The commissioning results of the first undulator beamline at the Pohang Light Source

The initial commissioning results obtained from the first undulator beamline at the Pohang Light Source are reported. The beamline was designed to cover a photon energy range of 50-1500 eV with high spectral resolution and high photon flux (H.J. Shin, J. Korean Phys. Soc. 34 (1999) 350). It is equipped with a variable-included angle plane-grating monochromator. The measured spectra of the inner shell excitations in inert Ar and Ne gases and molecular N ₂ show that the spectral resolving power is about 6500 below 600 eV and larger than 4000 at higher photon energy ranges. The photon flux measured with an Si photodiode is of the order of 10 ¹¹-10 ¹² (photons/s/0.1% BW/200 mA).