Load line evaluation of a 1-MV linear transformer driver (LTD)

The linear transformer driver (LTD) is a promising new pulsed power technology with applications including high voltage flash X-ray radiography and high current Z-pinch drivers. A LTD cavity is similar to a traditional inductive voltage adder (IVA) cavity, however the primary energy storage is packed inside the cavity. The resulting architecture is more compact than a traditional Marx generator driven IVA. Test results of a 1-MV LTD voltage adder with a large area electron beam diode over a range of impedances is described. The 1 -MV LTD is designed to supply 125 kA in a 100-ns FWHM voltage pulse without the optional peaking capacitors. A single cathode stalk is threaded through the centers of the seven series cavities forming a coaxial magnetically insulated transmission line (MITL). The MITL is terminated with a large area electron beam diode that produces a 75-ns FWHM X-ray pulse. Flash radiography accelerators are typically designed to operate at a single output impedance but are expected to drive various diodes with dispirate impedances. As a result, the diode impedance is not always well matched to the accelerator. Experiments with large area electron beam diodes of varying impedance were used to evaluate the performance of the 1-MV LTD under loads similar to radiographic diodes.