STABILITY OF AN INTENSE PULSED ION-BEAM DURING SUCCESSIVE OPERATION

Stability of an intense pulsed ion beam during successive operation wa s studied experimentally with an inverse pinch ion diode. When an anod e of metals or plastics is used for an ion source, the diode impedance and ion beam current were changed with every shot of operation. In th e case of a copper anode, the ion current at 10 shots was reduced to o ne-half or one-third that at the first shot. Using a soda-lime glass ( Na2O.CaO.5SiO(2)), on the surface of which vacuum oil or Aquadag was c oated as the ion source, the diode impedance and the ion current remai ned constant for 20-30 shots. With the vacuum oil ion source, the most dominant species of the ion beam was C3+, which has energy in the ran ge of 150-200 keV. The current density of the ion beam at 120 mm behin d the anode was about 100 A/cm(2).