KIT, Karlsruhe, Germany
While recent diffraction-limited storage rings provide bunches with transverse dimensions smaller than the wavelength of the observed synchrotron radiation, the bunch compression in the longitudinal plane is still challenging. The benefit would be single cycle pulses of coherent radiation with many orders of magnitude higher intensity. However, the self-interaction of a short electron bunch with its emitted coherent radiation can lead to micro-bunching instabilities. This effect limits the bunch compression in storage rings currently to the picosecond range. In that range, the bunches emit coherent THz radiation corresponding to their bunch length. In this paper, new measurement setups developed at the Karlsruhe Institute of Technology are described for systematic turn-by-turn investigations of the micro-bunching instability. They lead to a better understanding thereof and enable appropriate observation methods in future efforts of controlling and mastering the instability. Furthermore, the described setups might also be used as high repetition rate bunch compression monitors for bunches of picosecond length and below.
