DISCHARGE CHARACTERISTICS OF THE SPHERICAL INERTIAL ELECTROSTATIC, CONFINEMENT (IEC) DEVICE

The University of Illinois inertial electrostatic confinement (IEC) de vice provides 10(7) 2.5 MeV D-D neutrons/second when operated with a s teady-state deuterium discharge at 70 kV [1], Being compact and lightw eight, the IEC potentially represents an attractive portable neutron s ource for activation analysis applications [2], The plasma discharge i n the IEC is unique, using a spherical grid in a spherical vacuum vess el with the discharge formed between the grid and the vessel wall, whi le the -70 kV grid (cathode) also serves to extract high-energy ions, Two key features of the IEC discharge are discussed: 1) the breakdown voltage characteristics as a function of pressure-grid/wall distance ( pd), and 2) the formation of ion ''microchannels'' that carry the main ion flow through grid openings.