Single Shot Bunch Length Monitoring, Based on Interferometer and Novel THz Sensing

With the recent development of advanced photoinjector accelerators and next generation light sources, the progression towards high-current ultra-short beams is very important. Because the measurement of these short pulses with sub-ps time resolution is essential for successful beam operation, knowledge of the longitudinal profile and bunch length will be necessary, both for performance optimization and for benchmarking computational models. This project will develop a diagnostic to address an issue still remaining unresolved in ultra-short beams: bunch measurement on a single-shot real-time basis. Namely, a real-time bunch length interferometer will be developed utilizing a novel beam autocorrelation technique. In this approach, the interference of the beam takes place on the plane of a terahertz detector array, and the spatial interference is correlated to the horizontal position along the array. Commercial Applications and other Benefits as described by the awardee: A real time interferometer (RTI) would be of great use to the accelerator community as facilities progress towards ultra-short high-current science with stricter tolerances on beam parameters. Also, an RTI would be beneficial when incorporated into feedback loops to lock the bunch length of the beam, thus guaranteeing consistent parameter sets for the Free Electron Laser, and for Compton Scattering and collider facilities. The technique also should have numerous applications in the ever-growing field of terahertz radiation creation and imaging.