BUNCH COMPRESSION AND THE EMITTANCE GROWTH DUE TO CSR

One of the notable features of the Energy Recovery Linacs (ERLs), as compared to the other type accelerators, is the synchrotron radiation from the extremely short electron bunches. We have a plan to produce extremely short electron bunch in a test ERL for the future ERL project in Japan. In the test ERL, wakes due to coherent synchrotron radiation (CSR), which is generated by short electron bunches at the arc section, are critical for keeping low beam emittance and short bunch length. In this paper, we describe a technique to suppress the emittance growth due to CSR and present the results of optimizations of the arc section for the test ERL