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S. Weathersby

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Last Name: Weathersby

Full Name: S. Weathersby

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2 papers
title: Single-Shot Coherent Diffraction Imaging of Microbunched Relativistic Electron Beams for Free-Electron Laser Applications
format: journal article
publisher: Physical Review Letters
year: March 2013
10 authors: A. Marinelli | M. Dunning | S. Weathersby | E. Hemsing | D. Xiang | G. Andonian | F.H. O'Shea | Jianwei Miao | C. Hast | J. B. Rosenzweig
abstract: With the advent of coherent x rays provided by the x-ray free-electron laser (FEL), strong interest has been kindled in sophisticated diffraction imaging techniques. In this Letter, we exploit such techniques for the diagnosis of the density distribution of the intense electron beams typically utilized in an x-ray FEL itself. We have implemented this method by analyzing the far-field coherent transition radiation emitted by an inverse-FEL microbunched electron beam. This analysis utilizes an oversampling phase retrieval method on the transition radiation angular spectrum to reconstruct the transverse spatial distribution of the electron beam. This application of diffraction imaging represents a significant advance in electron beam physics, having critical applications to the diagnosis of high-brightness beams, as well as the collective microbunching instabilities afflicting these systems.

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title: Generation of Coherent Broadband Photon Pulses with a Cascaded Longitudinal Space-Charge Amplifier
format: journal article
publisher: Physical Review Letters
year: 2013
9 authors: A. Marinelli | E. Hemsing | M. Dunning | D. Xiang | S. Weathersby | F. O'Shea | I. Gadjev | C. Hast | J.B. Rosenzweig
abstract: The longitudinal space-charge amplifier has been recently proposed by Schneidmiller and Yurkov as an alternative to the free-electron laser instability for the generation of intense broadband radiation pulses [Phys. Rev. ST Accel. Beams 13, 110701 (2010)]. In this Letter, we report on the experimental demonstration of a cascaded longitudinal space-charge amplifier at optical wavelengths. Although seeded by electron beam shot noise, the strong compression of the electron beam along the three amplification stages leads to emission of coherent undulator radiation pulses exhibiting a single spectral spike and a single transverse mode. The on-axis gain is estimated to exceed 4 orders of magnitude with respect to spontaneous emission.

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