Twenty kilovolts massive ion beam system for well-defined microcluster studies

We have constructed a new massive ion beam system for the studies on well-defined microclusters. The laser-ablation-type cluster source is equipped for cluster generation separated from the ionization system. Two types of ionization systems are prepared: an ArF-excimer laser (193 nm, 0.8 mJ/pulse, 3 ns) or F2-excimer laser (157 nm, 0.3 mJ/pulse, 3 ns) and an electron impact ionizer. The energy and charge state of cluster ions are analyzed with a high accuracy by the sector-type 60° electrostatic analyzer with an orbital radius ρE=200 mm. The size of clusters with a specific energy and charge state is defined by the 60° magnetic analysis system characterized by an orbital radius ρM=650 mm and the maximum field strength Bmax=1.4 T. The massive ion beam system enables one to provide well mass-selected stable clusters, e.g. CuqN with sizes ranging as follows N=1–31 for q=+1 at energy E=20 keV, N=10–63 for q=+2 at E=40 keV, N=44–94 for q=+3 at E=60 keV, and N=121–126 for q=+4 at E=80 keV.