|
Cavity-based x-ray free-electron lasers (CBXFEL) [1-6] will allow use of optical cavity feedback to support generation of fully coherent x-rays of high brilliance and stability by electrons in undulators.
CBXFEL optical cavities comprise Bragg-reflecting flat crystal mirrors, which ensure x-rays circulation on a closed orbit, and x-ray refractive lenses, which stabilize the orbit and refocus the x-rays back on the electrons in the undulator. Depending on the cavity design, there are tens of degrees of freedom of the optical elements, which can never be perfectly aligned.
Here, we study signatures of misalignment of the optical components and of the undulator source with the purposes of understanding the effects of misalignment on x-ray beam dynamics, understanding misalignment tolerances, and developing cavity alignment procedures. Betatron oscillations of the x-ray beam trajectory are one of the characteristic signatures of cavity misalignment. The studies are performed on an example of a four-crystal rectangular cavity (Fig. 1) using analytical and numerical wave optics as well as ray-tracing techniques [7]. Detailed results of the studies are published in [8].
References
[1] Z. Huang and R. D. Ruth, Phys. Rev. Lett. 96, 144801 (2006).
[2] K.-J. Kim, Yu. Shvyd’ko and S. Reiche, Phys. Rev. Lett. 100, 244802 (2008).
[3] K.-J. Kim and Yu. Shvyd’ko, Phys. Rev. ST Accel. Beams 12, 030703 (2009).
[4] G. Marcus et al., Proc. 38th Int. FEL Conf. 10.18429/JACoW-FEL2017-MOP061.
[5] H. P. Freund, P.J.M. van der Slot, Yu. Shvyd’ko, New J. Phys. 21, 093028 (2019).
[6] G. Marcus et al., Phys. Rev. Lett. 125, 254801 (2020).
[7] M. Sanchez del et al., J. Synchrotron Radiat. 18, 708 (2011).
[8] P. Qi and Yu. Shvyd’ko, Phys. Rev. Accel. Beams 25 (2022) 050701
Acknowledgements
Work at Argonne National Laboratory was supported by the U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences, under contract No. DE-AC02-06CH11357.
|
