Diversified Technologies, Incorporated of Bedford, MA is building a solid state, 95kV, 21A, fast opening series switch for the Advanced Light Source (ALS) at Argonne National Laboratory under a DOE Phase II SBIR (Small Business Innovation Research) grant. The new switch replaces a mercury ignitron crowbar, resulting in substantial improvements in system operation.

- First, the operating time of the solid state switch, including arc detection and switch opening, is 700ns, much faster than a crowbar.
 - Second, much less current is carried by the opening switch than by a crowbar.
 - Third, the high voltage can be turned back on as soon as the arc clears (<<1 ms)
 - Fourth, an opening switch does not use environmentally-hazardous mercury.

In a pulsed system, the same switch can serve as both a pulse modulator and arc protection system. In addition, the technology can be used for high voltage power supplies. In this paper, DTI will describe the architecture of the opening switch, the current status of research and construction, and the applicability of this solid state technology for power supplies and modulators.