Technological Improvements in the DARHT II Accelerator Cells

The DARHT facility will employ two perpendicular electron Linear Induction Accelerators to produce intense, bremsstrahlung x-ray pulses for flash radiography. The second axis, DARHT II [1], features an 18 MeV, 2-kA, 2-microsecond pulse accelerator. DARHT II accelerator cells have undergone a series of testing and modeling efforts to fully understand their unacceptable initial failure rate. These R&D efforts are part of the DARHT 2^ndAxis Refurbishment and Commissioning project, and they have led to a better understanding of Linear Induction Accelerator technology and physics for the unique DARHT II design. Specific improvements have been identified and tested. Improvements in the cell oil region, the cell vacuum region, and the Pulse Forming Networks (PFNs) have been implemented in the prototype units that have doubled the cell’s performance. The prototype acceptance tests have been completed, and the lifetime reliability requirements were exceeded. The shortcomings of the previous design are summarized. The improvements to the original design, their resultant improvement in performance, and various test results are included.