Transverse gradient in Apple-type undulators.
Transverse gradient in Apple-type undulators.
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DOI：
10.1107/s1600577517004726
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发表时间：
2017-05-01
影响因子：
2.5
通讯作者：
Schmidt T
中科院分区：
文献类型：
--
作者：
Calvi M;Camenzuli C;Prat E;Schmidt T
这个理论证明了在Apple型波荡器中存在一个可变的横向K梯度。数值模拟的支持，以评估这种分析方法的局限性。苹果型波荡器是全球公认的最灵活的设备，用于生产可变偏振光的软X射线制度，无论是在同步加速器和自由电子激光设施。最近，横向梯度波荡器的实现已经被提出来增强新一代光源的性能。本文证明了苹果波荡器不仅能产生线偏振光和椭圆偏振光，而且在一定条件下还能产生可变的横向梯度。本文介绍了一个计算Apple波荡器K值及其横向梯度的一般理论框架，计算了所有常规工作模式和不同Apple类型（包括最近的Delta型和Apple X）的K值及其横向梯度的公式，并进行了严格的讨论。
This theory demonstrates the existence of a variable transverse K gradient in Apple-type undulators. It is supported by numerical simulations to assess the limits of this analytical approach. Apple-type undulators are globally recognized as the most flexible devices for the production of variable polarized light in the soft X-ray regime, both at synchrotron and free-electron laser facilities. Recently, the implementation of transverse gradient undulators has been proposed to enhance the performance of new generation light sources. In this paper it is demonstrated that Apple undulators do not only generate linear and elliptical polarized light but also variable transverse gradient under certain conditions. A general theoretical framework is introduced to evaluate the K-value and its transverse gradient for an Apple undulator, and formulas for all regular operational modes and different Apple types (including the most recent Delta type and Apple X) are calculated and critically discussed.