Decker Franz-Josef, Bane Karl L, Colocho William, Gilevich Sasha, Marinelli Agostino, Sheppard John C, Turner James L, Turner Joshua J, Vetter Sharon L, Halavanau Aliaksei, Pellegrini Claudio, Lutman Alberto A
SLAC National Accelerator Laboratory, 2575 Sand Hill Road, Menlo Park, CA, 94025, USA.
Sci Rep. 2022 Feb 28;12(1):3253. doi: 10.1038/s41598-022-06754-y.
X-ray Free Electron Lasers provide femtosecond x-ray pulses with narrow bandwidth and unprecedented peak brightness. Special modes of operation have been developed to deliver double pulses for x-ray pump, x-ray probe experiments. However, the longest delay between the two pulses achieved with existing single bucket methods is less than 1 picosecond, thus preventing the exploration of longer time-scale dynamics. We present a novel two-bucket scheme covering delays from 350 picoseconds to hundreds of nanoseconds in discrete steps of 350 picoseconds. Performance for each pulse can be similar to the one in a single pulse operation. The method has been experimentally tested with the Linac Coherent Light Source (LCLS-I) and the copper linac with LCLS-II hard x-ray undulators.
X射线自由电子激光可提供具有窄带宽和前所未有的峰值亮度的飞秒X射线脉冲。已开发出特殊的运行模式来产生双脉冲，用于X射线泵浦、X射线探测实验。然而，现有的单桶方法实现的两个脉冲之间的最长延迟小于1皮秒，因此阻碍了对更长时间尺度动力学的探索。我们提出了一种新颖的双桶方案，以350皮秒的离散步长覆盖从350皮秒到数百纳秒的延迟。每个脉冲的性能可以与单脉冲运行中的性能相似。该方法已在直线加速器相干光源（LCLS-I）和配备LCLS-II硬X射线波荡器的铜直线加速器上进行了实验测试。
