Design of an x-ray free electron laser undulator

Journal Article · Tue Jul 01 04:00:00 EDT 1997 · AIP Conference Proceedings

DOI:https://doi.org/10.1063/1.54589· OSTI ID:21179531

Carr, Roger ^[1]

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1. Stanford Synchrotron Radiation Laboratory, Stanford Linear Accelerator Center, Stanford, California 94309 (United States)

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. We shall consider the case of the Linear Coherent Light Source (LCLS) FEL project at SLAC, which is intended to create 1.5 A x-rays using an electron beam with 15 GeV energy, 1.5{pi} mm-mrad normalized emittance, 3400 A peak current, and 280 fsec FWHM bunch duration. We find that this 65 {mu}m rms diameter beam must overlap its radiation with a walkoff of no more than 5 {mu}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 we plan to implement for the LCLS X-ray FEL.

• OSTI ID: 21179531
• Journal Information: AIP Conference Proceedings, Journal Name: AIP Conference Proceedings Journal Issue: 1 Vol. 417; ISSN 0094-243X; ISSN APCPCS
• Country of Publication: United States
• Language: English

Related Subjects

43 PARTICLE ACCELERATORS
ALIGNMENT
BEAM BUNCHING
BEAM EMITTANCE
BEAM MONITORING
BEAM POSITION
DESIGN
ELECTRON BEAMS
ELECTRONS
FREE ELECTRON LASERS
GAIN
GEV RANGE
LIGHT SOURCES
MAGNETIC FIELDS
PULSES
STANFORD LINEAR ACCELERATOR CENTER
WIGGLER MAGNETS
X RADIATION