FlexPES: a versatile soft X‐ray beamline at MAX IV Laboratory

• Published in: Journal of synchrotron radiation 2023-07, Vol.30 (4), p.831-840
• Main Authors: Preobrajenski, Alexei, Generalov, Alexander, Öhrwall, Gunnar, Tchaplyguine, Maxim, Tarawneh, Hamed, Appelfeller, Stephan, Frampton, Eleanor, Walsh, Noelle
• Format: Article
• Language: English
• Subjects: Absorption spectroscopy; Accelerator Physics and Instrumentation; Acceleratorfysik och instrumentering; Beamlines; Electrons; Flavors; Fysik; High vacuum; Horizontal polarization; Ions; Laboratories; Materials science; multi-coincidence; Nanoparticles; Natural Sciences; Naturvetenskap; NEXAFS; Photoelectric emission; Photoelectron spectroscopy; Photoelectrons; Physical Sciences; Polarized radiation; Radiography; soft X-rays; Spectrum analysis; Surface chemistry; Synchrotrons; X-Rays
• ISSN: 1600-5775; 0909-0495; 1600-5775
• DOI: 10.1107/S1600577523003429

FlexPES is a soft X‐ray beamline on the 1.5 GeV storage ring at MAX IV Laboratory, Sweden, providing horizontally polarized radiation in the 40–1500 eV photon energy range and specializing in high‐resolution photoelectron spectroscopy, fast X‐ray absorption spectroscopy and electron–ion/ion–ion coincidence techniques. The beamline is split into two branches currently serving three endstations, with a possibility of adding a fourth station at a free port. The refocusing optics provides two focal points on each branch, and enables either focused or defocused beam on the sample. The endstation EA01 at branch A (Surface and Materials Science) is dedicated to surface‐ and materials‐science experiments on solid samples at ultra‐high vacuum. It is well suited not only to all flavours of photoelectron spectroscopy but also to fast (down to sub‐minute) high‐resolution X‐ray absorption measurements with various detectors. Branch B (Low‐Density Matter Science) has the possibility to study gas‐phase/liquid samples at elevated pressures. The first endstation of this branch, EB01, is a mobile setup for various ion–ion and electron–ion coincidence techniques. It houses a versatile reaction microscope, which can be used for experiments during single‐bunch or multi‐bunch delivery. The second endstation, EB02, is based on a rotatable chamber with an electron spectrometer for photoelectron spectroscopy studies on primarily volatile targets, and a number of peripheral setups for sample delivery, such as molecular/cluster beams, metal/semiconductor nanoparticle beams and liquid jets. This station can also be used for non‐UHV photoemission studies on solid samples. In this paper, the optical layout and the present performance of the beamline and all its endstations are reported. A new versatile beamline for experiments with soft X‐ray absorption, photoelectron emission and electron–ion coincidence spectroscopies is available at MAX IV Laboratory, Sweden, serving user communities from ultra‐high‐vacuum surface science to materials science and low‐density matter research.