Direct Imaging of Static and Dynamic Ion Cloud Distributions in an Electron
Beam Ion Trap

James V. Porto
Div. 842, Physics Laboratory

We have used long-lived uv transitions in the ground term of Ar13+, Xe31+ and Xe32+ to directly image highly charged ions within an electron beam ion trap (EBIT). Using an intensified CCD camera, we have the capability to measure both static and dynamic ion cloud distributions. The technique provides information about the distribution of trapped highly charged ions which is difficult to obtain by other methods. Static images can be used to determine ion temperatures and the degree of overlap between the electron beam and ion cloud. Dynamic images are sensitive to electron-ion heating rates, ion-ion collision rates and the dynamics of cross field diffusion. The new information can eventually be used to test and improve detailed models of ionization balance and ion cloud dynamics within the EBIT. Combined with improved modeling, experiments like these can be used to assist a wide variety of measurements of atomic data in electron beam ion traps, particularly those involving charge changing cross sections.