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

A laboratory set-up for ultraviolet (UV) photoelectron spectroscopy combini ng a high intensity UV source and a toroidal UV monochromator, both being c ommercially available, is described. The source is modified in order to max imize 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 dif ferent gases such as He, Ne or H-2 one obtains a powerful tool to sample ex tended regions in k-space. Fermi energy maps are presented for Cu(110) in t he photon energy range from 10.2 to 48.3 eV. As a result of the variable ph oton energy an actual zooming into the well-known Shockley surface state is possible. (C) 1998 Elsevier Science B.V. All rights reserved.