Developing an undispersed VUV beamline for large area surface processing

A versatile windowless beamline for undispersed VUV radiation in the energy range between 10eV and 100eV is presented. An adjustable light guiding assembly with two glass capillary arrays as vacuum interfaces is constructed to assure high optical transmission (about 30%) of white synchrotron light. Three differential pumping stages reduce the pressure of a reaction gas from 1 mbar to 5 x 10 high 9 mbar. Estimate of the optical transmission of the system are given. The beamline was designed to irradiate a large area of a semicoanductor surface for synchroton photon enhanced etching and depositon processes.