Laser-Seeded Free-Electron Lasers at the NSLS

Murphy, J.B.; Wang, Xijie

doi:10.1080/08940880701863947

Cited by 11 publications

(6 citation statements)

References 19 publications

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“…We conducted the experiments described here at the Source Development Laboratory (SDL) of the National Synchrotron Light Source (NSLS), Brookhaven National Laboratory. The SDL is a laser linac facility featuring a high-brightness electron source, a 4-magnet chicane bunch compressor, an S-band SLAC type traveling-wave linac, and a Ti:sapphire laser system [16]. The 100 MeV high-brightness electron beam passes through the NISUS undulator [17], a 10-m-long planar undulator consisting of 16 sections, with a period of 3.89 cm.…”

Section: Methodsmentioning

confidence: 99%

Experimental demonstration of a slippage-dominant free-electron laser amplifier

et al. 2012

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We report the first experimental demonstration of a slippage-dominant free-electron laser (FEL) amplifier using a 140-fs full width at half maximum broadband seed laser pulse. The evolution of the longitudinal phase space of a laser seeded FEL amplifier in the slippage-dominant regime was experimentally characterized. We observed, for the first time, that the pulse duration of the FEL is primarily determined by the slippage between the seed laser and the electron beam. With a ± 1% variation in the electron-beam energy, we demonstrated reasonably good longitudinal coherence and a ± 2% spectral tuning range. The experimentally observed temporal and spectral evolution of the slippage-dominant FEL was verified by the numerical simulations.

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Section: Methodsmentioning

confidence: 99%

Experimental demonstration of a slippage-dominant free-electron laser amplifier

et al. 2012

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“…In the SDL [30], the electron beam generated in the photocathode rf gun is first accelerated to about 70 MeV, utilizing two linac tanks of the SLAC type. It is then compressed in the bunch compressor (BC) consisting of the linac section, which introduces a correlated energy spread (chirp), and a four-bend chicane, which produces relevant momentum compaction.…”

Section: A Sdl Facilitymentioning

confidence: 99%

Initial source of microbunching instability studies in a free electron laser injector

Seletskiy

Hidaka

Murphy

et al. 2011

Phys. Rev. ST Accel. Beams

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We present the first experimental studies of the initial source of electron beam microbunching instability in a free electron laser (FEL) injector. By utilizing for the studies a transform-limited laser pulse at the photocathode, we eliminated laser-induced microbunching at the National Synchrotron Light Source Source Development Laboratory (SDL). The detailed measurements of the resulting electron beam led us to conclude that, at SDL, microbunching arising from shot noise is not amplified to any significant level, thereby allowing us to set an upper limit on the initial modulation depth of microbunching arising from shot noise. Our analysis demonstrated that the only significant source of microbunching instability under normal operational conditions at SDL is the longitudinal modulation of the photocathode laser pulse. Our work shows that assuring a longitudinally smoothed photocathode laser pulse allows mitigating microbunching instability at a typical FEL injector with a moderate microbunching gain.

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“…A potential application of this particular LSCA scheme is for controlling waveforms and enhancing the spectral content of linac-based sources of coherent terahertz radiation. The linear accelerators, commonly used as injectors, for short wavelength free electron lasers (FELs) [1,2] utilize bunch compressors (BC) [2,3] for producing electron bunches having both high charge and subpicosecond length. A typical BC reduces the lengths of individual bunches in a bunched electron beam by inducing a welldefined correlation between the energy and longitudinal position of an electron in the bunch (energy chirp).…”

mentioning

confidence: 99%

“…Preliminary results of our work were reported in [15]. At the SDL [2] an electron bunch generated in the photocathode RF gun is accelerated to 70 MeV, utilizing two SLAC type traveling-wave linear accelerator sections. The RF phase for one section is set for off-crest acceleration to produce the energy chirp.…”

mentioning

confidence: 99%

Seeding, Controlling, and Benefiting from the Microbunching Instability

et al. 2013

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Advanced light sources using relativistic electrons rely on coherent emission from high-density (compressed) beams. These beams, typically produced by photoinjected linear accelerators, can suffer from uncontrolled microbunching instabilities that are difficult to manage, since a complete understanding of their growth due to space charge and other wakefields is lacking. Here we present the first systematic measurements of microbunching instability using electron beams premodulated in a controlled fashion. By comparing beams having various modulation depths and wavelengths with unmodulated beams, we are able to benchmark, for the first time, the analytical calculations for the microbunching instability. In addition, our results give a proof of principle demonstration of a longitudinal space charge amplifier (LSCA), where a specific beam density pattern develops and grows. A potential application of this particular LSCA scheme is for controlling waveforms and enhancing the spectral content of linac-based sources of coherent terahertz radiation.

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Laser-Seeded Free-Electron Lasers at the NSLS

Cited by 11 publications

References 19 publications

Experimental demonstration of a slippage-dominant free-electron laser amplifier

Experimental demonstration of a slippage-dominant free-electron laser amplifier

Initial source of microbunching instability studies in a free electron laser injector

Seeding, Controlling, and Benefiting from the Microbunching Instability

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