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Three-dimensional free electron laser dispersion relation including betatron oscillations

Description: We have developed a 3-D FEL theory based upon the Maxwell-Vlasov equations including the effects of the energy spread and emittance of the electron beam, and of betatron oscillations. The radiation field is expressed in terms of the Green's function of the inhomogeneous wave equation and the distribution function of the electron beam. The distribution function is expanded in terms of a set of orthogonal functions determined by the unperturbed particle distribution. The coupled Maxwell-Vlasov eq… more
Date: August 1, 1991
Creator: Chin, Y. H.; Kim, K. J. & Xie, M.
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Partner: UNT Libraries Government Documents Department
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Three-dimensional simulation of a hole-coupled FEL oscillator

Description: The performance of a two-mirror resonator with holes for out-coupling has been examined in a previous study in which the FEL gain was neglected, but the geometrical effect of the wiggler aperture was included in the optical calculation. The phenomenon of mode degeneracy was found to occur, that has serious implications for the stability of performance when the FEL gain is included. We have developed a FEL oscillator code based on TDA'', a three-dimensional FEL amplifier code, to study the mode … more
Date: August 1, 1991
Creator: Krishnagopal, S.; Xie, M.; Kim, K. J. & Sessler, A.
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Partner: UNT Libraries Government Documents Department
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Photon storage cavities

Description: A general analysis is presented of a photon storage cavity, coupled to free-electron laser (FEL) cavity. It is shown that if the coupling between the FEL cavity and the storage cavity is unidirectional (for example, a ring resonator storage cavity) then storage is possible, but that if the coupling is bi-directional then storage is not possible. Parameters are presented for an infra-red FEL storage cavity giving an order of magnitude increase in the instantaneous photon power within the storage… more
Date: August 1, 1991
Creator: Kim, K. J. & Sessler, A. M.
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Partner: UNT Libraries Government Documents Department
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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 div… more
Date: May 1, 1990
Creator: Kim, K. J. & Sessler, Andrew M.
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Partner: UNT Libraries Government Documents Department
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Generation of Femtosecond X-Rays by 90 degrees Compton Scattering

Description: We propose Compton scattering of a short pulse visible laser beam by a low energy (but relativistic) electron beam at a right angle for generation of femtosecond x-rays. Simple analysis to determine the qualitative and quantitative characteristics of the x-ray pulse is presented.
Date: December 1, 1992
Creator: Kim, K. J.; Chattopadhyay, S. & Shank, C. V.
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Partner: UNT Libraries Government Documents Department
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Polarized nature of synchrotron radiation

Description: Synchrotron radiation is inherently highly polarized, and this fact makes synchrotron radiation useful for probing the directional and/or helical nature of the matter via polarization sensitive experiment. Here we summarize briefly the nature of the polarization experiments and the polarization characteristics of synchrotron radiation. 12 refs., 3 figs.
Date: September 1, 1991
Creator: Kim, K. J.
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Partner: UNT Libraries Government Documents Department
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Stability and performance of CDRL-FEL (Chemical Dynamics Research Laboratory-Free Electron Laser)

Description: We study the performance of a proposed infrared free electron laser at Lawrence Berkeley Laboratory, which would be a user facility and therefore has a unique set of requirements in intensity, spectrum and stability. The output performance in intensity and spectrum, and methods to optimize the performance, are studied in detail. The effect of the electron beam fluctuation on FEL stability is carefully evaluated to set a tolerance for the accelerator design. Use of intracavity gratings is studie… more
Date: November 1, 1990
Creator: Kim, K. J. & Xie, M.
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Partner: UNT Libraries Government Documents Department
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The evolution and limits of spectral bandwidth in free electron lasers

Description: We study the bandwidths in free electron lasers (FELs) under different circumstances; for weakly saturated FELs in storage rings, the bandwidth is given be the formula derived in the super mode theory, while it is given by the Fourier transform of the electron pulse length in the strongly saturated FELs in linacs. The limiting bandwidth for the case of a DC beam is given by a Schawlow-Townes formula, but the approach to the limit is very slow. 14 refs.
Date: November 1, 1990
Creator: Kim, K. J.
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Partner: UNT Libraries Government Documents Department
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Achromatic and isochronous electron beam transport for tunable free electron lasers

Description: We have continued the study of a suitable electron beam transport line, which is both isochronous and achromatic, for the free electron laser being designed at Lawrence Berkeley Laboratory. A refined version of the beam transport optics is discussed that accommodates two different modes of FEL wavelength tuning. For the fine tuning involving a small change of the electron beam energy, sextupoles are added to cancel the leading nonlinear dispersion. For the main tuning involving the change of th… more
Date: September 1, 1991
Creator: Bengtsson, J. & Kim, K. J.
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Partner: UNT Libraries Government Documents Department
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Design overview of a highly stable infrared free electron laser at LBL

