SBIR-STTR Award

Current state-of-the-art, high voltage, pulsed power systems designed to drive high power microwave (HPM) sources utilize Marx generator designs. The high voltage insulation of these devices has been traditionally based on either high dielectric strength oil or sulfur hexafluoride (SF6). The dielectric strength of the insulating medium determines the minimum size of the tank enclosure of the Marx generator since it determines the maximum voltage standoff between the fully erected Marx output voltage and the tank wall. We propose to develop an advanced insulating technique based on our patented nested high voltage generator. This technique uses solid insulation with field grading foils that minimized the distance from the fully erected voltage and the tank wall. This proposal describes such a device, expected space savings, and how we plan to model, build, and test a unit based on this construction.

Benefit:
The potential decrease in volume by 40% of high voltage pulsed devices due to this technology makes possible smaller, light-weight payloads for airborne HPM equipment. This can also be used in commercial high voltage applications such as pulsed x-ray or electron beam equipment. This is also beneficial in any mobile pulsed high voltage application where size and weight are critical design factors.

Keywords:
Nested High Voltage Generator, Electric Field Grading Foil, Solid Insulation, Marx Pulse Forming Network

Current state-of-the-art, high voltage, pulsed power systems designed to drive high power microwave (HPM) sources utilize Marx generator designs. The high voltage insulation of these devices has been traditionally based on either high dielectric strength oil or sulfur hexafluoride (SF6). The dielectric strength of the insulating medium determines the minimum size of the tank enclosure of the Marx generator since it determines the maximum voltage standoff between the fully erected Marx output voltage and the tank wall. For example, AFRL has found that insulating an eight-stage linear configuration Marx generator employing 100 kilovolt capacitors requires nearly 50 pounds per square inch gauge (psig) of SF6 to insulate a six centimeter distance between the capacitors and the tank wall. In phase I we demonstrated that the "Nested High Voltage" insulation geometry can successfully be used to insulate the voltages required while being compatible and convenient for the production of the pulses required. We propose to implement our "Nested Generator Insulation" at full scale in order to reduce the size of 500 kV class HV generators to a diameter of 35 cm or less. This solid insulation technique uses field grading foils that minimized the distance from the fully erected voltage and the tank wall. That distance can be reduced by more than 50% to less than three centimeters in successful NHVG style designs. This proposal describes the implementation of the Nested technology in order to produce a full sized test device based on the technology. That device will be delivered to AFRL with a 500 kV, 10 kA nominal output under load and an outer diameter of roughly 35 cm.

Benefit:
The NHVG technology is the subject of active commercialization in its DC embodiment. We see potentials for the integration of the pulse generator with the DC NHVG in areas such as RF accelerators for cancer therapy, security, and medical sterilization. In such an embodiment, the Klystron and pulse system would be integrated together with switching provided by the grid of the electron gun. The customers would be suppliers of Cancer therapy machines such as Phillips, Varian, Seimens, and Mitsubishi. Security application are in cargo inspection.

Keywords:
Nested High Voltage Generator, Electric Field Grading Foil, Solid Insulation, Marx Pulse Forming Network, Field Graded Insulation