Design of a prototype split-and-delay unit for XFEL pulses, and their evaluation by synchrotron radiation X-rays

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• 作者：Jun'ya Sakamoto ; Kenji Ohwada ; Masahiko Ishino ; Jun'ichiro Mizuki ; Masami Ando and Kazumichi Namikawa
• 关键词：split-and-delay unit ; Bragg case interferometer ; XFEL ; synchrotron radiation X-rays
• 刊名：Journal of Synchrotron Radiation
• 出版年：2017
• 出版时间：January 2017
• 年：2017
• 卷：24
• 期：1
• 页码：95-102
• 全文大小：1505K
• ISSN：1600-5775

文摘

A prototype split-and-delay unit (SDU) for X-ray free-electron laser (XFEL) pulses is proposed based on the Graeff–Bonse four-Bragg-reflection interferometer by installing 12.5° slopes. The SDU can continuously provide a delay time from approximately −20 to 40 ps with a resolution of less than 26 fs. Because the SDU was constructed from a monolithic silicon crystal, alignment is straightforward. The obtained thoroughputs of the SDU reached 0.7% at 7.46 keV and 0.02% at 14.92 keV. The tunability of the delay time using the proposed SDU was demonstrated by finding the interference effects of the split X-rays, and the time resolution of the proposed SDU was evaluated using the width of the interference pattern recorded on the X-ray charge-coupled device camera by changing the energy, i.e. longitudinal coherence length, of the incident X-rays. It is expected that the proposed SDU will be applicable to XFEL experiments using delay times from tens of femtoseconds to tens of picoseconds, e.g. intensity correlation measurements.