Simulation studies of optimized electrode designs for a cylindrical IEC

Summary form only given. The cylindrical version (c-device) of the single grid inertial electrostatic confinement (IEC) device is of strong interest for various neutron activation analysis (NAA) applications. The present version produces /spl sim/10/sup 6/ D-D fusion neutron/s steady-state, and a higher yield pulsed version is under development. In both designs the grid configuration must be optimized for maximum neutron yield. An ion tracking code, SIMION, has been adapted for this purpose. While it includes several key approximations (e.g., neglects self-fields and collisions), it still predicts trends well for the present regime of operation, and provides improved physical insight. Recent simulations have examined variations of the reference electrode design, covering a wide range of diameters and lengths. Thus, for example, with a 10-cm long cathode and 3-cm long anodes the optimum diameter is predicted to be 60-80 mm. As the diameter is reduced further, the ion beam focus is lost. Further, the plasma sheath at the inside cathode wall begins to distort the beam path. These simulations will be described along with results for several novel designs, including a modular cathode and multiple "segmented" electrode concept will be presented.