Advanced High-Brightness Electron Source

High-repetition-rate (>1 MHz), high-bunch-charge (up to 1 nC) electron sources, possessing the high gradients at the cathode surface that are needed for low emittance electron bunches, are critical components of next generation light sources, such as energy recovery linacs (ERLs) and free electron lasers (FELs), and are essential for other advanced accelerator applications. The high-brightness injectors required by these advanced light sources are key elements on the path to full operational capability, due to the state-of-the-art emittance required to achieve desired performance levels (= 1 mm-mrad at appropriate bunch charge values). This emittance is primarily determined by the performance of the injector. This project will develop and test an Oxygen Free Electronic (OFE) copper, radio frequency (RF), photocathode gun that can operate with continuous wave RF at a cathode gradient in excess of 10 MV/m, thus producing low emittance electron bunches at high repetition rates. Phase I will analyze the feasibility of the injector concept, which would then be built in Phase II. Commercial Applications and other Benefits as described by the awardee: The primary application of the resultant accelerating structure would be for ERLs. The electron source also could be used in other radiation sources to produce high-power coherent radiation, spanning THz to UV and perhaps beyond, through various mechanisms such as coherent synchrotron radiation and FELs. Finally, the source could find application in defense and as the front end of high-power electron accelerators for materials processing and sterilization.