Design evolution and properties of superconducting parallel-bar rf-dipole deflecting and crabbing cavities
Design evolution and properties of superconducting parallel-bar rf-dipole deflecting and crabbing cavities
复制标题
超导平行杆射频偶极子偏转和偏转腔的设计演变和特性
DOI：
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发表时间：
2013
期刊：
影响因子：
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通讯作者：
J. Delayen
中科院分区：
文献类型：
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作者：
S. D. Silva;J. Delayen
偏转/斜移腔在不同的加速器应用中具有多种用途，主要用于将单个光束分离为多个光束以及在粒子对撞机中的相互作用点处旋转束团进行正面碰撞。偏转/斜移腔也用于束中的横向和纵向发射度交换、X射线脉冲压缩和束诊断。由于严格的尺寸限制和对具有低表面损耗的更高场梯度的要求，紧凑的超导偏转/斜移腔正在开发中。TEM类超导平行杆腔支持低工作频率，从而使设计有利于许多偏转/斜移腔应用。基于圆柱形直加载元件和矩形外导体的平行杆腔的设计已经发展，并通过修改设计几何形状来改进设计特性。改进后的设计与椭圆形加载元件和圆柱形外导体具有吸引人的属性，如低和良好平衡的峰值表面场和高的横向并联阻抗。另外，在高电流应用中，高阶模谱中的模的宽分离和低阶模的不存在是有利的。平行杆的几何形状演变成射频偶极子的几何形状，每个设计的性能进行了详细的分析。
Deflecting/crabbing cavities serve a variety of purposes in different accelerator applications, primarily in separating a single beam into multiple beams and in rotating bunches for head-on collisions at the interaction point in particle colliders. Deflecting/crabbing cavities are also used for transverse and longitudinal emittance exchange in beams, x-ray pulse compression, and for beam diagnostics. Compact superconducting deflecting/crabbing cavities are under development due to strict dimensional constraints and requirements for higher field gradients with low surface losses. The TEM-like superconducting parallel-bar cavity supports low operating frequencies, thus making the design favorable for many of the deflecting/crabbing cavity applications. The design of parallel-bar cavity based on cylindrical straight loading elements and rectangular outer conductors has evolved and been adapted to improve the design properties by modifying the design geometry. The improved design with trapezoidal-shaped loading elements and cylindrical outer conductor has attractive properties such as low and well-balanced peak surface fields and high transverse shunt impedance. Additionally the wide separation of modes in the higher order mode spectrum and the absence of lower-order mode are advantageous in high current applications. The evolution of the parallel-bar geometry into an rf-dipole geometry is presented with a detailed analysis of the properties for each design.