Microbunching Free Electron Laser

Advanced electron accelerators that utilize a plasma wave or wakefield to accelerate electrons need the incoming electrons grouped together into microbunches. These microbunches must have a length that is a fraction of the accelerating wavelength and a spacing that equals the period of the wakefield. Achieving these requirements would substantially increase the efficiency of the acceleration process and improve the quality of the accelerated electrons. However, existing sources for generating suitable microbunches are not available because the wakefield wavelength is typically on the order of 100s of microns, corresponding to THz frequencies. This project will develop a novel microbunching free electron laser (FEL) for producing microbunches suitable for feeding into a plasma-based accelerator. During Phase I, the design of the undulator for the microbunching FEL will be analyzed. The analysis will include detailed magnetic modeling, determination of the impact of the vacuum tube that also guides the THz radiation, and development of an engineering conceptual design for low-cost fabrication of the device. During Phase II, a prototype microbunching FEL will be built and tested. Commercial Applications And Other Benefits as described by the Applicant: The microbunching FEL would allow plasma-based accelerators to produce electron beams with sufficient charge and narrow energy spread. This achievement would enable table-top-sized accelerators to be used for industrial, medical, academic, and scientific applications. The microbunching FEL also could be modified to produce intense THz radiation, which has applications in such areas as security screening for homeland defense