Ambient Pressure Ultraviolet Photoelectron Spectroscopy (AP-UPS)
Ambient Pressure UV photoelectron spectroscopy (UPS) uses photons in the ultraviolet energy range, typically He I (21.2 eV) or He II (40.8 eV), to extract electrons from the valence bands of a sample at pressures in the mbar regime. In contrast to ‘regular’ UHV ultraviolet photoelectron spectroscopy, electron analyzers have to be adapted with differential pumping stages to be able to cope with the higher pressures in the setup. Beyond these more demanding requirements on the measurement hardware, ambient pressure UPS reveals the same kind of information as UHV UPS: high-resolution, high signal to noise spectra of the electronic valence states of the examined samples.
