Status and plans for the next generation magnetically immersed diodes on KITS

Sandia National Laboratories is investigating and developing high-dose, high-brightness flash radiographic sources. We are in the process of designing; fabricating and conducting engineering tests on the next-generation magnetically immersed electron diodes. These diodes employ unique, large-bore (80–110 mm), high-field (28–45 T), cryogenically-cooled solenoid magnets to help produce an intense electron beam from a needle-like cathode “immersed” in the strong Bz field of the magnet. The diode designs and status of the engineering development are described. Later this year we plan to conduct experiments with these sources on the new Radiographic Integrated Test Stand (KITS) [1], now in operation at Sandia. In its present three-stage configuration, KITS provides a 4-MV, 150-kA, 70-ns pulse to the diode. Fully three-dimensional particle in cell LSP code [2] simulations are used to investigate relevant physics issues and the expected radiographic performance (spot size and dose) of this system. Preliminary results from these simulations are described.