URANOS - Ultra Resolved ANgular phOtoelectron Spectroscopy beamline (former UARPES) - allows for measurements of fundamental quantities, i.e. the energy and the momentum, describing a photoelectron state in the space outside the solid sample.

If a spin selector is used additionally, a complete set of quantum numbers for the electron may be obtained. Then, within a so called sudden approximation, the electron energy, momentum and spin measured over the sample surface may be related, to binding energy, quasimomentum, and spin, that the electron had in the solid before the photoelectric event took place. Thus the electronic band structure of the studied solid is obtained experimentally. Beside this simple picture ARPES gives also detailed insights into complex electron – electron and electron – lattice interactions in the solid.

The importance of the ARPES technique for contemporary science and technology is widely recognized. Dedicated ARPES beamlines exist at almost all synchrotron radiation centers worldwide.

Applications:

Many recent advances in materials science have been enabled by better understanding of the electronic structure of complex systems, gained due to ARPES studies. Examples include advances in fields such as:

• high temperature superconductivity
• topological insulators
• graphene physics.

The beamline team:

• prof. dr hab. Jacek Kołodziej, the Jagiellonian University, the Faculty of Physics, Astronomy and Applied Computer Science
• dr Natalia Olszowska, the SOLARIS Centre
• mgr Marcin Rosmus, the SOLARIS Centre.

Scientific supervision over the bamline is provided by the Synchrotron Radiation Department of the Marian Smoluchowski Institute of Physics at the Faculty of Physics, Astronomy and Applied Computer Science of the Jagiellonian University.

Beamline optical scheme:

Beamline parameters:

Parameters:	Value:
Source	Elliptically polarizing undulator (EPU) APPLE II type, quasiperiodic. Magnetic period length: 120 mm.
Available energy range	total: 8–100 eV NIM: 8 eV–30 eV PGM: 16 eV–100 eV
Light polarisation	Linear vertical, linear horizontal, circular, eliptical. Linear skewed. For the linear skewed polarisation the lower energy limit is 12 eV.
Resolving power (RP)	20 000
Beam size at sample (H x V)	NIM: 350 μm x 60 μm PGM: 270 μm x 30 μm
Photon flux at a sample	min. 5 x 1011 photons/s @ 20 000 RP
Available techniques	Angle-resolved photoelectron spectroscopy (ARPES) at sample temperature 8–500 K, low energy electron diffraction (MCP-LEED), Auger electron spectroscopy (AES).
Electron spectrometer energy resolution	1.8 meV
Angular resolution	0.1°
Available sample preparation techniques	Cleaving, thermal annealing up to 1800 K, Ar+ ion bombardment, thin firm growth, surface reactions in the gas phase.