High-Speed Imaging of Exploding Detonators

Abstract

An experiment for imaging detonators used in explosively driven pulsed power applications with high-speed, short-exposure-time cameras will be described in the work to follow. Three, commercially available, high intensity, pulsed xenon light sources (> 10 <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">7</sup> candela intensity) yielded unsatisfactory image quality with a minimum exposure rate (~320 k frames per second). Above 320-k frames per second, the combined output intensity of the light sources was too dim. Due to this limitation, a lamp system was designed that would be capable of delivering higher light intensity to the target. Two types of lamp arrays were designed and tested. The first was a large lamp array comprised of a two high-energy flash lamps, while the second was a small lamp array comprised of many low-energy flash lamps. The large lamp array was intended for multiple shot use and was placed behind a protective sheet of polycarbonate to separate the bulbs from the detonator. The second small lamp array with low-cost flash lamps was intended for one-time use and will be placed closer to the detonator. Multiple five-stage, Rayleigh Pulse Forming Networks (PFNs) were developed to find the optimal energy for the flash lamp array. Each PFN was modeled using LTSpice circuit simulator to verify proper operation and help with optimization. Experimental measurements were taken of the PFN voltage and current outputs and compared to simulated values. A photodiode was used to measure relative light intensity from the different lamp arrays.