PPPS-2013: A robust, low-inductance, low-jitter switch for petawatt-class pulsed power accelerators

Spark gap switches are integral components in pulsed power applications ranging from pulsed microwaves and flash x-ray sources to, more recently, the linear transformer drivers (LTDs) powering next-generation petawatt-class pulsed power accelerators at Sandia National Laboratories (SNL) in Albuquerque, New Mexico. An LTD system uses a triggered switch to conduct current from two capacitors to form a magnetic field which accelerates particles down magnetically insulated transmission lines (MITLs). Existing spark gap switches suffer from limited lifetimes ¹ and levels of jitter and inductance in excess of what will be required for these new accelerators². Kinetech, under a contract from SNL, has designed, developed, and demonstrated a switch that exceeds all of the established requirements³ by firing for 57,200 shots with an inductance of 35 nH and a one-sigma switch jitter of 1.2 ns variation over a 1,000 shot sampling after 1k, 25k, and 50k shots. This paper will detail the design, development, and demonstration of this switch by Kinetech and SNL.