Tetsuo Katayama 1,2 , Shigeki Owada 2 , Tadashi Togashi 1,2 , Kanade Ogawa 2 , Petri Karvinen 3 , Ismo Vartiainen 3 , Anni Eronen 3 , Christian David 3 , Takahiro Sato 2 , Kyo Nakajima 1,2 , Yasumasa Joti 1,2 , Hirokatsu Yumoto 1 , Haruhiko Ohashi 1 , Makina Yabashi 2
29 January 2016
We report a method for achieving advanced photon diagnostics of x-ray free-electron lasers (XFELs) under a quasi-noninvasive condition by using a beam-splitting scheme. Here, we used a transmission grating to generate multiple branches of x-ray beams. One of the two primary diffracted branches (+1st-order) is utilized for spectral measurement in a dispersive scheme, while the other (−1st-order) is dedicated for arrival timing diagnostics between the XFEL and the optical laser pulses. The transmitted x-ray beam (0th-order) is guided to an experimental station. To confirm the validity of this timing-monitoring scheme, we measured the correlation between the arrival timings of the −1st and 0th branches. The observed error was as small as 7.0 fs in root-mean-square. Our result showed the applicability of the beam branching scheme to advanced photon diagnostics, which will further enhance experimental capabilities of XFEL.