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FEL 1993 15th

Name: FEL 1993 15th

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Date: 1993-01-01

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Created at: Fri Jul 27 23:53:34 -0700 2007

Updated at: Fri Jul 27 23:53:34 -0700 2007

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5 papers from the conference:

title: Slippage, noise and superradiant effects in the UCLA FEL experiment
format: conference proceeding
conference: FEL 1993 15th
year: 1994
5 authors: R. Bonifacio | P. Pierini | C. Pellegrini | J.B. Rosenzweig | G. Travish
abstract: We present the results of numerical calculations of the effects of noise, slippage and superradiance in the UCLA infrared (IR) free electron laser (FEL). The experiment, which uses a high brightness electron beam produced by a photocathode RF gun and a 1.5 cm period planar undulator, compares the FEL evolution starting from noise to that starting from an input signal. Numerical studies indicate that we can observe saturation, optical guiding effects and a superradiant spike.
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title: A Study of Linewidth, Noise and Fluctuations in a FEL Operating in SASE
format: conference proceeding
conference: FEL 1993 15th
year: 1994
5 authors: Bonifacio, R. | De Salvo, L. | P. Pierini | Piovella, N. | C. Pellegrini
abstract: We study the evolution of the FEL radiation intensity and spectrum starting from noise in the electron beam longitudinal distribution. Due to the slippage both the time and frequency structure of the emitted radiation pulse show a very different behavior when the bunch length is much longer than or of the order of the cooperation length l(c). The occurrence of superradiant spikes is discussed. We present analytical and numerical results.
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title: The SLAC soft X-ray high power FEL
format: conference proceeding
conference: FEL 1993 15th
year: 1994
23 authors: C. Pellegrini | J.B. Rosenzweig | G. Travish | K. Bane | R. Boyce | G. Loew | P. Morton | H. D. Nuhn | J. Paterson | P. Pianetta | T. Raubenheimer | J. Seeman | R. Tatchyn | V. Vylet | H. Winick | K. Halbach | K. J. Kim | M. Xie | D. Prosnitz | E. T. Scharlemann | R. Bonifacio | L. De Salvo | P. Pierini
abstract: We discuss the design and performance of a 2 to 4 nm FEL operating in self-amplified spontaneous emission (SASE), using a photoinjector to produce the electron beam, and the SLAC linac to accelerate it to an energy of about 7 GeV. Longitudinal bunch compression is used to increase the peak current to 2.5 kA, while reducing the bunch length to about 40 mu m. The FEL field gain length is about 6 m, and the saturation length is about 60 m. The saturated output power is about 10 GW, corresponding to about 10/sup 14/ photons in a single pulse in a bandwidth of about 0.1%, with a pulse duration of 0.16 ps. Length compression, emittance control, phase stability, FEL design criteria, and parameter tolerances are discussed. (15 References).
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title: Initial measurements of the UCLA RF photoinjector
format: conference proceeding
conference: FEL 1993 15th
year: 1994
2 authors: S. Hartman | M. Hogan
abstract: An RF photocathode gun which, along with a compact linac, forms the injection system for a planned 10 mm free-electron laser amplifier experiment, has been commissioned in the Particle Beam Physics Laboratory at UCLA. This high-gradient gun, based on the Brookhaven design, has emitted several picosecond, [right angle bracket]100 A electron beams of up to 4 MeV in energy. These beams have been characterized by a variety of diagnostics. The quantum efficiency of the copper cathode used has been measured at normal incidence, and at 70 degrees incidence, where the polarization dependence was also examined. Limits on laser intensity due to surface damage, and to longitudinal space charge suppression of photoemission have been explored. The energy and energy spread of the beam were characterized using a dipole spectrometer, while the time structure was examined using a picosecond resolution streak camera. Both energy spread and pulse length were found to be adversely affected by longitundinal space charge forces. The emittance of the beam was measured using the pepper pot Technique, and its dependence on space charge and rf phase were found. The impact of these results on imporving the design and operation of high brightness photoinjectors is discussed, in particular with respect to SASE FEL amplifiers such as the UCLA 10mm FEL, and the proposed SLAC X-ray FEL.
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title: A millimeter wave FEL driven by a photocathode RF linac
format: conference proceeding
conference: FEL 1993 15th
year: 1994
11 authors: R. Zhang | C. Pellegrini | J.B. Rosenzweig | G. LeSage | F. Hartemann | D. McDermott | C. Joshi | N. Luhmann | P. Pierini | de Salvo, L. | Bonifacio, R.
abstract: We present the design of a millimeter wave FEL based on the UCLA photocathode RF linac. The linac energy can be varied between 5 and 18 MeV. The electron pulse duration is 2 ps FWHM, with a peak current exceeding 150 A. The FEL is designed to operate in the high-gain Compton regime, controlling the slippage with the propagating radiation in a waveguide. The design permits the exploration of the basic FEL physics in this regime, including the exploration of saturation and lethargy in the superradiant and steady state regime. (15 References).
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