Design Studies of Damping Wigglers for PETRA IV at DESY

Abstract DESY plans to upgrade the present PETRA III facility into a high-resolution 3D X-ray microscope for chemical and physical processes - the future project PETRA IV. The highest spatial resolution for all X-ray techniques will be ensured by focusing the synchrotron radiation on the smallest spot. For this purpose, a 20 pmrad beam emittance is aimed. The Damping wigglers (DW) will be used in the PETRA IV storage ring to reduce the transverse phase space of the electron beam by damping the emittance and increasing the brilliance of the light. Both fixed gap and variable field DWs are planned to compensate for the insertion device-induced emittance change over time. DWs have been successfully used in PETRA III to achieve a record emittance of around 1.4 nmrad. For PETRA III, only fixed gap DWs were used. This paper presents detailed design studies for the PETRA IV DWs.