45A Submicron Soft X-ray Spectroscopy


Scientific Scope

  • Direct observation of charge and orbital orderings in magnetite
  • Determining the crystal-field ground states in rare earth heavy-fermion materials
  • Asymmetric orbital-lattice interactions in ultrathin correlated oxide films
  • Determining the quartet ground states using X-ray linear dichroism

Beamline Description

To facilitate ultra-high resolution spectroscopy measurements on sub-micron size single crystals, we have designed a Dragon-type soft-x-ray beamline that can achieve an energy resolving power greater than 50,000 for 400-1200 eV photon energies using a non-movable exit-slit scheme and a varied-line-space active grating of 1200/600 l/mm ruling density.  The resolving power is higher than 50,000 and the photon flux is greater than 1×1011 photons/sec for 700-800 eV photon energy ranges in which most photoelectron experiments will be carried out.  Two KB mirror sets, each containing a horizontal and a vertical mirror, are placed before and after the grating separately, to pre- and re-focus the undulator effective size of 240 μm in horizontal and 20 μm in vertical down to sub-microns scale at the sample position.  Among these KB mirrors, two horizontal ones are arranged in a two-stage demagnification scheme (0.192 × 0.019) and also avail to control the horizontal beam size with a slit at the first horizontal focal point.  With this slit wide open, the beam size at the sample position is 1.2 μm in horizontal and 0.4 μm in vertical, assuming a 1 μm opening for the grating monochromator exit slit. A sub-μm horizontal beam size can be obtained by closing down the horizontal opening of the slit at the first horizontal focal point.

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—Ashish Atma Chainani
Ext. 7247

BL Local Contact/Manager

Huang-Ming Tsai (蔡煌銘)
Ext. 7356


  • X-ray excited optical luminescence
  • Angular/spinresolved photoemission
  • X-ray emission
  • X-ray absorption
  • Magnetic circular dichroism


  • Topological insulators / metals / superconductors
  • Carbon-related systems and nanomaterials
  • Photovoltaic materials
  • Electron-correlated materials
  • Magnetic materials

General Information

  • Source: 45A
  • Energy Range: 280-1500 eV
  • Focused Spot Size: 1.2 × 0.4 μm² (H x V)
  • Status: under construction

National Synchrotron Radiation Research Center

101 Hsin-Ann Road, Hsinchu Science Park, Hsinchu, Taiwan 30076