Transverse-to-longitudinal emittance exchange to improve performance of high-gain free-electron lasers.
The ability to generate small transverse emittance is perhaps the main limiting factor for the performance of high-gain x-ray free-electron lasers (FELs). Noting that beams from an rf photocathode gun can have energy spread much smaller than required for efficient FEL interaction, we present a method to produce normalized transverse emittance at or below about 0.1 {micro}m, which will lead to a significantly shorter length undulator as well as a lower electron beam energy for an x-ray FEL project. The beam manipulation consists of producing an unequal partition of the initially equal emittances into two dissimilar emittances by a flat-beam technique and exchanging the larger transverse emittance with a smaller longitudinal emittance. We study various issues involved in the manipulation. In particular, a new emittance exchange optics we found enables an exact emittance exchange necessary for this scheme.
- Research Organization:
- Argonne National Lab. (ANL), Argonne, IL (United States)
- Sponsoring Organization:
- USDOE Office of Science (SC); OUS
- DOE Contract Number:
- DE-AC02-06CH11357
- OSTI ID:
- 935632
- Report Number(s):
- ANL/ASD/JA-57080; TRN: US0804597
- Journal Information:
- Phys. Rev. ST Accel Beams, Vol. 9, Issue Oct. 2006; ISSN 1098-4402
- Country of Publication:
- United States
- Language:
- ENGLISH
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