Rectifier for RF Power Recovery

144 Rectifier for RF Power Recovery--Omega-P, Inc., 202008 Yale Station, New Haven, CT 06520-2008; (203) 458-1144 Dr. Jay L. Hirshfield, Principal Investigator Mr. George P. Trahan, Business Official DOE Grant No. DE-FG02-97ER82445 Amount: $75,000 A free-electron laser (FEL) is currently planned for the Department of Energy¿s Thomas Jefferson National Accelerator Facility for conducting advanced research. However, the FEL is inherently inefficient. As a result recovery of unused energy from the electron beam that powers the device is an important consideration in reducing the number of components and therefore cost and in reducing radiation doses. Energy recovery from the 1 MW, 200 MeV electron beam powering the FEL can be accomplished by causing the spent beam to decelerate and induce radio frequency (RF) power in superconducting cavities. This RF power must be extracted and rectified, so allowing it to be recirculated, thus increasing the electrical efficiency of the FEL. This project will perform computations and tests leading to a demonstration of efficient rectification of MW-level RF power using a cyclotron autoresonance accelerator (CARA) with a depressed collector. Preliminary estimates indicate that a ten-fold increase in FEL operating efficiency could result. During Phase I, tests of this CARA at power levels below its normal range of operation will be undertaken to determine if high conversion efficiency can be obtained. Calculations will also be carried out to enable a beam collector to be designed that can decelerate and intercept the CARA beam. In Phase II an appropriate depressed collector will be built and installed on the Omega-P CARA. Commercial Applications and Other Benefits as described by the awardee: Operation of an FEL for industrial processing can become much more efficient if effective beam power recovery can be incorporated. Annual cost savings from electricity conservation could thereby reach $0.5 million per 1 MW-hrs of energy used. Design of an efficient single-stage beam collector operating at a depressed potential can allow other devices using CARA beams such as those using high-power microwaves, to enjoy enhanced efficiency as well.