Stabilization of high intensity beam by higher harmonic cavity in electron synchrotron

电子同步加速器高次谐波腔稳定高强度光束

• 批准号: 16560040
• 负责人: HINODE Fujio
• 金额: $ 2.3万
• 依托单位: Tohoku University
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (C)
• 财政年份: 2004
• 资助国家: 日本
• 起止时间: 2004 至 2006
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/en/grant/KAKENHI-PROJECT-16560040/
• 关键词: electron synchrotron; harmonic cavity; RF

A 1.2 GeV Stretcher-Booster (STB) ring at Laboratory of Nuclear Science(LNS), Tohoku University, has been mainly operated for experiments of nuclear physics. The STB is not the light source ring but also has storage ring-like function. One of the many issues limiting performance of the STB ring is supposed to be strong longitudinal coupled-bunch instability. Actually very strong synchrotron oscillation signal have been observed around 3.6 GHz with a threshold current of about 10 mA. In order to suppress the instability, applicability of a third-harmonic Landau cavity has been studied.For the full energy operation, analytic modeling and simulations were first performed. The results show that if three harmonic cavities are used, near-optimal bunch-lengthening may be obtained at the maximum ring current of 100 mA. For injection energy of 200 MeV, almost same analysis were performed and showed that increased energy spread from the instability or lost macro-particles occurred for nearly all currents and tuning angles. Although the simulation study indicates that more cavities are required to suppress the instability, one harmonic cavity was manufactured and tested in the STB as the first step of the study. The very strong synchrotron oscillation signal due to the coupled-bunch instability was drastically damped by the harmonic cavity at a specific tuning angle. However, it is not considered that this suppression is due to the usual Landau damping, since a significant voltage is never excited in the harmonic cavity because of the large tuning angle. A tracking simulation using rigid-bunch model was performed to understand this situation. The result showed that a higher order mode of harmonic cavity can suppress the instability. For the lower energy operation, the effect of harmonic cavity might be also interesting, but no obvious improvement has been seen yet. Toward the future development, a study of the harmonic cavity in acceleration process will be also progressed.

东北大学核科学实验室（LNS）的1.2 GeV拉伸助推器（STB）环主要用于核物理实验。机顶盒不是光源环，而是具有类似存储环的功能。限制 STB 环性能的众多问题之一被认为是强纵向耦合束不稳定性。实际上，在 3.6 GHz 附近观察到非常强的同步加速器振荡信号，阈值电流约为 10 mA。为了抑制不稳定性，研究了三次谐波朗道腔的适用性。对于全能量运行，首先进行了解析建模和仿真。结果表明，如果使用三个谐波腔，在最大环电流为 100 mA 时可以获得接近最佳的束延长。对于 200 MeV 的注入能量，进行了几乎相同的分析，结果表明几乎所有电流和调谐角度都会因不稳定性或丢失宏观粒子而导致能量扩散增加。尽管仿真研究表明需要更多的空腔来抑制不稳定性，但作为研究的第一步，在 STB 中制造并测试了一个谐波空腔。由于耦合束不稳定性而产生的非常强的同步加速器振荡信号在特定调谐角度被谐振腔极大地衰减。然而，不认为这种抑制是由于通常的朗道阻尼造成的，因为由于调谐角度大，谐波腔中永远不会激发显着的电压。使用刚性束模型进行跟踪模拟来了解这种情况。结果表明，谐波腔的高阶模态可以抑制不稳定性。对于较低能量的操作，谐波腔的效果可能也很有趣，但尚未看到明显的改进。未来的发展，加速过程中谐振腔的研究也将取得进展。

项目成果

Current status of a 1.2 GeV STB ring at Tohoku University

东北大学 1.2 GeV STB 环的现状

• 发表时间: 2004
• 期刊: 日本加速器学会 第1回年回 講演抄録集
• 作者: H. Hama;M. Kawai;F. Hinode;A. Kurihara;S. Takahashi;Y. Shibasaki;T. Tanaka;F.Hinode
• 通讯作者: F.Hinode

OPERATION STATUS OF LNS ACCELERATOR AND DEVELOPMENT

LNS加速器运行现状及发展

• 发表时间: 2006
• 期刊: Proceedings annual meeting of Particle Accelerator Society of Japan No.3, Sendai
• 作者: M. Kawai;F. Hinode;A. Kurihara;S. Takahashi;Y. Shibasaki;K. Nanbu;T. Mutou;T. Tanaka;K. Kasamsook;K. Akiyama;M. Yasuda;H. Hama
• 通讯作者: H. Hama

A Study on the Applicability of Landau Cavity to the 1.2 GeV Booster Synchrotron at Tohoku University

东北大学朗道腔在1.2 GeV助推同步加速器中的适用性研究

• 发表时间: 2007
• 期刊: Proceedings of APAC 2007
• 作者: K.Yamagata;Hiroshi Kezuka et al.;金子敏明;F.Hinode
• 通讯作者: F.Hinode

STATUS OF LNS ACCELERATOR COMPLEX AND A FUTURE PLAN OF COHERENT RADIATION FACILITY USING AN ISOCHRONOUS-BEND RING

LNS加速器复合体的现状和使用等时弯环的相干辐射设施的未来计划

• 发表时间: 2005
• 期刊: 日本加速器学会 第2回年回 講演抄録集
• 作者: M. Kawai;F. Hinode;A. Kurihara;S. Takahashi;Y. Shibasaki;K. Nanbu;T. Mutou;T. Tanaka;K. Kasamsook;K. Akiyama;M. Yasuda;H. Hama;H.Hama
• 通讯作者: H.Hama

A Study on the Applicability of Landau Cavity to the 1. 2 GeV Booster Synchrotron at Tohoku University

东北大学朗道腔在1. 2 GeV助推同步加速器中的适用性研究

• 发表时间: 2007
• 期刊: Proceedings of APAC 2007, Indore, India
• 作者: F. Hinode;K. Akiyama;H. Kama;M. Kawai;K. Kasamsook;A. Kurihara;T. Muto;K. Nanbu;Y. Shibasaki;S. Takahashi;T. Tanaka;M. Yasuda
• 通讯作者: M. Yasuda