ABSTRACT
We have produced C60 ion beams by combining plasma sputtering and laser ablation. A C60 sample was placed in an electron cyclotron resonance type ion source, negatively biased and sputtered by argon plasma. The beam current of C60 (+) decreased rapidly, but it was transiently recovered by a single laser shot that ablates the thin sample surface on the sputtered area. Temporal variations in beam current are reported in response to laser shots repeated at intervals of a few minutes.
ABSTRACT
Beam intensity fluctuation was investigated using an electron cyclotron resonance ion source of an all-permanent-magnet type under development for highly stable beam intensity. While the source achieved a stability of better than 3.2% by strict regulation of the coolant temperature change within +/-0.1 degrees C, the intensity varies strongly with intentional changes in the temperature of the plasma chamber coolant. The influence of the temperature on chamber expansion, magnetic field strength, and vacuum was measured or estimated in detail. The result shows that a slight change in vacuum and magnetic field strength has considerable influence on the intensity fluctuation.
