X-ray optics for advanced ultrafast pump-probe X-ray experiments at SACLA.

Tetsuo Katayama,Taito Osaka,Yuki Morioka,Yasuhisa Sano,Takashi Hirano,Shigeki Owada,Tadashi Togashi,Makina Yabashi

doi:10.1107/s1600577518018362

Abstract

X-ray optics were implemented for advanced ultrafast X-ray experiments with different techniques at the hard X-ray beamline BL3 of SPring-8 Ångstrom Compact free-electron LAser. A double channel-cut crystal monochromator (DCCM) and compound refractive lenses (CRLs) were installed to tailor the beam conditions. These X-ray optics can work simultaneously with an arrival-timing monitor that compensates for timing jitter and drift. Inner-walls of channel-cut crystals (CCs) in the DCCM were processed by plasma chemical vaporization machining to remove crystallographic damage. Four-bounced reflection profiles of the CCs were investigated and excellent diffraction qualities were achieved. The use of CRLs enabled two-dimensional X-ray focusing with a spot size of ∼1.5 µm × 1.5 µm full width at half-maximum, while keeping reasonable throughputs for a wide photon energy range of 5-15 keV.

Highlights

At SPring-8 Angstom Compact free-electron LAser (SACLA; Ishikawa et al, 2012), constructed in Harima, Japan, two hard X-ray beamlines (BL2 and BL3; Tono et al, 2013) and one soft X-ray beamline (BL1; Owada et al, 2018) are in operation for users, providing brilliant, ultrafast X-ray free-electron laser (XFEL) pulses
One of the advantages of using experimental hutch 2 (EH2) for pump–probe experiments is the proximity to an arrival-timing monitor (Katayama et al, 2016), which is located in experimental hutch 1 (EH1) of BL3
We describe a double channel-cut crystal monochromator (DCCM) and compound refractive lenses (CRLs; Lengeler et al, 1999; Snigirev et al, 1996), implemented for extending the XFEL scientific capabilities at BL3 of SACLA

Summary

Introduction

At SPring-8 Angstom Compact free-electron LAser (SACLA; Ishikawa et al, 2012), constructed in Harima, Japan, two hard X-ray beamlines (BL2 and BL3; Tono et al, 2013) and one soft X-ray beamline (BL1; Owada et al, 2018) are in operation for users, providing brilliant, ultrafast X-ray free-electron laser (XFEL) pulses. We describe a double channel-cut crystal monochromator (DCCM) and compound refractive lenses (CRLs; Lengeler et al, 1999; Snigirev et al, 1996), implemented for extending the XFEL scientific capabilities at BL3 of SACLA. These X-ray optical devices were carefully designed to avoid interference with the À1st-order branch for the arrival-timing diagnostics. We report the results of the performance test using the XFEL beam

Double channel-cut crystal monochromator

Compound refractive lenses

Spatial profile and throughput of the DCCM

Focusing property of CRLs

Application

Conclusions