This instrument was designed by Paul Kemper from the Bowers group for a collaboration with the Buratto group. The research involves generating size-selected metal clusters and depositing them onto semiconductor surfaces for examination by scanning tunneling microscopy and temperature programmed desorption. A description of the experimental setup can be found here on our collaborators web site. Instrumental details can be found in Kemper, P.; Kolmakov, A.; Tong, X.; Lilach, Y.; Benz, L.; Manard, M.; Metiu, H.; Buratto, S. K.; Bowers, M. T. Int. J. Mass Spec. 2006, 254, 202-209.