Advanced Line for Overlayer, Interface and Surface Analysis (ALOISA)

ALOISA is a multipurpose beamline dedicated to the chemical and structural characterization of surfaces, adsorbates and thin films in UHV conditions. ALOISA offers the possibility to perform in-situ photoemission and absorption spectroscopy in a photon energy range of 130-1500 eV, when the storage ring is operated at 2.0 GeV (minimum photon energy of 150 eV, when operated at 2.4 GeV). The end-station is equipped with a homemade hemispherical electron spectrometer mounted on rotating frames for performing photoelectron diffraction measurements. A dedicated channeltron is used to perform NEXAFS measurements by partial electron yield to enhance surface sensitivity. The six degrees-of-freedom manipulator is mounted coaxially to the photon beam in order to keep the sample at grazing incidence, while the oreination of the surface with respect to the linear polarization of the beam can be changed from p to s without changing the incidence angle. This non conventional scattering geometry together with a high level of automation and a dedicated software make Aloisa specially suitable to perform polarization dependent NEXAFS measurements and resonant photoelectron spectroscopy/diffraction.