Günther Benedikt, Dierolf Martin, Achterhold Klaus, Pfeiffer Franz
Department of Physics, Technical University of Munich, James-Franck-Straße 1, 85748 Garching, Germany.
J Synchrotron Radiat. 2019 Sep 1;26(Pt 5):1546-1553. doi: 10.1107/S1600577519006453. Epub 2019 Aug 7.
Compact X-ray sources based on inverse Compton scattering provide brilliant and partially coherent X-rays in a laboratory environment. The cross section for inverse Compton scattering is very small, requiring high-power laser systems as well as small laser and electron beam sizes at the interaction point to generate sufficient flux. Therefore, these systems are very sensitive to distortions which change the overlap between the two beams. In order to monitor X-ray source position, size and flux in parallel to experiments, the beam-position monitor proposed here comprises a small knife edge whose image is acquired with an X-ray camera specifically designed to intercept only a very small fraction of the X-ray beam. Based on the source position drift recorded with the monitor, a closed-loop feedback stabilizes the X-ray source position by adjusting the laser beam trajectory. A decrease of long-term source position drifts by more than one order of magnitude is demonstrated with this device. Consequently, such a closed-loop feedback system which enables stabilization of source position drifts and flux of inverse Compton sources in parallel to experiments has a significant impact on the performance of these sources.
基于逆康普顿散射的紧凑型X射线源可在实验室环境中产生高亮度且部分相干的X射线。逆康普顿散射的截面非常小，这需要高功率激光系统以及在相互作用点处较小的激光和电子束尺寸，以产生足够的通量。因此，这些系统对改变两束光重叠的畸变非常敏感。为了在进行实验的同时监测X射线源的位置、尺寸和通量，这里提出的束流位置监测器包括一个小的刀口，其图像由专门设计用于仅截取X射线束极小部分的X射线相机获取。基于监测器记录的源位置漂移，闭环反馈通过调整激光束轨迹来稳定X射线源的位置。使用该装置可证明长期源位置漂移减少了一个多数量级。因此，这样一个能够在进行实验的同时稳定逆康普顿源的位置漂移和通量的闭环反馈系统，对这些源的性能有重大影响。
