High Voltage Solid-state Trigger for HEDP Applications

Precision triggering of pulsed power is critically important for the study of high energy density plasma physics at experiments like the Z Machine located at Sandia National Laboratories. The current trigger generators used at Sandia are marginally reliable and have a long delivery time from their manufacturer due to the thyratron inside, and there is concern about the long-term availability of these thyratrons. When measured over short timescales, thyratrons typically have a jitter of a few nanoseconds; but over longer timescales, they can have a much larger drift. Additionally, thyratrons need stable, high-current, low- voltage power sources, have long warm-up times, and require conditioning shots to achieve a stable operating point. Eagle Harbor Technologies (EHT), Inc. is proposing to develop a solid-state thyratron replacement that can be used to trigger higher voltage spark-gap switches at Sandia and other laboratories. EHT will utilize previously-developed capabilities in series stacking of solid-state switches combined with our expertise in nonlinear transmission lines (NLTLs). The combination of these technologies should allow for the development of a low-jitter solid-state trigger generator that can produce pulses with fast rise times. In the Phase I program, EHT will develop a first-generation prototype solid-state thyratron replacement. EHT will conduct a trade study of solid-state switches to balance current-carrying capability, voltage, rise time and cost. NLTL materials and construction techniques will be evaluated. EHT will design, build, and test a series stack of solid-state switches and NLTL to demonstrate fast rise-time pulses into 50 Ω. The Phase I results will be used to produce a preliminary design of a solid-state thyratron replacement that can be built and tested at Sandia in a potential Phase II program.The Z machine and its successors provide a venue for scientists to study high-density and high-pressure environments found nowhere else on earth. A solid-state thyratron replacement is important to improve the reliability and robustness of these expensive, large-scale physics experiments. Improved triggering would decrease the likelihood of mis-fires, which would reduce the risk of damage to expensive equipment. This reduced risk will allow public funding to be more effectively spent on conducting science rather than rebuilding equipment damaged due to a mis-trigger. These switches also have applications in plasma generation, pulsed electric fields, and high-power microwave generation.