Improved High-Current Injector Design

With the achievement of 2.1 kW CW IR operation and an upgrade to 10 kW undergoing commissioning, free-electron lasers (FEL) are now a serious option for high-power, military and commercial applications. As specifically identified in the recent "Department of Defense Laser Master Plan", the key technology issue on the path to high-power FEL deployment is the demonstration of reliable, high-brightness, photocathode injector operation. A DC gun/superconducting accelerator combination provides the most promising and most mature path to efficient, weapon-level electron beam power. One of the primary issues identified with this type of gun is beam quality degradation for operation at weapon system charge levels that approach 1 nC per bunch or higher. Longitudinal phase space aberrations set in that can significantly reduce the lasing efficiency of the FEL. We are proposing to design and build an accelerating system that will correct the development of this aberration and provide very high quality electron beams at current levels sufficient for weapon level performance.