Design of an x-ray free electron laser undulator
An undulator designed to be used for an x-ray free electron laser has to meet a set of stringent requirements. With no optical cavity, an x-ray FeL operates in the single pass Self Amplified Spontaneous Emission (SASE) mode; an electron macropulse is microbunched by an undulator and the radiation it creates. The microbunched pulse emits spontaneous radiation and coherent FEL radiation, whose power may reach saturation in a sufficiently long and perfect undulator. The pulse must have low emittance and high current, and its trajectory in the undulator must keep the radiation and the pulse together with a very high degree of overlap. The authors shall consider the case of the Linear Coherent Light Source (LCLS) FEL project at SLAC, which is intended to create 1.5 {angstrom} x-rays using an electron beam with 15 GeV energy, 1.5{pi} mm-mrad normalized emittance, 3,400 A peak current, and 280 fsec FWHM bunch duration. They find that this 65 {micro}m rms diameter beam must overlap its radiation with a walk/off of no more than 5 {micro}m for efficient gain. This places severe limitations on the magnetic field errors and other mechanical tolerances. The following is a discussion of the undulator design, specifications, alignment, engineering, and beam position monitoring they plan to implement for the LCLS X-ray FEL.
- Research Organization:
- Stanford Univ., Stanford Linear Accelerator Center, CA (US)
- Sponsoring Organization:
- USDOE Office of Energy Research, Washington, DC (US)
- DOE Contract Number:
- AC03-76SF00515
- OSTI ID:
- 663315
- Report Number(s):
- SLAC-PUB-7651; CONF-9706157-; ON: DE98059141; TRN: US200305%%912
- Resource Relation:
- Conference: SRI '97: 10. U.S. national conference on synchrotron radiation instrumentation, Ithaca, NY (US), 06/17/1997--06/20/1997; Other Information: Supercedes report DE98059141; PBD: Sep 1997; PBD: 1 Sep 1997
- Country of Publication:
- United States
- Language:
- English
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Design of an x-ray free electron laser undulator
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