An asynchronously operating ERL-ring type collider proposal for the TAC particle factory and SASE FEL facility

A SASE FEL facility was first proposed in Feasibility Report of the TAC project in 2000. Main goal of the proposal is, to cover VUV and soft X-rays region (tunable, 1-100 nm) of the spectrum besides IR-FEL, Bremsstrahlung and Synchrotron Radiation proposals of TAC. It was planned that, 1 GeV electron linac of the linac-ring type collider sector of TAC, should asynchronously be used as a driver for the SASE FEL facility. On the other hand, a more promising option, namely ERL, is arising nowadays for both collider and SASE FEL proposals of TAC. Today, ERLs provide a powerful broad range of applications like: electron cooling devices, high average brightness, high power FELs, short-pulse radiation sources and high luminosity colliders. Because of the high luminosity (∼ 2.3x1035 cm-2s-1) requirement of the TAC collider and high peak power (∼ 2-3 GW) and high average brightness (∼ 1025-1030 photons/s/mrad2/mm2/0.1%BW) requirements of TAC SASE FEL, 1 GeV electron accelerator sector of the collider should be based on an Energy Recovery Linac. Especially, the average brightness value mentioned above, exceeds the rest of the light sources (existing and proposed) by about 5 orders of magnitude. The asynchronously ERL operation option for both collider and SASE FEL, is still under discussion and Research and Development stage. Finally, this study points out the feasible linac options for the SASE FEL facility proposal of TAC. In addition, asynchronous operation is discussed for a special RF linac or an Energy Recovery Linac. Furthermore, optimization study results of SASE FEL are mentioned.