Recent progress in DoD's program to develop Ar K-shell X-ray radiation sources

The Decade half X-ray radiation simulator will combine the outputs of eight synchronized modules to produce a current of up to 13 MA delivered to a short circuit load in /spl sim/300 ns. Decade is located within the Decade Radiation Test Facility (DRTF) at the Arnold Engineering Development Center, Tullahoma, TN. Decade's output will be used for nuclear weapons effects testing; the DRTF will reach initial operational capability (IOC) in 2007. DoD's X-ray radiation simulator R&D program is focused on maximizing 3.1 keV X-ray fluence from Decade's argon z-pinch. Electric current risetime will be approximately a factor of 3 longer than typically used to drive plasma radiation source (PRS) loads. Scaling to longer current risetime is advantageous in terms of reduced driver cost and complexity. The use of longer pulse drivers, however, requires an increase in the initial diameter of the z-pinch gas puff. The unique challenge is to extend the success with 100 ns current risetime simulators into the realm of the 300 ns current risetime of Decade. As the diameter is increased, increased asymmetry and instability can limit the ability of the load to produce K-shell radiation efficiently. These effects were largely un-quantified until technical investigations were conducted under the auspices of the simulator R&D program. This paper discusses progress, activities and issues in developing the large diameter z-pinch for Decade.