Description: An infrared free electron laser (IRFEL) is being designed for the Chemical Dynamics Research Laboratory (CDRL) at LBL. The FEL is based on a 50 MeV RF linac operating in synchronization to the Advanced Light Source (ALS), and will produce intense (100 {mu}J per micropulse), narrow bandwidth (narrower than 0.1%) radiation between 3 {mu} and 50 {mu}. In the design, we pay particular attention to the FEL stability issues and require that the fluctuations in electron beam energy and in timing be le… more
Date: November 1, 1990
Creator: Kim, K. J.; Berz, M.; Chattopadhyay, S.; Gough, R.; Kim, C.; Kung, A. H. et al.
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Partner: UNT Libraries Government Documents Department
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Requirements and design of a high stable infrared free electron laser at LBL

Description: An infrared free electron laser (IRFEL) is being designed for the Chemical Dynamics Research Laboratory (CDRL) at LBL. The FEL is based on a 50 MeV RF linac operating in synchronization to the Advanced Light Source (ALS), and will produce intense (100 {mu}J per micropulse), narrow bandwidth (narrower than 0.1%) radiation between 3 {mu} and 50 {mu}. In the design, we pay particular attention to the FEL stability issues and require that the fluctuations in electron beam energy and in timing be le… more
Date: June 1, 1990
Creator: Kim, K. J.; Berz, M.; Chattopadhyay, S.; Gough, R.; Kim, C.; Kung, A. H. et al.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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An infrared free electron laser system for the proposed Chemical Dynamics Research Laboratory at LBL based on a 500 MHz superconducting linac

Description: We describe a new design of the Infrared Free Electron Laser (IRFEL) for the proposed Chemical Dynamics Research Laboratory (CDRL) at LBL. The design and choice of parameters are dictated by the unique requirements of the CDRL scientific program. The accelerator system is based on the 500 MHz superconducting cavity technology to achieve a wavelength stability of 10[sup [minus]4].
Date: September 1, 1992
Creator: Kim, K. J.; Byrns, R.; Chattopadhyay, S.; Donahue, R.; Edighoffer, J.; Gough, R. et al.
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Partner: UNT Libraries Government Documents Department
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Design of a superconducting linear accelerator for an Infrared Free Electron Laser of the proposed Chemical Dynamics Research Laboratory at LBL

Description: An accelerator complex has recently been designed at LBL as part of an Infrared Free Electron Laser facility in support of a proposed Chemical Dynamics Research Laboratory. We will outline the choice of parameters and design philosophy, which are strongly driven by the demand of reliable and spectrally stable operation of the FEL for very special scientific experiments. The design is based on a 500 MHz recirculating superconducting electron linac with highest energy reach of about 60 MeV. The a… more
Date: August 1, 1992
Creator: Chattopadhyay, S.; Byrns, R.; Donahue, R.; Edighoffer, J.; Gough, R.; Hoyer, E. et al.
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Partner: UNT Libraries Government Documents Department
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Suppression of mode-beating in a saturated hole-coupled FEL oscillator

Description: In a hole-coupled resonator, either empty or loaded with a linear FEL gain medium, the phenomenon of mode-degeneracy and mode-beating have been studied. When the magnitudes of the eigenvalues, derived from a linear analysis, are equal for two or more dominant eigenmodes, the system cannot achieve a stable beam-profile. We investigate this phenomenon when a saturated FEL is present within the cavity, thus introducing non-linearity. We use a three-dimensional FEL oscillator code, based on the amp… more
Date: August 1, 1992
Creator: Krishnagopal, S.; Xie, M. & Kim, K. J.
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Partner: UNT Libraries Government Documents Department
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Summary of the linac based radiation sources working group

Description: Technological advances have occurred in the past few years that have made linac based Free-Electron Lasers (FEL) promising candidates for the generation of short wavelength radiation. Although the FELs use undulators or wigglers, they produce stimulated radiation rather than the spontaneous emission found in insertion devices on the second and third generation sources of today. This stimulated emission process endows the FEL with properties presenting unique opportunities in many fields of scie… more
Date: January 1, 1992
Creator: Ben-Zvi, Ilan; Corbett, J.; Johnson, E.; Kim, K. J. & Sheffield, R.
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Partner: UNT Libraries Government Documents Department
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Self-amplified spontaneous emission for short wavelength coherent radiation

Description: We review the recent progress in our understanding of the self-amplified spontaneous emission (SASE), emphasizing the application to short wavelength generation. Simple formulae are given for the start-up, exponential gain and the saturation of SASE. Accelerator technologies producing high brightness electron beams required for short wavelength SASE are discussed. An example utilizing electron beams from a photocathode-linac system to produce 4nm SASE in the multigigawatt range is presented.
Date: September 1, 1992
Creator: Kim, K. J. & Xie, M.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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A technique for single-pulse spectrum and pulse width measurements for an IR-FEL

