Inverse free electron laser accelerator development

The theoretical study of Inverse Free Electron Lasers (IFEL) as a potential mode of electron acceleration has been pursued at Brookhaven National Laboratory(BNL) for a number of years. As part of this program a proof-of-principle experiment with a single module accelerator unit has been recently successfully carried out. The IFEL accelerator made use of the 40 MeV linac beam and high power CO₂ laser beam of the Accelerator Test Facility (ATF), at BNL, in conjunction with a fast excitation, tapered period, wiggler. Basic aspects of the design of this single module IFEL accelerator will be presented, together with the experimental results of ΔE/E as a function of the IFEL parameters. Comparison with analytical and 1,3-D numerical simulations clearly establish the IFEL character of the electron-EM wave energy exchange, permitting thereby scaling to higher laser power magnitude and acceleration gradients. In addition, planned near term IFEL accelerator development will be indicated, incorporating the use of the IFEL as a beam prebuncher preceding a Inverse Cherenkov Accelerator, and the use of two IFEL modules in cascade in order to more realistically test the feasibility of a multi-module IFEL accelerator