A differentially pumped electrostatic lens system for photoemission studies in the millibar range
Rev. Sci. Instrum. 73, 3872 (2002)
D. Frank Ogletree, Hendrik Bluhm, Gennadi Lebedev, and Charles S. Fadley, Zahid Hussain, Miquel Salmeron
RevSciInstrum73-3872