Use of a cavity-based X-ray free electron laser (CBXFEL) is potentially a way to dramatically improve the stability and coherence of existing XFELs. CBXFEL consists of low-emittance electron source, a magnet system with several undulators and chicanes, and an X-Ray cavity. The X-Ray cavity stores and circulates X-ray pulses for repeated FEL interactions with electron pulses until the FEL reaches saturation. The CBXFEL is expected to op-erate using 9.831 keV photons from LCLS, using synthet-ic diamonds as cavity Bragg mirrors. The LCLS copper linac will deliver two electron bunches 624 RF buckets apart, resulting in a total X-ray cavity length of 65500.87 mm. The final X-ray cavity design, assembly, and installation status will be presented in this paper.
Permanyer et al. (2026) studied this question.