Laser pulse shaping for generating uniform three-dimensional ellipsoidal electron beams

Li, Yuelin; Chemerisov, Sergey; Lewellen, John W.

doi:10.1103/physrevstab.12.020702

Cited by 31 publications

(26 citation statements)

References 47 publications

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“…The latter equation hints that the blow-out regime is generally unfavorable to emittance when operating with high-charge bunches produced in low-peak-field rf guns. For this reason, directly shaping the laser profile to follow an ellipsoidal distribution would be more effective when an improvement of the transverse emittance is desired [5,46] and for our range of bunch charges.…”

Section: Transverse Emittancementioning

confidence: 99%

Formation and acceleration of uniformly filled ellipsoidal electron bunches obtained via space-charge-driven expansion from a cesium-telluride photocathode

Piot

Sun

Maxwell

et al. 2013

Phys. Rev. ST Accel. Beams

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We report the experimental generation, acceleration, and characterization of a uniformly filled electron bunch obtained via space-charge-driven expansion (often referred to as ''blow-out regime'') in an L-band (1.3-GHz) radiofrequency photoinjector. The beam is photoemitted from a cesium-telluride semiconductor photocathode using a short (< 200 fs) ultraviolet laser pulse. The produced electron bunches are characterized with conventional diagnostics and the signatures of their ellipsoidal character are observed. We especially demonstrate the production of ellipsoidal bunches with charges up to $0:5 nC corresponding to a $20-fold increase compared to previous experiments with metallic photocathodes.

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Section: Transverse Emittancementioning

confidence: 99%

Formation and acceleration of uniformly filled ellipsoidal electron bunches obtained via space-charge-driven expansion from a cesium-telluride photocathode

Piot

Sun

Maxwell

et al. 2013

Phys. Rev. ST Accel. Beams

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“…The drive laser strikes the photocathode surface to emit electrons. The temporal and transverse shape of the laser pulse, together with the quantum efficiency (QE) of the photocathode surface, determines the temporal and transverse distribution of the electron beam upon emission, which has a significant impact on beam brightness and FEL performance [5][6][7][8][9][10]. The temporal distribution can be manipulated with techniques such as polarization based pulse stacking with birefringent crystals [11], acousto-optic modulators [12,13] or spatial modulators at a dispersion region [14].…”

Section: Introductionmentioning

confidence: 99%

Ultraviolet laser transverse profile shaping for improving x-ray free electron laser performance

Alverson

Bohler

et al. 2017

Phys. Rev. Accel. Beams

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The photocathode rf gun is one of the most critical components in x-ray free electron lasers. The drive laser strikes the photocathode surface, which emits electrons with properties that depend on the shape of the drive laser. Most free electron lasers use photocathodes with work function in the ultraviolet, a wavelength where direct laser manipulation becomes challenging. In this paper, we present a novel application of a digital micromirror device (DMD) for the 253 nm drive laser at the Linear Coherent Light Source. Laser profile shaping is accomplished through an iterative algorithm that takes into account shaping error and efficiency. Next, we use laser shaping to control the X-ray laser output via an online optimizer, which shows improvement in FEL pulse energy. Lastly, as a preparation for electron beam shaping, we use the DMD to measure the photocathode quantum efficiency across cathode surface with an averaged laser rms spot size of 59 μm. Our experiments demonstrate promising outlook of using DMD to shape ultraviolet lasers for photocathode rf guns with various applications.

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“…• Illuminate the cathode with short laser pulse (duration < 100 fs), called pancake-like distribution, and use the longitudinal space charge driven expansion to create a nearly ideal uniformly filled ellipsoidal distribution [39,50,51]; • Illuminate the cathode with long (≈few ps) and skinny (<100 µm spot size) laser pulse, also called cigar-like, and use the transverse space charge to drive the beam expansion [52].…”

Section: Non Linearity In the Longitudinal Phase Space Distributionmentioning

confidence: 99%

Conceptual and Technical Design Aspects of Accelerators for External Injection in LWFA

et al. 2018

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Laser driven Wake-Field Acceleration (LWFA) has proven its capability of accelerating electron bunches (e-bunches) to up to 4 GeV energy in a single stage while reaching gradients up to hundreds of GV/m. Because of the short period of the accelerating field (typically ranging from 100 fs to 1 ps duration) and the requirement of extremely small beam size (typically smaller than 1 µm) to match the channel, e-bunches can reach extremely high densities. They can be either extracted directly from the plasma or externally injected. The study of the external injection is interesting for two main reasons. On the one hand this method allows better control of the quality of the input beam and on the other hand it is in general necessary when a staged approach of the accelerator is considered. The interest in producing, characterizing and transporting high brightness ultra-short e-bunches has grown together with the interest in LWFA and other novel high-gradient acceleration techniques. In this paper we will review the principal techniques for producing and shaping ultra-short electron bunches with the example of the SINBAD-ARES (Accelerator Research Experiment at SINBAD) linac at the Deutsches Elektronen-Synchrotron (DESY). Our goal is to show how the design of the SINBAD-ARES linac satisfies the requirements for generating high brightness LWFA probes. In the last part of the paper we shall also comment on the technical challenges for electron control and characterization.

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Laser pulse shaping for generating uniform three-dimensional ellipsoidal electron beams

Cited by 31 publications

References 47 publications

Formation and acceleration of uniformly filled ellipsoidal electron bunches obtained via space-charge-driven expansion from a cesium-telluride photocathode

Formation and acceleration of uniformly filled ellipsoidal electron bunches obtained via space-charge-driven expansion from a cesium-telluride photocathode

Ultraviolet laser transverse profile shaping for improving x-ray free electron laser performance

Conceptual and Technical Design Aspects of Accelerators for External Injection in LWFA

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