Performance of the VUV beamline 4.1 at the SRS, Daresbury Laboratory

The performance of a recently commissioned beamline, designated BL4.1, at the SRS, Daresbury Laboratory, is described. This beamline covers the energy range 15 ≥ hυ ≥ 200 eV, using a spherical grating monochromator, and is equipped with a UHV surface-science endstation containing a Scienta SES200 and an HA54 angle-resolving electron-energy analyser. Design param­eters and optical specifications are tabulated. Monochromator resolution has been determined by measuring the Fermi edge of a Pt foil cooled to 40 K and these values are compared with the calculated resolution. The flux delivered to the endstation has been measured directly using a calibrated photodiode. The performance of the beamline is further illustrated by reference to a study of the angular distribution of photoemitted intensity from a band-gap state on a TiO₂(110) 1 × 2 surface.