TH3B3
University of Chicago, Chicago, Illinois, USA
ANL, Lemont, Illinois, USA
The X-ray free-electron laser oscillator (XFELO) has the potential to greatly surpass current SASE-FELs in terms of peak power and photon coherence. Although a large, 4th generation storage ring (4GSR) is promising as a diver for an XFELO operation, meeting the requisite electron energy spread remains a challenge. The transverse gradient undulator (TGU) is a potential solution to this issue*. Using low-gain TGU theory, we derive optimal beam parameters for a hypothetical XFELO in a straight section of PETRA-IV and discuss potential implementation challenges associated with the ring-FEL coupling, namely FEL beam degradation and gain modulation. The need for a by-pass and fast kickers is obviated by equipping a higher charge (4 nC) to sixteen equidistant electron bunches for XFELO interaction. RF is used to control the FEL duty cycle and allow the XFELO bunches to damp before resuming the FEL interaction. Detailed multi-stage numerical simulation was used to compute the projected performance**.
* T. I. Smith, L. R. Elias, J. M. J. Madey, and D. A. G. Deacon, J. Appl. Phys. 50, 4580 (1979).
** Y. S. Li, R. R. Lindberg, and K.-J. Kim, Phys. Rev. AB 26, p. 030702 (2023).
