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

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.

Source: Journal of Synchrotron Radiation - December 20, 2016 Category: Physics Authors: Sakamoto, J. Ohwada, K. Ishino, M. Mizuki, J. Ando, M. Namikawa, K. Tags: split-and-delay unit Bragg case interferometer XFEL synchrotron radiation X-rays research papers Source Type: research