Thyristor based solid state switches for thyratron replacements

Thyratrons and spark gap switches continue to be the predominant technologies used for high current, high voltage pulsed power applications. The offerings from thyratron manufacturers have been diminishing and prices have increased as vacuum tube manufacturing continues its decline. In addition, the maintenance requirements for thyratrons make them unsuitable for many potential main stream applications for pulsed power. High voltage IGBT based switches have become common, but current limitations have prevented them from being an attractive alternative for many thyratron replacement applications. Thyristors have the advantage of high current capacity and this paper will describe compact, high current, high voltage solid state switches for thyratron replacements, based on thyristor technology. The switches are based on series connected fast thyristors with 3cm² die in a 20cm² package. These switches have been tested to 50 k V, to greater than 12 kA, to greater than 50 kA/μs, to 360 Hz, and to 3×10⁸ pulses, without failure. Thyratron replacement switches based on thyristor technology are currently in use at CERN, Argonne National Lab and SLAC National Accelerator Laboratory. They offer advantages over thyratron switches for cost, lifetime, size, weight and maintenance requirements.