Photon Factory


BL-28A/B : Variable Polarization VUV and Soft X-ray Spectroscopy


Beamline group  Subcommittee 1 (Photoelectron spectroscopy)
  • Angle-resolved photoelectron spectroscopy (ARPES)
  • Microspectroscopy
  • VUV spectroscopy
  • Photon energies between 30 and 300 eV are available.
  • Vertical and horizontal linear polarized and left and right circular polarized lights are available.
  • High-resolution ARPES measurements using micro-focused beams, at low temperatures down to 10 K, are possible at Branch A.
  • Branch B is a free port, at which a bring-your-own measurement equipment can be installed.
Area of research
  • Condensed matter physics
  • Surface physics
  • Kenichi Ozawa kenichi.ozawa(at)
  • Please change (at) to @ in the e-mail address.
  • The type of the sample holders used at the ARPES system at Branch A is an Omicron type, which is also employed at the PES system at BL-13B.


  • PF 2.5-GeV Ring, Elliptically-polarizing undulator with six variable rows of magnetic arrays
  • Variable-included-angle Monk-Gillieson-type monochromator with varied-line-spacing gratings (VLSGs)
  • Focusing mirror of Branch A: Kirkpatrick-Baez (K-B) mirror
  • Focusing mirror of Branch B: Toroidal mirror
Energy range
  • 30 – 300 eV
    Vertical and horizontal linear polarized lights
    Left and right circular polarized lights
  • E/ΔE > 20000 at 65 eV
Beam size
  • Branch A:12 (V) × 10 (H) µm at 200 eV
  • Branch B:40 (V) × 100 (H) µm at 100 eV
Photon flux
  • 1011 - 1012 photons/s
  • Branch A:Micro-ARPES system with an iGONIO manipulator (10 - 300 K)
  • Omicron-Scienta DA30 analyzer
Remote / Mail-in
  • Remote measurements are possible, but the sample transfer should be done manually.
Special notes


  1. K. Tsuchiya et al., AIP Conf. Proc., 1741, 020023 (2016), doi:10.1063/1.4952802 : [Elliptically-polarizing undulator with six variable rows of magnetic arrays]
  2. M. Kitamura et al., Rev. Sci. Instrum., 93, 033906 (2022), doi:10.1063/5.0074393 : [Micro-focusing of the beam by the K-B mirror]


KEK-PF Publication Database (Publications of BL-28A/B)

Last updated: 2023-01-31