical Review Special Topics—Accelerators and Beams, 2013, 16: 102001. doi: 10.1103/PhysRevSTAB.16.102001 [6] He F S, Rimmer R A, Wang H. A new cavity design for medium beta acceleration[C]//16th International Conference on RF Superconductivity. 2013: 23-27. [7] Ristori L, Apollinari G, Borissov E, et al. Design, fabrication and testing of single Spoke resonators at fermilab[C]//Proceedings of the 14th International Conference on RF Superconductivity. 2009: 550-554. [8] Yao Zhongyuan, Lu Xiangyang, Zhao Kui. Design of a 450 MHz β=0.2 single Spoke cavity at PKU[J]. Chinese Physics C, 2009, 33(4): 292-296. doi: 10.1088/1674-1137/33/4/011 [9] 徐波, 张新颖, 李中泉, 等. 325 MHz低β半波长谐振腔设计[J]. 强激光与粒子束, 2013, 25(9): 2397-2402. doi: 10.3788/HPLPB20132509.2397Xu Bo, Zhang Xinying, Li Zhongquan, et al. Design of 325 MHz low beta half wave resonator cavity. High Power Laser and Particle Beams, 2013, 25(9): 2397-2402 doi: 10.3788/HPLPB20132509.2397 [10] He F S, Zhao K. Some design analysis on the low-beta multi-spoke cavities[C]//Proceedings of the 15th International Conference on RF Superconductivity. 2011: 141-143.