Modification to the Long Pulse Ion Source for operation on the Tokamak Physics Experiment (TPX)

The 12/spl times/43 cm Long Pulse Ion Source was designed for a 2 second beam pulse duration at the 120 kV, 70 A D/sup +/ level. While the accelerator grids and most of the plasma chamber are designed for DC operation, the back plate ("electron dump") was designed for pulsed operation. Replacing the central region of the back plate with an actively cooled insert will allow full DC operation. Cooling passages within the insert were designed to keep the required inlet and exit pressures at current levels.