NIF solid-state switch pulse generator optimization for multi-pulse operation

A solid-state high voltage pulse generator developed as part of the Advanced Radiographic Capability (ARC) mission for the National Ignition Facility (NIF) has been deployed. This paper will provide details of the pulser design and the upgrades required to achieve reliable operation for multi-pulse bursts for an ever-increasing mission space. The pulser design has been demonstrated to be robust, reliable and to meet all performance specifications as they apply to the Plasma Electrode Pockels Cell (PEPC). This pulser is realized as a FET-driven twenty-seven stage magnetic adder operating with 700 volt primaries. It delivers a programmable multi-pulse burst of 18 kV, 3 kA pulses to a PEPC at repetition rates up to 1 Hertz. The typical pulse widths are 200ns with 20ns rise-and-fall-times at the pulser. A capacitive load, significant cable lengths between pulser and Pockels cell, fast transition times, and the microsecond type delays between pulses lead to non-ideal interactions that must be addressed to limit pulse distortion and reduce stress on the pulse electronics. In this paper we discuss the various options considered for resolving these issues, down-select decisions, and test results that demonstrate improvements.