Design of a wide-energy-range nano-focus and high-resolution soft x-ray beamline

We present the optical design of a high-energy-resolution and nano spot size soft x-ray beamline for angle-resolved photoelectron spectroscopy measurements at the soon-to-be-constructed Wuhan Advanced Light Source. For the beamline part, two elliptical undulators provide photons covering the 10-1000 eV energy range with variable polarization. The expected energy resolution power of the beamline is ∼40 000 at 800 eV and a spot size of 500 × 500 nm2 (horizontal × vertical FWHM) at 200 eV with a flux of 1 × 1012 photons/s based on Kirkpatrick-Baez pairs.