Two-Bunch Self-Seeding for Narrow-Bandwidth Hard X-Ray Free-Electron Lasers
It is well-known that seeding can be used to produce narrow-bandwidth and fully-coherent x- ray free-electron lasers. Self-seeding, which uses an extra undulator to generate the seed pulse, is perhaps one of the most promising methods to accomplish this. In the hard x-ray regime with high- energy electrons, this method requires a large magnetic chicane to match the path length delay of the x-ray monochromator that selects a narrow bandwidth of radiation. Such a chicane not only takes large footprint to build, but also may degrade the electron beam qualities through incoherent and coherent synchrotron radiation. In this paper, we present an alternative two-bunch self-seeding scheme. The two bunches are precisely separated to match the x-ray delay of the monochromator and eliminate the need for a long, complex magnetic chicane. The spectrally filtered SASE x-ray pulse produced by the first bunch is combined with the second electron bunch at the entrance of the second undulator and then amplified to the saturation level. We present start-to-end simulation results based on the LCLS hard x-ray FEL and show that this method can produce a nearly fully coherent x-ray pulse at a few GW power level.
- Research Organization:
- SLAC National Accelerator Lab., Menlo Park, CA (United States)
- Sponsoring Organization:
- USDOE
- DOE Contract Number:
- AC02-76SF00515
- OSTI ID:
- 981363
- Report Number(s):
- SLAC-PUB-14021; TRN: US1003912
- Journal Information:
- Submitted to Physical Review Special Topics - Accelerators and Beams, Vol. 13, Issue 6; ISSN 1098-4402
- Country of Publication:
- United States
- Language:
- English
Similar Records
X-ray absorption spectroscopy using a self-seeded soft X-ray free-electron laser
The seed energy fluctuation of hard X-ray self-seeding free electron laser