AP‐XPS beamline, a platform for operando science at Pohang Accelerator Laboratory

• Published in: Journal of synchrotron radiation Vol. 27; no. 2; pp. 507 - 514
• Main Authors: Kim, Geonhwa, Yu, Youngseok, Lim, Hojoon, Jeong, Beomgyun, Lee, Jouhahn, Baik, Jaeyoon, Mun, Bongjin Simon, Kim, Ki-jeong
• Format: Journal Article
• Language: English
• Published: 5 Abbey Square, Chester, Cheshire CH1 2HU, England International Union of Crystallography 01.03.2020; John Wiley & Sons, Inc
• Subjects: AP‐XPS; beamline; Beamlines; Laboratories; PAL (PLS‐II); Photoelectric emission; Photoelectrons; Photon beams; Photons; Spectrum analysis; SPEM; PAL (PLS-II); beamline; SPEM; AP-XPS
• ISSN: 1600-5775; 0909-0495; 1600-5775
• DOI: 10.1107/S160057751901676X

Beamline 8A (BL 8A) is an undulator‐based soft X‐ray beamline at Pohang Accelerator Laboratory. This beamline is aimed at high‐resolution ambient‐pressure X‐ray photoelectron spectroscopy (AP‐XPS), soft X‐ray absorption spectroscopy (soft‐XAS) and scanning photoemission microscopy (SPEM) experiments. BL 8A has two branches, 8A1 SPEM and 8A2 AP‐XPS, that share a plane undulator, the first mirror (M1) and the monochromator. The photon beam is switched between the two branches by changing the refocusing mirrors after the monochromator. The acceptance angle of M1 is kept glancing at 1.2°, and Pt is coated onto the mirrors to achieve high reflectance, which ensures a wide photon energy range (100–2000 eV) with high resolution at a photon flux of ∼1013 photons s−1. In this article, the main properties and performance of the beamline are reported, together with selected experiments performed on the new beamline and experimental system. An ambient‐pressure photoemission spectroscopy beamline has been constructed and has recently begun regular user service at Pohang Accelerator Laboratory. This beamline is a soft X‐ray beamline with undulator (U6.8) insertion device and will be a platform for operando surface science.