“…By means of a beam manipulation technique previously pioneered at the A0 Photoinjector, called Flat Beam Transformation (FBT), the ratio of transverse emittance can be heavily coupled to produce an output emittance of ( nx , ny , nz ) = (10,0.1,0.1) mm·mrad, while still preserving the overall product. [5,6,7] Thus, a transverse to longitudinal emittance exchanger would complete the manipulation by performing nx ⇔ nz , producing the final output emittance of ( nx , ny , nz ) = (0.1,0.1,10) mm·mrad. Current light source projects, such as Linac Coherent Light Source [8] and European X-FEL [9] compensate for the larger input emittances by running the driving electron beams at higher currents and greater energies; obviously emittance exchange manipulations would be beneficial.…”