Practical long-life spark gaps for high-reliability applications

Lifetimes of 10⁷ to 10⁸ shots have been demonstrated for small triggered spark gaps switching over 3 J/shot, and an average lifetime of 3.5×10⁶ shots has been demonstrated for a larger gap switching over 160 J/shot. Average misfire ratios well below 1% have been achieved, with 0.1-0.5% being typical for a significant fraction of the gaps´ useful lifetimes. The authors discuss the goals of the IR and D program that led to the successful development of these gaps, the failure mechanisms that had to be overcome to achieve the desired performance, the life tests that were conducted, and the performance levels that were ultimately achieved. In addition to a long service life, the requirements of some systems mandated a very low rate of misfires. While 0.5% was deemed adequate, a misfire rate of less than 0.1% was achieved for gaps capable of 10⁸ shots at substantial levels of switched energy and conducted charge