Reversible electron beam heating for suppression of microbunching instabilities at free-electron lasers

Behrens, C.; Huang, Zhirong; Xiang, Dao

doi:10.1103/physrevstab.15.022802

Cited by 24 publications

(18 citation statements)

References 28 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…One 11-cell deflector is mainly used to increase the beam slice energy spread [25,40], and the other 27-cell deflector is used for measuring the temporal profile of electron beams. These two deflectors are shown in Fig.…”

Section: Nlcta X-band Deflectorsmentioning

confidence: 99%

Design and application of multimegawattX-band deflectors for femtosecond electron beam diagnostics

Dolgashev

Bowden

Ding

et al. 2014

Phys. Rev. ST Accel. Beams

Self Cite

View full text Add to dashboard Cite

Performance of the x-ray free electron laser Linac Coherent Light Source (LCLS) and the Facility for Advanced Accelerator Experimental Tests (FACET) is determined by the properties of their extremely short electron bunches. Multi-GeV electron bunches in both LCLS and FACET are less than 100 fs long. Optimization of beam properties and understanding of free-electron laser operation require electron beam diagnostics with time resolution of about 10 fs. We designed, built and commissioned a set of high frequency X-band deflectors which can measure the beam longitudinal space charge distribution and slice energy spread to better than 10 fs resolution at full LCLS energy (14 GeV), and with 70 fs resolution at full FACET energy (20 GeV). Use of high frequency and high gradient in these devices allows them to reach unprecedented performance. We report on the physics motivation, design considerations, operational configuration, cold tests, and typical results of the X-band deflector systems currently in use at SLAC.

show abstract

Section: Nlcta X-band Deflectorsmentioning

confidence: 99%

Design and application of multimegawattX-band deflectors for femtosecond electron beam diagnostics

Dolgashev

Bowden

Ding

et al. 2014

Phys. Rev. ST Accel. Beams

Self Cite

View full text Add to dashboard Cite

show abstract

“…The microbunching instability can be suppressed through various techniques that rely on electron beam manipulation [7,[10][11][12][13]. The most popular technique used in many facilities is a laser heater, which employs a polarized laser pulse in a short undulator located in the middle of a chicane to increase the uncorrelated energy spread of the electron beam [10].…”

Section: Introductionmentioning

confidence: 99%

Suppression of microbunching instability via a transverse gradient undulator

et al. 2015

View full text Add to dashboard Cite

The microbunching instability in the linear accelerator (linac) of a free-electron laser facility has always been a problem that degrades the electron beam quality. In this paper, a quite simple and inexpensive technique is proposed to smooth the electron beam current profile to suppress the instability. By directly adding a short undulator with a transverse gradient field right after the injector to couple the transverse spread into the longitudinal direction, additional density mixing in the electron beam is introduced to smooth the current profile, which results in the reduction of the gain of the microbunching instability. The magnitude of the density mixing can be easily controlled by varying the strength of the undulator magnetic field. Theoretical analysis and numerical simulations demonstrate the capability of the proposed technique in the accelerator of an x-ray freeelectron laser.

show abstract

“…Microbunching instabilities associated with longitudinal electron bunch compression can be mitigated by introducing additional uncorrelated energy spread [21][22][23] as successfully demonstrated by the operation of the laser heater system at the LCLS [9]. However, the microbunching gain suppression is not necessarily perfect, and the corresponding remaining small but existing level of COTR still hampers electron beam profile diagnostics using standard imaging screens (e.g., Ref.…”

Section: Introductionmentioning

confidence: 99%

Electron beam profile imaging in the presence of coherent optical radiation effects

Behrens

Gerth

Kube

et al. 2012

Phys. Rev. ST Accel. Beams

Self Cite

View full text Add to dashboard Cite

High-brightness electron beams with low energy spread at existing and future x-ray free-electron lasers are affected by various collective beam self-interactions and microbunching instabilities. The corresponding coherent optical radiation effects, e.g., coherent optical transition radiation, impede electron beam profile imaging and become a serious issue for all kinds of electron beam diagnostics using imaging screens. Furthermore, coherent optical radiation effects can also be related to intrinsically ultrashort electron bunches or the existence of ultrashort spikes inside the electron bunches. In this paper, we discuss methods to suppress coherent optical radiation effects both by electron beam profile imaging in dispersive beam lines and by using scintillation imaging screens in combination with separation techniques. The suppression of coherent optical emission in dispersive beam lines is shown by analytical calculations, numerical simulations, and measurements. Transverse and longitudinal electron beam profile measurements in the presence of coherent optical radiation effects in nondispersive beam lines are demonstrated by applying a temporal separation technique.

show abstract

Reversible electron beam heating for suppression of microbunching instabilities at free-electron lasers

Cited by 24 publications

References 28 publications

Design and application of multimegawattX-band deflectors for femtosecond electron beam diagnostics

Design and application of multimegawattX-band deflectors for femtosecond electron beam diagnostics

Suppression of microbunching instability via a transverse gradient undulator

Electron beam profile imaging in the presence of coherent optical radiation effects

Contact Info

Product

Resources

About