A monochromatized multiple energy laboratory UV source for k-space imaging

A laboratory set-up for ultraviolet (UV) photoelectron spectroscopy combining a high intensity UV source and a toroidal UV monochromator, both being commercially available, is described. The source is modified in order to maximize the solid angle collected by the monochromator. Scanning its exit arm length allows for the optimization of the photon intensity as well as the energy resolution by minimizing the defocus term only. By using several different gases such as He, Ne or H2 one obtains a powerful tool to sample extended regions in k-space. Fermi energy maps are presented for Cu(110) in the photon energy range from 10.2 to 48.3 eV. As a result of the variable photon energy an actual zooming into the well-known Shockley surface state is possible.