FlexPES beamline - Soft X-ray beamline for photoemission and X-ray absorption in solids and low density matter

MAX IV Laboratory

The FlexPES (Flexible PhotoElectron Spectroscopy) beamline is a user facility for a wide range of photoemission and soft X-ray absorption experiments in different sample environments and with different focusing conditions. Operation is expected to start in the middle of 2018. Up to four end stations can be accommodated on the two branches of the beamline simultaneously, providing users with a variety of techniques, different sample environments, detectors and sample handling facilities. One branch is reserved for UHV (ultra-high vacuum) experiments on solid samples; it is hosting a surface-science end station suitable for studies of surface reactions, adsorption, thin films, heterojunctions and nanostructures. Also, this branch has a free port for a second experiment, where any suitable equipment of external users can be connected and used. The other branch is dedicated to research on low-density matter. Here, one end station will be used for XPS and XAS experiments on gases, liquids and free clusters, and the development of a modular mobile gas phase end station for electron-ion coincidence experiments is currently underway.

The beamline is expected to come into commissioning phase in the spring 2018 and accept first visiting scientists after the summer 2018.

1. The UHV surface science end station is equipped with a hemispherical photoelectron analyzer (Scienta SES2002; to be upgraded), home-built partial electron yield MCP detector for XAS, energy-dispersive fluorescent yield detector for XAS (SiriusSD from RaySpec), one analysis chamber, two sample preparation chambers, one fast entry and storage chamber, facilities for sample transfer, manipulation, heating (up to 1200 C), cooling (down to 20 K), surface cleaning and characterization by low-energy electron diffraction.

2. The XPS/XAS station for low-density matter is equipped with a hemispherical photoelectron analyzer (Scienta R4000), one analysis, one preparation and one fast entry chamber, a collection of sample delivery systems (free cluster sources, molecular-beam sources, ovens, liquid jet source etc)
3. The mobile ICE (“Ions in Coincidence with Electrons”) setup will be equipped with a reaction microscope (from RoentDek, to be operated in COLTRIMS and VMI modes) with the time-of-flight detectors for ions and electrons, a magnetic-bottle spectrometer for electrons (self-built), and a sample delivery system. In addition, a chopper will be installed in the beamline to facilitate time synchronization with the synchrotron ring pulses.

Up to four scientists/engineers are expected to maintain and further develop the equipment and to support external user groups (once in regular operation)

The facility will provide (from mid 2018) services for visiting research groups in characterization of their samples with the following techniques:
High-resolution XPS and XAS, resonant photoemission (ResPES) and angle-resolved valence band spectroscopy (ARPES), electron-ion coincidence experiments

The beamline is headed by a beamline scientist, time for experiments is allocated through a peer review process by an external program advisory committee. The scientific scope of the beamline is defined in interaction with the management of MAX IV Laboratory and the Scientific Advisory Committee.