Rugged High Current Cathode for Modular Accelerators

A robust high current cathode will be developed for use with a rugged, high-reliability portable accelerator. The high-power density afforded by the high brightness cathode allows the accelerators to be used in place of gamma ray irradiators. Safe reliable accelerators replace the use of radioactive sources for irradiation in a variety of applications. During Phase I, a prototype cathode will be demonstrated that provides high average current density. The pulsed non-thermionic cathode will operate at near room temperature avoiding the high thermal load of thermionic cathodes and avoiding the use of active cooling to operate at high- power density. The cathode does not involve any low work function materials that would be susceptible to traces of reactive gas thus relaxing the base pressure required for operation. It also largely eliminates the potential of back ion bombardment that would typically erode emitter materials. No sharp tip arrays are employed simplifying fabrication. The cathode employs simple planar structures so that fabrication and assemble is easy. Downtime to replace the cathode is very short, not hours or days as is the case with more commonly used cathodes. The rugged cathode will be used in accelerators required to deliver high dose rates that depend upon high current density cathodes.