- Design of a 15MW Solid-State Linear Transformer Driver for Gas Switch Triggering ApplicationsSherburne, Michael (Virginia Tech, 2018-05-02)Field-reversed configuration (FRC) research and pulsed high-energy experiments are in a need of an upgrade. Studying nuclear fusion and obtaining high energy yields for flash x-ray radiography using plasma or particles can be made easier through faster switches. One newly emerging technology is called the Linear Transformer Driver (LTD). These switches are becoming more commonly used in the solid-state domain. While gas spark gap switches can supply high power, they cannot be turned off when engaged. Solid-state switches on the other hand can, and when integrated into the LTD topology, these switches can operate like their spark gap peers. Even better, solid-state switches can be switched in the sub-nanosecond regime with minimal jitter. With the advent of solid-state LTD technology, fast rise-time high energy applications in nuclear science and plasma physics experiments are possible. This has led to the design and development of a 30kV and 500A solid-state LTD. The designed LTD can achieve a rise-time under 10ns and has a high potential to achieve less than 1ns jitter. This thesis details every aspect of the LTD design process. A novel code has been developed to estimate the feasibility of a variety of solid-state switches and costs. This feasibility code has been shown to have a good correlation with real life prices that it models. A new detailed LTD model has been made as well and shows a strong correlation with other LTD models. The new model also shows voltage transient spiking of the pulsed waveform attributed by the primary inductance of the LTD. Overall, the design tools gathered and made in this thesis will help any engineer developing a solid-state LTD for their application.
- Wake Forest: Voices that Tell of a Faith CommunityCain Grim, Morgan (2014-11-04)A senior thesis project on the faith history of Wake Forest, an African American community in Montgomery County, Virginia. Includes transcribed oral histories, photos of churches and congregations, and previously collected documents about the community.