Pohang Accelerator Laboratory

SSS (Soft X-ray Spectroscopy and Scattering) Beamline at PAL-XFEL covers soft X-ray energy range 250 – 1200 eV (1 – 5 nm wavelength) energy range. Utilizing this energy range which directly observes the transition from the outmost valence electrons in ligand elements (e.g. carbon, nitrogen, and oxygen), 3d transition metals (e.g. iron and copper), and rare-earth elements, the spectroscopy properties in materials can be clearly revealed by spectroscopic tools, as well as by scattering experiments. From the extremely short and bright X-ray pulses from PAL-XFEL, the researchers carry out time-resolved investigations on materials. There are three endstations in SSS beamline. XAS/XES Endstation operates from 2017 can perform time resolved X-ray emission and absorption spectroscopy experiments which provides complementary analysis of the conduction and valence bands of various materials. RSXS Endstation is open from 2020 to investigate the complex electronic ordering (charge/spin/orbital) using time-resolved resonant soft X-ray scattering experiments on quantum materials and strongly correlated systems. FTH/Forward scattering endstation open from 2021 for time resolved imaging experiment as well as X-ray absorption spectroscopy for various phase of sample systems.

Photon energy	250 — 1200 eV
Energy band width	~1 % (pink beam), 0.2 ~ 0.01 % (mono beam)
Pulse duration	~100 fs (FWHM) for monochromatic beam
X-ray polarization	Horizontal
Photons per pulse	~10¹² (pink), ~10⁹—10¹¹ (mono) at 800 eV
X-ray beam size	For RSXS, H: ~100 μm, V: <500 μm For XAS/XES, <50 μm x 50 μm (KB focused)
Optical laser	800 , 400 , 266 nm
Detectors	MCP (XAS) Andor NewtonDO(2D - XES) APD (0D - RSXS) PI-MTE (2D - FTH)

Photon energy

250 — 1200 eV

Energy band width

~1 % (pink beam), 0.2 ~ 0.01 % (mono beam)

Pulse duration

~100 fs (FWHM) for monochromatic beam

X-ray polarization

Horizontal

Photons per pulse

~10¹² (pink), ~10⁹—10¹¹ (mono) at 800 eV

X-ray beam size

For RSXS, H: ~100 μm, V: <500 μm
For XAS/XES, <50 μm x 50 μm (KB focused)

Optical laser

800 , 400 , 266 nm

Detectors

MCP (XAS)
Andor NewtonDO(2D - XES)
APD (0D - RSXS)
PI-MTE (2D - FTH)

Soft X-ray Instruments