High Charge per Bunch RF Gun Photocathode

A definitive experimental study of cathode design and photoemissive materials for normal-conducting RF injectors is proposed. The University of Maryland (UMD) and Brookhaven National Laboratory (BNL) have agreed to collaborate with Advanced Energy Systems (AES) on this project. As an FFRDC, BNL will not receive any SBIR funding but has agreed to provide access to its existing facilities and equipment thereby providing great leverage to the program. In Phase I, UMD will perform proof-of-principle tests of their novel proprietary cathodes and BNL will study alternate high-quantum-efficiency cathode materials. Only those materials that emit with visible light will be considered. AES will design a cathode preparation chamber, compatible with UMD and BNL cathodes, for integration with a BNL high-power RF gun. In Phase II, the preparation chamber will be fabricated and interfaced to the exisitng 703 MHz RF gun, photocathode drive laser and 1 MW CW RF power supply at BNL. High-average current tests of specific UMD and BNL cathodes will then be performed. Target performance for this Phase II demonstration is a continuous average cathode current approaching one Ampere.