A new family of isochronous arcs [CLIC accelerator]

For the Compact Linear Collider (CLIC), the bunch time structure should be preserved in the injector complex, especially in the recirculation arcs and after the final bunch compression stage up to the main linac injection. At the same time, because the transverse emittances are so tiny, their growth, essentially due to synchrotron radiation, should he kept as low as possible. In other projects, several isochronous arcs have been designed numerically to meet these requirements for a particular arc layout. These designs cannot be easily adapted to different configurations. The purpose of this study is to obtain analytically the main parameters of a new class of isochronous arcs which can be quickly tailored to special applications. Some of these are presented and they emphasize the small transverse emittance growth achievable even at large injection energy while keeping the are radius in a reasonable range. Because locally the first-order anisochronicity is fully cancelled, higher-order contributions are less important than in other designs.