Pink-Beam Small-AngleX-ray Scattering Beamlineat the Extremely Brilliant High Energy Photon Source

The construction of the pink-beam small-angle X-ray scattering (SAXS) beamline, ID08, was completed at the High Energy Photon Source (HEPS) in 2025. To enable fast time-resolved scattering experiments, the ID08 beamline employs a pink X-ray beam as the fundamental photon source, which is emitted from an in-air planar undulator. The pink-beam exhibits an energy resolution of 0.95%, with a photon flux up to 3.2 × 1015 phs/s/0.1%bw@12 keV@200 mA and an energy coverage of 8–12 keV. The beam size at the sample position can be varied from 0.2 mm × 0.2 mm to 0.5 mm × 0.5 mm (H×V) using the primary slits. With the current beamline layout, the accessible q-range for SAXS measurement is 0.0105–6.68 nm–1, corresponding to a detectable particle size range of 1–600 nm. Coupled with three advanced pixel-array detectors and optical components installed at a later stage, such as compound refractive lens (CRL), this beamline enables not only millisecond-level time-resolved individual SAXS, wide-angle X-ray scattering (WAXS), and ultrasmall-angle X-ray scattering (USAXS) experiments but also simultaneous combined WAXS/SAXS/USAXS measurement. The HEPS-ID08 beamline supports both static and dynamic characterization of various material systems across length scales from angstrom down to submicron, opening up new avenues for structural investigations into non-equilibrium and time-dependent processes in materials.