Design and performance of an ultra-high-vacuum-compatible artificial channel-cut monochromator

Abstract

The design and performance of a novel ultra-high-vacuum-compatible artificial channel-cut monochromator that has been commissioned at undulator beamline 8-ID-I at the Advanced Photon Source are presented. Details of the mechanical and optical design, control system implementation and performance of the new device are given. The monochromator was designed to meet the challenging stability and optical requirements of the X-ray photon correlation spectroscopy program hosted at this beamline. In particular, the device incorporates a novel in-vacuum sine-bar drive mechanism for the combined pitch motion of the two crystals and a flexure-based high-stiffness weak-link mechanism for fine-tuning the pitch and roll of the second crystal relative to the first crystal. The monochromator delivers an exceptionally uniform and stable beam and thereby improved brilliance preservation.

The X-ray Correlation Spectroscopy instrument at the Linac Coherent Light Source

“…The DCM operates with Si(111) crystals and provides a monochromaticity of ÁE=E = 1.4 Â 10 À4 at 8 keV. If more monochromaticity is required, a Si(511) Channel-Cut Monochromator (CCM) (Narayanan et al, 2008) operating in the vertical scattering geometry provides an energy resolution of ÁE=E = 8.9 Â 10…”

The X-ray Pump–Probe instrument at the Linac Coherent Light Source

“…1). In that configuration a Si(111) channel-cut monochromator (CCM), operating in vertical scattering geometry (Narayanan et al, 2008), allows a narrower bandwidth (ÁE=E= 1:4 Â 10 À4 ) to be delivered to experiments that require broad and intensive scans of the incident photon energy.…”

Design of a cryo-cooled artificial channel-cut crystal monochromator for the European XFEL

“…Based on the water cooled, Ultra-High-Vacuum (UHV) compatible artificial channel-cut crystal monochromator design at the APS [1,2], and the replications used on XPP and XCS instruments at the LCLS [3,4] for different experiments, a cryogenically cooled one has been developed for the European XFEL X-ray beamlines, in collaboration with Argonne National Laboratory. In total six individual monochromators are needed at the moment and they will be equipped for FXE, HED and MID instruments.…”