FIRST RESULTS FROM THE HIGH-ENERGY RESOLUTION PHOTOEMISSION BEAM LINEAT ELETTRA

We report the first results obtained from the high energy resolution b eam line at the storage ring ELETTRA of Trieste. The beam line has bee n designed to perform photoemission experiments in the vacuum ultravio let (VUV) and soft X-ray (SXR) energy range. The radiation source is a n undulator which consists of three sections, with 36 periods and a pe riod length of 12.5 cm. It allows scanning of an energy range 17-900 e V using the 1st, 3rd and 5th harmonics. The monochromator is a spheric al grating type and the resolving power at 400 eV, estimated from the K-shell photoabsorption of the N-2 molecule is well above 10 000. The spectra are better than any other spectra taken while operating with h igh flux, i.e. first order diffraction and grating not masked. Measure ments taken at the oxygen and neon K-edges, the argon L(2,3) edges and of the helium double ionization spectra, indicate that the resolution is excellent from 65 to 870 eV.