Introduction to the Endstation of the Hard X-ray Coherent Scattering Beamline at the High Energy Photon Source

Abstract

The hard X-ray coherent scattering (HXCS) beamline at the high energy photon source (HEPS) is designed for coherent diffractive imaging (CDI) and X-ray photon correlation spectroscopy (XPCS) using the high coherent flux of a diffraction-limited storage ring. This paper presents the design and implementation of the HXCS endstation. The endstation integrates nanofocusing optics, precision positioning systems, and photon-counting detector configurations to support ptychography, small-angle and wide-angle scattering XPCS. A dual sample-position scheme combines an advanced Kirkpatrick–Baez mirror system for nanofocusing and a compound refractive lens system for ptychography and XPCS. The mechanical design emphasizes stability and flexibility through interferometric position monitoring, granite-based structures, and reconfigurable subsystems. Commissioning results demonstrate a spatial resolution better than 10 nm for ptychography and an accessible timescale down to 20 μs for XPCS. The HXCS endstation provides a versatile platform for studies of structure and dynamics in materials, soft matter, and biological systems, with ongoing developments aimed at expanding sample environments and multimodal capabilities.