Design of nano-ARPES beamline at 3-GeV next-generation synchrotron radiation facility, NanoTerasu

The beamline for angle-resolved photoemission spectroscopy (ARPES) with a nano-focused beam (nano-ARPES) is planned as one of the public beamlines in NanoTerasu, the 3-GeV next-generation synchrotron radiation facility at Tohoku, Japan, which is scheduled to start operation in 2024. A 4 m long APPLE-II type undulator provides brilliant soft X-rays with various polarizations (linear horizontal and vertical, and left and right circular) in the energy range of 50-1,000 eV. A collimated plane grating monochromator is adopted as a soft X-ray monochromator because we can select the demagnification factor of grating cf f = cosα/cosβ between the high energy-resolution (HR) mode for HR-ARPES experiments and the low divergence mode for high-flux nano-ARPES measurements. This beamline aims to produce the high flux nano-focused beam by using ultrahigh precision reflective mirror optics, not a Fresnel zone plate used as a focusing optics in the previous nano-ARPES station at other synchrotron facilities.