Accelerator Physics Challenges of X-Ray FEL SASE Sources
A great deal of international interest has recently focused on the design and construction of free-electron lasers (FEL) operating in the x-ray region ({approx}1 {angstrom}). At present, a linac-based machine utilizing the principle of self-amplified spontaneous emission (SASE) appears to be the most promising approach. This new class of FEL achieves lasing in a single pass of a high brightness electron beam through a long undulator. The requirements on electron beam quality become more demanding as the FEL radiation wavelength decreases, with the 1-{angstrom} goal still 3-orders of magnitude below the shortest wavelength operational SASE FEL (TTF-FEL at DESY [1]). The subpicosecond bunch length drives damaging effects such as coherent synchrotron radiation, and undulator vacuum chamber wakefields. Unlike linear colliders, beam brightness needs to be maintained only over a small ''slice'' of the bunch length, so the concepts of bunch integrated emittance and energy spread are less relevant than their high-frequency (or ''time-sliced'') counterparts, also adding a challenge to phase space diagnostics. Some of the challenges associated with the generation, preservation, measurement, and stability of high brightness FEL electron beams are discussed here.
- Research Organization:
- SLAC National Accelerator Lab., Menlo Park, CA (United States)
- Sponsoring Organization:
- USDOE Office of Energy Research (ER) (US)
- DOE Contract Number:
- AC03-76SF00515
- OSTI ID:
- 799090
- Report Number(s):
- SLAC-PUB-9243; TRN: US0204435
- Resource Relation:
- Other Information: PBD: 30 May 2002
- Country of Publication:
- United States
- Language:
- English
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