Short pulses are central to many next generation light source initiatives that are typical of linear accelerators. Here, the electron beam output from the bunch compressor will be left with a small chirp to compensate for wake field effects through the rest of the linac. This residual chirp can be detrimental to things such as FEL performance and must be removed. This energy compensation was realized by a simple wake field device, designed and built by Euclid Techlabs and first demonstrated at the ATF in 2011.
More recent developments saw Euclid design and test a tunable device for energy chirp compensation. The design consists of two parallel dielectric lined plates and can be shown to reduce the energy chirp, as in the figure above. The image is that of the beamline spectrometer showing the energy spread of the beam after it has passed through the chirp compensator. Each beam picture is for a different amount of separation of the parallel plates, the top is where no compensation was applied (plates far apart) and the bottom is with maximum chirp correction (plates close together).
For more detailed results and experiment information, please see the following publications