Description: A diagnostic system has been designed to measure the spectrum and pulse width of infrared FEL pulses. Use of an image dissector [1] and a single element high speed detector with integrating sphere, allows one to obtain spectral or temporal information for each individual micro-pulse inside the pulse train. The spectral diagnostic consists of a mode matching telescope, a high resolution spectrometer, an imaging telescope and an image dissector system. The imaging telescope between the spectrogra… more
Date: August 1, 1992
Creator: Leemans, W. P.; Edighoffer, J. A.; Kim, K. J.; Chattopadhyay, S. (Lawrence Berkeley Lab., CA (United States)) & Schwettman, H.A. (Stanford Univ., CA (United States). W.W. Hansen Labs. of Physics)
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Partner: UNT Libraries Government Documents Department
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Femtosecond X-Ray Generation Through 90° Thomson Scattering: Status of the LBL Experiment

Description: Scattering of femotosecond laser pulses off a low energy relativistic electron beam at 90{sup o} offers the possibility to generate ultrashort X-ray pulses. Experiments are under preparation in the Beam Test Facility of the Center for Beam Physics at LBL to demonstrate the generation and detection of such pulses. The experiments involve a relativistic electron beam (tunable from 25-50 MeV) with a bunch length of 10 ps containing 1-2 nC, and an ultra short pulse (50-200 fs), high peak power (&gt… more
Date: November 1, 1994
Creator: Leemans, W.; Schoenlein, R.; Chin, A.; Glover, E.; Conde, M.; Chattopadhyay, S. et al.
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Partner: UNT Libraries Government Documents Department
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Linac Coherent Light Source (LCLS) at 2--4 nm using the SLAC linac

Description: The authors describe the possible use of the SLAC linac to drive a unique, powerful, short wavelength Linac Coherent Light Source (LCLS). Using the FEL principle, lasing is achieved in a single pass of a high peak current electron beam through a long undulator by self-amplified-spontaneous-emission (SASE). The main components are a high-brightness electron RF gun with a photocathode, two electron bunch length compressors, the existing SLAC linac, beam diagnostics, and a long undulator combined … more
Date: August 1, 1993
Creator: Seeman, J. T.; Bane, K.; Boyce, R.; Loew, G.; Morton, P.; Nuhn, H. D. et al.
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Partner: UNT Libraries Government Documents Department
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Time-dependent multi-dimensional simulation studies of the electron output scheme for high power FELs

Description: The authors examine the performance of the so-called electron output scheme recently proposed by the Novosibirsk group. In this scheme, the key role of the FEL oscillator is to induce bunching, while an external undulator, called the radiator, then outcouples the bunched electron beam to optical energy via coherent emission. The level of the intracavity power in the oscillator is kept low by employing a transverse optical klystron (TOK) configuration, thus avoiding excessive thermal loading on … more
Date: December 1, 1994
Creator: Hahn, S. J.; Fawley, W. M.; Kim, K. J. & Edighoffer, J. A.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

Self-amplified spontaneous emission for short wavelength coherent radiation

Description: We review the recent progress in our understanding of the self-amplified spontaneous emission (SASE), emphasizing the application to short wavelength generation. Simple formulae are given for the start-up, exponential gain and the saturation of SASE. Accelerator technologies producing high brightness electron beams required for short wavelength SASE are discussed. An example utilizing electron beams from a photocathode-linac system to produce 4nm SASE in the multigigawatt range is presented.
Date: September 1, 1992
Creator: Kim, K. J. & Xie, M.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Experiment and simulation of hole-coupled resonator modes with a CW HeNe laser

Description: The Infrared Free Electron Laser (IRFEL) for the proposed Chemical Dynamics Laboratory at Lawrence Berkeley Laboratory will operate from 3 - 50 {mu}m and use all-metal optics. This choice of optics allows for broad tuning and has excellent power-handling capabilities. A hole-coupling approach for the optical resonator was adopted after extensive computer simulations verified that it fully met the design requirements. To bench-test the simulations we have carried out a scaled cavity experiment u… more
Date: August 1, 1992
Creator: Leemans, W. P.; Xie, M.; Edighoffer, J. A.; Wallace, E.; Kim, K. J. & Chattopadhyay, S.
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Partner: UNT Libraries Government Documents Department
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Experimental test of hole-coupled FEL resonator designs using a CW-HeNe laser

Description: We report on ongoing experiments and simulations which model the performance of hole-coupled resonators. We have previously studied a hole-coupled resonator which was well inside the stable region (stability parameter g = {minus}0.8). In the far field, good agreement between experiment and simulation was obtained for both the intracavity and outcoupled mode-profile. The present study involves a resonator with a stability parameter of {minus}0.987, identical to the stability parameter of the pro… more
Date: January 1, 1993
Creator: Leemans, W. P.; Wallace, E. W.; Xie, M. & Kim, K. J.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

Summary of the linac based radiation sources working group

Description: Technological advances have occurred in the past few years that have made linac based Free-Electron Lasers (FEL) promising candidates for the generation of short wavelength radiation. Although the FELs use undulators or wigglers, they produce stimulated radiation rather than the spontaneous emission found in insertion devices on the second and third generation sources of today. This stimulated emission process endows the FEL with properties presenting unique opportunities in many fields of scie… more
Date: October 1, 1992
Creator: Ben-Zvi, Ilan; Corbett, J.; Johnson, E.; Kim, K. J. & Sheffield, R.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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