Air-cooled Magnetic Alloy Cavity for J-PARC Doubled Rep.-rate Scenario
Air-cooled Magnetic Alloy Cavity for J-PARC Doubled Rep.-rate Scenario
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DOI：
10.18429/jacow-ipac2014-thpri046
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发表时间：
2014-07
期刊：
影响因子：
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通讯作者：
C. Ohmori;K. Hara;K. Hasegawa;M. Nomura;A. Schnase;T. Shimada;K. Takata;F. Tamura;M. Toda;Masanobu Yamamoto;M. Yoshii
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文献类型：
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作者：
C. Ohmori;K. Hara;K. Hasegawa;M. Nomura;A. Schnase;T. Shimada;K. Takata;F. Tamura;M. Toda;Masanobu Yamamoto;M. Yoshii
基于双重频场景的J-PARCMR（主环）升级项目正在进行中，可提供750千瓦的波束功率。目前的射频部分将采用9组新型磁性合金FT3L，腔体采用直接水冷方案。直接水冷是冷却磁合金磁芯的有效方案，尽管它需要专用的高质量冷却水，且不含氧化铜和铜离子，因为铜离子可能对磁合金磁芯造成严重的腐蚀损坏。这些空腔将用于需要高负荷运行的基本射频加速。二次谐波 RF 对于增加束长度是必要的。这允许放大束流，因为它减轻了注入期间的空间电荷效应。由于二次谐波 RF 的高阻抗 FT3L 和低占空比操作，二次谐波 RF 系统中的功率损耗变得适中。风冷腔体设计适合安装在 MR 中无法获得专用优质水的任何位置。本文报告了第二个射频系统的设计、生产适合空气冷却的磁性合金磁芯的技术问题以及系统的构造。
TheupgradeprojectoftheJ-PARCMR(MainRing)based on doubled repetition-rate scenario is in progress to deliver the beam power of 750 kW. The present RF section will be occupied by 9 sets of new magnetic alloy, FT3L, cavities using the direct water cooling scheme. The direct water coolingistheefficientschemetocoolthemagneticalloycore although it requires dedicated high-quality cooling water whichdoesnotcontaincopperoxideandcopperionsbecause copper ions may cause the severe corrosion damage on the magnetic alloy cores. These cavities will be used for the fundamental RF for acceleration which requires high duty operation. The second harmonic RF is necessary to increase the bunch length. This allows to enlarge the beam current because it relaxes the space charge effects during the injection. Thanks to the high impedance FT3L and low duty operation of the second harmonic RF, the power loss in the second harmonic RF system becomes moderate. The air cooled cavity is designed to fit in any locations in the MR where the dedicated high-quality water is not available. This paper reports the design of the second RF system, technical issues to produce the magnetic alloy cores to fit the air cooling, and construction of the system.