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Description: We study a perturbation expansion for the solution of the nonlinear one-dimensional FEL equations. We show that in the case of a monochromatic wave, the radiated intensity satisfies a scaling relation that implies, for large distance z traveled along the undulator, a change in initial value of the radiation field corresponds to a translation in z (lethargy). Analytic continuation using Pade approximates yields accurate results for the radiation field early in saturation.
Date: January 7, 2004
Creator: KRINSKY, S.
Partner: UNT Libraries Government Documents Department

Time-resolved measurement of a self-amplified free-electron laser.

Description: We report on a time-resolved measurement of self-amplified spontaneous emission (SASE) free-electron laser (FEL) pulses. We observed that the spikes in the output of such free-electron laser pulses have an intrinsic positive chirp and the energy chirp in the electron bunch mapped directly into the FEL output. The measurement also provides rich information on the statistics of the FEL output.
Date: October 2, 2002
Creator: Li, Y.; Lewellen, J.; Huang, Z.; Sajaev, V. & Milton, S. V.
Partner: UNT Libraries Government Documents Department


Description: Two independently-driven laser accelerators were operated together in series for the first time in a proof-of-principle experiment to demonstrate staging. The ability to stage together these devices is important for eventually building practical laser-driven accelerators. The laser accelerators consisted of two identical inverse free electron lasers (IFEL), where the first IFEL served as a prebuncher, which created {approx}3-fs long microbunches that were accelerated by the second IFEL. Precise and stable control of the phasing between the microbunches and laser wave inside the second IFEL was demonstrated. The effects of over-modulation of the prebuncher were also investigated. In all cases there was good agreement with the model. Additional details of the microbunch characteristics could be inferred by using the model. Plans for demonstrating monoenergetic laser acceleration are also presented.
Date: June 18, 2001
Creator: Kimura, W. D.; Campbell, L. P.; DILLEY,C.E.; Gottschalk, S. C.; Quimby, D. C.; BABZIEN,M. BEN-ZVI,I. et al.
Partner: UNT Libraries Government Documents Department

Two-Color Experiments Combining the UV-Storage Ring Free Electron Laser and SA5 IR Beamline at Super-ACO

Description: This article reviews pump-probe experiments with a storage ring based free-electron laser pump, and synchrotron radiation as a broadband spectroscopic probe.
Date: July 19, 1999
Creator: Nahon, Laurent; Renault, Eric; Couprie, Marie-Emmanuelle; Nutarelli, Daniele; Garzella, David; Billardon, Michel et al.
Partner: UNT Libraries Government Documents Department

Inverse Cherenkov and inverse FEL accelerator experiments at the Brookhaven Accelerator Test Facility

Description: Status update on the ongoing inverse Cherenkov acceleration experiment and prospects to its 100 MeV short-term upgrade. The first report on 1 MeV electron acceleration with the 0.5 GW CO{sub 2} laser used in the inverse FEL scheme. (author). 22 refs., 8 figs., 1 tab.
Date: December 31, 1995
Creator: Pogorelsky, I.V.; vanSteenbergen, A. & Babzien, M.
Partner: UNT Libraries Government Documents Department


Description: Having produced 14 kW of average power at {approx}2 microns, JLAB has shifted its focus to the ultraviolet portion of the spectrum. This presentation will describe the JLab UV Demo FEL, present specifics of its driver ERL, and discuss the latest experimental results from FEL experiments and machine operations.
Date: July 1, 2012
Creator: Douglas, David; Evtushenko, Pavel; Gubeli, Joseph; Hernandez-Garcia, Carlos; Legg, Robert; Neil, George et al.
Partner: UNT Libraries Government Documents Department

Noninvariance of space/time-scale ranges under a Lorentztransformation and the implications for the study of relativisticinteractions

Description: The summary of this report is: (1) The range of scales {Lambda} of a system is not a Lorentz invariant and can vary greatly for some systems. (2) There exists an optimum frame which minimizes {Lambda}. (3) We demonstrated speedup of x1000 for PIC simulation of relativistic beam interacting with electron background. (4) It is not in contradiction with the conventional scientific wisdom that 'complexity' is an invariant. (5) We identified three domains of application (laser-plasma acceleration, e-cloud in HEP accelerators, free electron lasers) for which speedup ranging from 2 to 4 orders of magnitude were demonstrated on toy problems.
Date: June 1, 2007
Creator: Vay, Jean-Luc
Partner: UNT Libraries Government Documents Department

