Coherence properties of the radiation from SASE FEL

Saldin, E.L.; Schneidmiller, Evgeni; Yurkov, M.V.

doi:10.1016/b978-0-444-51417-2.50031-6

Cited by 39 publications

(63 citation statements)

References 12 publications

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“…Numerical and theoretical investigations of high-brightness electron bunch compression reveal a microbunching instability driven by coherent synchrotron radiation (CSR) that can significantly degrade the beam quality [3][4][5][6]. Recently, Saldin et al pointed out that the longitudinal space charge (LSC) field can be the main effect driving the microbunching instability in the TESLA Test Facility (TTF) (phase 2) linac [7]. In addition, significant LSC-induced energy modulation in the deep ultraviolet FEL (DUV-FEL) linac has been experimentally characterized using an rf zero-phasing method [8].…”

Section: Introductionmentioning

confidence: 99%

Suppression of microbunching instability in the linac coherent light source

Huang

Borland

Emma

et al. 2004

Phys. Rev. ST Accel. Beams

227

235

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A microbunching instability driven by longitudinal space charge, coherent synchrotron radiation, and linac wakefields is studied for the linac coherent light source (LCLS) accelerator system. Since the uncorrelated (local) energy spread of electron beams generated from a photocathode rf gun is very small, the microbunching gain may be large enough to significantly amplify rf-gun generated modulations or even shot-noise fluctuations of the electron beam. The uncorrelated energy spread can be increased by an order of magnitude to provide strong Landau damping against the instability without degrading the free-electron laser performance. We study different damping options in the LCLS and discuss an effective laser heater to minimize the impact of the instability on the quality of the electron beam.

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Section: Introductionmentioning

confidence: 99%

Suppression of microbunching instability in the linac coherent light source

Huang

Borland

Emma

et al. 2004

Phys. Rev. ST Accel. Beams

227

235

View full text Add to dashboard Cite

show abstract

“…Subsequently, it was proposed that the longitudinal space charge (LSC) fields might be the main effect in driving the microbunching instability at FIR wavelengths in a linac [8,9]. We now propose that the LSC-CSR microbunching instability in the linac at 300-A peak current had effected the observed spatially localized SASE-induced microbunching and related SASE effects in the visible light regime in those 2001 experiments at APS.…”

Section: Introductionmentioning

confidence: 95%

Coherent optical transition radiation and self-amplified spontaneous emission generated by chicane-compressed electron beams

Lumpkin

Dejus

Sereno

2009

Phys. Rev. ST Accel. Beams

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Observations of strongly enhanced optical transition radiation (OTR) following significant bunch compression of photoinjector beams by a chicane have been reported during the commissioning of the Linac Coherent Light Source accelerator and recently at the Advanced Photon Source (APS) linac. These localized transverse spatial features involve signal enhancements of nearly a factor of 10 and 100 in the APS case at the 150-MeV and 375-MeV OTR stations, respectively. They are consistent with a coherent process seeded by noise and may be evidence of a longitudinal space charge microbunching instability which leads to coherent OTR emissions. Additionally, we suggest that localized transverse structure in the previous self-amplified spontaneous emission (SASE) free-electron laser (FEL) data at APS in the visible regime as reported at FEL02 may be attributed to such beam structure entering the FEL undulators and inducing the SASE startup at those ''prebunched'' structures. Separate beam structures 120 microns apart in x and 2.9 nm apart in wavelength were reported. The details of these observations and operational parameters will be presented.

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“…A laser with power P L will generate a modulation amplitude of 18) with P 0 = 8.7 GW and Bessel factor…”

Section: Example Radiation Sources From Ssmb 741 Euv Sourcementioning

confidence: 99%

“…While shot noise drives Self-Amplified Spontaneous Emission (SASE) Free Electron Lasers (FELs), the same density fluctuations may adversely affect FEL operation. For example, the microbunching instability, thought to originate from shot noise, can incapacitate diagnostics and degrade FEL performance [18,20,1,44,45,46,47]. Shot noise also competes with external modulations in the operation of seeded FELs [12,13].…”

Section: Introductionmentioning

confidence: 99%

“…In a high-brightness linear accelerator, as used for a high-gain free electron laser (FEL), impedance effects along the accelerator can drive a periodic microbunching instability that degrades the electron beam qualities [6,18,19,20,21,22,23,24]. Longitudinal space charge (LSC) forces may dominate microbunching gain at wavelengths shorter than the electron bunch [21,22,23,24].…”

Section: Introductionmentioning

confidence: 99%

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