Matching unequal transverse emittances from an H- ion source into a RFQ
Matching unequal transverse emittances from an H- ion source into a RFQ
复制标题
DOI：
--
复制
发表时间：
1995
期刊：
影响因子：
--
通讯作者：
C. Planner
中科院分区：
文献类型：
--
作者：
C. Planner
已经提出并尝试了许多解决方案来匹配离子源的输出和RFQ1-15的输入。最流行的解决方案之一只使用两个螺线管。915螺线管可以很容易地调整，以提供进入RFQ的a和f3所需的匹配，但该解决方案假设发射率(相空间面积/RT)和两个横向相面中的输入束参数相等。磁控管和潘宁型的氢离子源的横向发射率可能有很大的不同，因此匹配到RFQ是更困难的，因为在RFQ的输入端，在两个相面中需要相同的ex和f3的值以及相同的束流大小。8它表明，通过使用两个以上的螺线管并控制耦合和聚焦，可以得到初始横向发射率不相等的匹配问题的解。耦合的控制导致RFQ的输入端的横向发射率相等，聚焦的控制，两个平面上的ex和f3的值相等。由于一阶耦合是线性的，所以四维超椭球体的超体积不变，系统在随后的线性变换后可以再次“解耦”。分析假定为空间电荷中和束，但讨论了S电荷的影响，并指出在线性空间电荷存在的情况下，匹配原理仍应适用。
A number of solutions have been proposed and tried for matching the output of an ion source to the input of a RFQ.1-15 One of the most popular solutions uses only tWo solenoids.915 The solenoids may be adjusted easily to provide the required match for a and f3 into the RFQ, but this solution assumes the emittances (phase space area/rt) and the input beam parameters in the two transverse phase planes are equal. HIon sources of the Magnetron and Penning type may have significantly different transverse emittances and matching into the RFQ is then more difficult since, at the input to the RFQ, tl,ie .,same values of ex and f3 are required in the two phase planes together with the same beam size.8 It is shown that by using more than two solenoids and controlling the coupling as well as the focusing it is possible to obtain a solution to the matching problem for unequal initial transverSe emittances. Control of the coupling results in equal transverse emittances at the input to the RFQ and control of the focusing, equal values for both ex and f3 in the two planes. Since to first order the coupling is linear there is no change to the hyper-volume of the four dimensional hyper-ellipsoid and the system could after subsequent linear transformation be 'uncoupled' again. The analysis assumes a space charge neutralised beam, but the effect of s]1ace charge is discussed and the principle for matching should still apply in the presence of linear space charge.