Applied Science and Convergence Technology 2022; 31(3): 71-74
Published online May 30, 2022
Copyright © The Korean Vacuum Society.
aPhysics Department, Chungbuk National University, Cheongju 28644, Republic of Korea
bPohang Accelerator Laboratory, Pohang 37673, Republic of Korea
This is an Open Access article distributed under the terms of the Creative Commons Attribution Non-Commercial License(http://creativecommons.org/licenses/by-nc/3.0) which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited.
A fourth-generation light source (Korea-4GLS) with 4-GeV electron energy, 58-pm-rad electron emittance, and 400-mA electron current is under construction at Ochang, Korea. Here, we describe the advantages of the Korea-4GLS compared with the light source at Pohang (Pohang Light Source: PLS-II) in terms of the geometry of its probing techniques and application materials. In the case of probing laterally homogeneous specimens where an X-ray size from 10 µm to 1 mm is permissible and the sample is generally larger, then techniques such as X-ray scattering, X-ray absorption spectroscopy, and X-ray photoelectron spectroscopy benefit from flux increase. In this case, the Korea-4GLS is better than the PLS-II in the energy range of approximately 1–2.5 keV (higher energy spectrum for soft X-ray-based techniques), 2–4 keV (medium energy-based techniques), and 10–100 keV (higher energy spectrum for hard X-ray-based techniques). When probing laterally inhomogeneous specimens, the X-ray size must be below 1 µm. Here, nano-probe and spectro-nanoscopy techniques, such as coherent diffraction imaging, ptychography, scanning type transmission X-ray microscopy, or photoelectron microscopy leverage the increase in brilliance. These techniques can leverage all photon energy ranges, especially soft X-ray spectro-nanoscopes (>100-fold gain at the focused area) that require an exit slit as a virtual light source.
Keywords: Fourth-generation light source, Korea-4GLS, Nanoprobe, Spectro-nanoscopy, Brilliance