Free-Electron Lasers: Present Status and Future Prospects

Description: Free-electron lasers as scientific instruments are reviewed. The present status and future prospects are delineated with attention drawn to the size, complexity, availability, and performance capability of this new tool. The Free-Electron Laser (FEL) was proposed by John Madey in 1970 (1), although earlier work, relevant to the concept, had been performed by Motz (2) and by Phillips (3). Experimental demonstration was achieved by Madey, et. al. in 1975 and 1976 (4). Since that time, FELs of diverse configurations have been operated at several laboratories around the world. At present, FEL development is focused in two directions: in constructing reliable FELs for scientific research and in extending FEL capability to vacuum ultra-violet (VUV) and even shorter wavelengths. In this article we shall only very briefly review the principles of an FEL, putting emphasis on those aspects that limit performance, after which we shall discuss the applications, present status and future prospects of FELs. Much material that we wish to present is in the form of Tables, and they are an essential part of this article.
Date: May 1, 1990
Creator: Kim, K.-J. & Sessler, Andrew M.
Partner: UNT Libraries Government Documents Department

An Efficient Microwave Power Source: Free-electron Laser Afterburner

Description: A kind of microwave power source, called a free-electron laser afterburner (FEL afterburner) which consists of a free-electron laser buncher and a slow-wave output structure sharing a magnetic wiggler field with the buncher, is proposed. The buncher and the slow-wave structure can operate in either a travelling-wave state or a standing-wave state. In the buncher, the wiggler field together with the radiation field makes an electron beam bunched, and in the slow-wave structure the wiggler field keeps the beam bunched while the bunched beam interacts strongly with the slow-wave structure and so produces rf power. The bunching process comes from the free-electron laser mechanism and the generating process of rf power is in a slow-wave structure. A three-dimensional, time-dependent code is used to simulate a particular standing-wave FEL afterburner and it is shown that rf power of up to 1.57 GW can be obtained, at 17.12 GHz, from a l-kA, 5-MeV electron beam.
Date: March 4, 1993
Creator: Wang, C. & Sessler, Andrew M.
Partner: UNT Libraries Government Documents Department


Description: The spatial properties of the optical field and hence the performance of a free electron laser depend on the fact that the electron beam, which acts as both an amplifying and a refractive medium, is transversely nonuniform. Under certain circumstances, optical guiding may be realized, where the optical field is stably confined near the electron beam and amplified along the beam over many Rayleigh ranges. We show that the three-dimensional evolution of the optical field through the interaction region can be determined by a guided mode expansion before saturation. Optical guiding occurs when the fundamental growing mode becomes dominant. The guided mode expansion is made possible by implementing the biorthogonality of the eigenmodes of the coupled electron-beam-optical-wave system. The eigenmodes are found to be of vectorial form with three components; one specifies the guided optical mode and the other two describe the density and the energy modulations of the electron beam.
Date: March 1, 1989
Creator: Xie, M.; Deacon, D.A.G. & Madey, J.M.J.
Partner: UNT Libraries Government Documents Department

Isochronous Beamlines for Free Electron Lasers

Description: The transport systems required to feed a beam of highly relativistic electrons into a free electron laser have to satisfy very stringent requirements with respect to isochronicity and achromaticity. In addition, the line has to be tunable to match different operating modes of the free electron laser. Various beamlines emphasizing different aspects, such as quality of isochronicity and achromaticity, simplicity of the design, and space configurations are shown and compared. Solutions are presented having time resolution in the range of 2 to less than 0.5 picoseconds for one percent of energy spread.
Date: July 1, 1990
Creator: Berz, M.
Partner: UNT Libraries Government Documents Department

Limits to Electron Beam Emittance from Stochastic Coulomb Interactions

Description: Dense electron beams can now be generated on an ultrafast timescale using laser driven photo-cathodes and these are used for a range of applications from ultrafast electron defraction to free electron lasers. Here we determine a lower bound to the emittance of an electron beam limited by fundamental stochastic Coulomb interactions.
Date: August 22, 2008
Creator: Coleman-Smith, Christopher; Padmore, Howard A. & Wan, Weishi
Partner: UNT Libraries Government Documents Department