Beamline Description

Overview

The Materials Science Beamline was designed as a multipurpose beamline for surface science using photoemission spectroscopies, with a photon energy ranging from vacuum ultraviolet to soft X-ray radiation (22 - 1000 eV). It was based on a bending magnet radiation source for fast photon tuning in a wide energy range with a single grating monochromator similar in design to an SX-700. The spot size on the sample has a diameter of ~100 μm. Photoelectrons from the sample are analyzed by hemispherical electron energy analyzer.

Photon Source

The Materials Science Beamline uses radiation from bending magnet 6.1 at the Elettra storage ring. It provides to the beamline with polychromatic light in a wide energy range from visible to hard X-ray. Hard X-ray radiation is absorbed at the first mirror and then a monochromator selects light with a desired photon energy and bandwidth. The bending magnet radiation is mostly linearly polarized in the horizontal direction, with only a minor part of the radiation above and below the orbit having circular polarization. The Elettra storage ring parameters can be found here.

Beamline Layout

The beamline is based on grazing incidence reflective optics. All optical surfaces are gold coated. The first optical element is a toroidal prefocusing mirror that focuses the divergent photon beam from the bending magnet sagittally onto the entrance slit and tangentially onto the exit slit. It also absorbs all hard X-ray radiation.  The energy of photons is selected by a plane grating monochromator (PGM). Photon energy resolution is adjusted by the entrance and exit slit widths. From the exit slit the beam is focused again by the refocusing mirror onto the sample. Technical details of the optical concept of the MSB are described in [1].

MSB_scheme.gif

Last Updated on Wednesday, 21 December 2011 18:02