A New Robust One-Shot Switch for High-Power Pulse Applications

Abstract

High Voltage (HV) switches capable of operating at high speeds and over a wide range of voltages and energies are used in a variety of pulse power applications in material science and plasma physics. Of particular interest is the use of small-scale capacitor discharges to measure the electrical properties of materials as they are heated from solid through liquid to a gas phase. In a capacitive discharge unit (CDU), energy stored in a capacitor is coupled through a switch into a low-impedance transmission line, which typically terminates with a thin sample of material. The energy coupled to the sample is sufficient to cause vaporization. Voltages in such systems range from a few volts to thousands of volts. These vaporized materials are used either as plasma sources for physics experiments, or to propel a thin layer of electrically insulating polymer for high-pressure-impact studies. Several types of switches have been used to drive these systems, including triggered spark gap, dielectric breakdown, and mercury vapor switches. A wide variety of solid-state devices, such as the insulated gate bipolar transistors, are also being utilized for these applications. Inducing a high-pressure shock wave in a dielectric to produce a transition from dielectric to conductor has also been used as an efficient single-shot switch for capacitor discharges. The high-voltage micro-machined switch presented in this document has been designed as a single-use alternative to the more expensive triggered spark gaps and solid-stage devices. The plasma-bridge switch is intended for large-volume, relatively inexpensive systems, and a cost-effective switch for use in destructive testing.