Beamline Description
The interconnected set of UHV chambers includes state-of-the-art surface preparation and survey (Ar ion sputtering, annealing, controlled evaporation, LEED/Auger characterization), atomic resolution scanning tunneling microscope (STM), and two spectroscopic end stations connected to two distinct beamlines.
Photons with variable choice of polarization are emitted by two non-collinear Apple II type insertion devices. The low energy beamline (APE-LE) covers 10-100eV photon energy range dedicated to high resolution ARPES and Spin-ARPES; the high energy beamline (APE-HE) covers 200-1600 eV photon energy range used for XAS, XMCD, XMLD, XPS, in-operando and near-ambient-pressure spectroscopies. Both end stations are equipped with cryostats (minimum sample temperature during the measurements is 15 K (30 K) at APE-LE (APE-HE)).
The ARPES-dedicated low energy end station hosts Omicron-Scienta DA30 electron energy analyzer that operates in deflection mode and allows for detailed k-space mapping at fixed sample geometry (fixed angle). The total measured energy resolution (analyzer, temperature, photons) is ~6meV, while the angular resolution is <0.2°. The analyzer is complemented with VESPA (Very Efficient Spin Polarization Analysis) that consists of two VLEED-based scattering chambers for the determination of spin direction of the photo-emitted electrons, becoming the first facility for spin-resolved ARPES at Elettra.
The high energy end station hosts complementary spectrometers allowing for soft-X-ray absorption (XAS), magnetic dichroism (XMCD, XMLD) and X-ray photoelectron spectroscopy (XPS). Samples can be loaded into the APE system via two differentially pumped load-locks and then transferred in UHV to any of the preparation chambers, to STM and to both end stations. APE also allows the integration of users' specialized sample growth chambers, which may be connected to the main sample distribution chamber and have full access to the off-beam and on-beam facilities.
APE beamlines and APE laboratory are illustrated below. For detailed description, please see: Rev. Sci. Instrum. 80, 043105 (2009); doi:10.1063/1.3119364.
