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in creator/contributor: "Kim, K. J."

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Femtosecond X-rays from 90{degree} Thomson scattering

The authors report on progress on the femtosecond X-ray pulse generation experiment. The experiment involves a relativistic electron beam (50 MeV) with an rms bunch length of 10 ps containing 1--2 nC of charge, and a ultrashort pulse (50--200 fs), high power (< 4 TW) 0.8 {micro}m laser beam from a Ti:Al{sub 2}O{sub 3} laser system. Both beams are focused down to about a 50 {micro}m waist size and intersect at 90{degree}. The laser field acts as an electromagnetic undulator for the relativistic … more

Date: April 1, 1995

Creator: Leemans, W.; Schoenlein, R.; Chin, A.; Glover, E.; Govil, R.; Volfbeyn, P. et al.

Item Type: Article

Partner: UNT Libraries Government Documents Department

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Experiment and simulation of hole-coupled resonator modes with a CW HeNe laser

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.

Item Type: Article

Partner: UNT Libraries Government Documents Department

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Experimental test of hole-coupled FEL resonator designs using a CW-HeNe laser

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: Article

Partner: UNT Libraries Government Documents Department

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Achromatic and Isochronous Electron Beam Transport for Tunable Free Electron Lasers

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 1991

Creator: Bengtsson, J. & Kim, K. J.

Item Type: 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

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.

Item Type: Article

Partner: UNT Libraries Government Documents Department

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Crab crossing in a gamma-gamma collider

The crabbing of an incident photon beam from a laser, and the electron beam with which it interacts at the conversion point, is shown to have the same efficiency as in head-on Compton scattering, but with the advantages of a crossing geometry. The resulting {gamma}-ray beam is also crabbed, which allows for a crossing collision point, while maintaining the luminosity at the same value it would have in a head-on collision.

Date: August 1, 1994

Creator: Xie, M.; Kim, K. J. & Sessler, A.

Item Type: Article

Partner: UNT Libraries Government Documents Department

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Polarized nature of synchrotron radiation

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.

Item Type: Article

Partner: UNT Libraries Government Documents Department

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Generation of angular-momentum-dominated electron beams from a photoinjector

Various projects under study require an angular-momentum-dominated electron beam generated by a photoinjector. Some of the proposals directly use the angular-momentum-dominated beams (e.g. electron cooling of heavy ions), while others require the beam to be transformed into a flat beam (e.g. possible electron injectors for light sources and linear colliders). In this paper, we report our experimental study of an angular-momentum-dominated beam produced in a photoinjector, addressing the depende… more

Date: November 1, 2004

Creator: Sun, Y. E.; Piot, P.; Kim, K. J.; Barov, N.; Lidia, S.; Santucci, J. et al.

Item Type: Article

Partner: UNT Libraries Government Documents Department

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Suppression of mode-beating in a saturated hole-coupled FEL oscillator

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.

Item Type: Article

Partner: UNT Libraries Government Documents Department

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Electron quantum yields from a barium photocathode illuminated with polarized light

Photoemission measurements with a barium photo-cathode and a nitrogen laser are reported. The cathode is prepared by evaporating barium onto a copper disc. Radiation from a nitrogen laser (337 nm, 10 ns) is polarized and strikes the cathode surface at variable angles. An electron quantum yield as high as 1 {times} 10{sup {minus}3} is observed. The dependence of the quantum yield on the beam polarization and angle of incidence is investigated. The results indicate that higher quantum yields are … more

Date: May 1, 1993

Creator: Conde, M. E.; Chattopadhyay, S.; Kim, K. J.; Kwon, S. I.; Leung, K. N. & Young, A. T.

Item Type: Article

Partner: UNT Libraries Government Documents Department

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The 50 MeV Beam Test Facility at LBL

A new beam line, expected to be built by September 1993, will transport the 50 MeV electron beam from the ALS LINAC into an experimental area to support various R&D activities in the Center for Beam Physics at LBL. A variety of experiments are planned involving the interaction of such a relativistic electron beam with plasmas (plasma focusing), laser beams (generation of femtosecond X-ray pulses) and electromagnetic cavities (Crab cavities etc....). The beam line is designed using the measured … more

Date: May 1, 1993

Creator: Leemans, W.; Behrsing, G.; Kim, K. J.; Krupnick, J.; Matuk, C.; Selph, F. et al.

Item Type: Article

Partner: UNT Libraries Government Documents Department

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Transverse-to-Longitudinal Emittance Exchange to Improve Performance of High-Gain Free-Electron Lasers

The ability to generate small transverse emittance is perhaps the main limiting factor for the performance of high-gain x-rays free-electron lasers (FELs). Noting that beams from an rf photocathode gun can have energy spread much smaller than required for efficient FEL interaction, we present a method to produce normalized transverse emittance at or below about 0.1 {micro}m, which will lead to a significantly shorter length undulator as well as a lower electron beam energy for an x-ray FEL proj… more

Date: September 21, 2006

Creator: Emma, P.; Huang, Z.; Kim, K. J. & Piot, P.

Item Type: Article

Partner: UNT Libraries Government Documents Department

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Towards advanced electron beam brightness enhancement and conditioning.

The importance of developing higher-brightness electron beam sources for future accelerators was emphasized during the DOE-BESAC Subcommittee Meeting on the BES 20-Year Facility Roadmap held in Washington on February 20, 2003 [1]. The Subcommittee made a strong recommendation for an R&D program for high-brightness gun development. Spurred by this recommendation, a workshop was organized at Argonne National Laboratory on September 22-26, 2003 under the auspices of the ANL Theory Institute. A… more

Date: May 11, 2004

Creator: Kim, K. J.; Carlsten, B.; Dowell, D.; Flottmann, K.; Jensen, K.; Petillo, J. et al.

Item Type: Report

Partner: UNT Libraries Government Documents Department

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X-ray based sub-picosecond electron bunch characterization using 90{sup o} Thomson scattering

No Description Available.

Date: June 1996

Creator: Leemans, W. P.; Schoenlein, R. W.; Volfbeyn, P.; Chin, A. H.; Glover, T. E.; Balling, P. et al.

Item Type: Article

Partner: UNT Libraries Government Documents Department

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Analysis of optical stochastic cooling including transverse effects

The phase space area plays an important role in determining the performance of optical stochastic cooling. Specifically, the number of samples in the beam consists of three factors corresponding to three dimensions, the factor in each dimension being given by the ratio of the total phase space area in that dimension to the radiation wavelength.

Date: May 1, 1995

Creator: Kim, K. J. & Zege, A. V.

Item Type: Article

Partner: UNT Libraries Government Documents Department

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FEL options for power beaming

The demand for the output power of communication satellites has been increasing exponentially. The satellite power is generated from solar panels which collect the sunlight and convert it to electrical power. The power per satellite is limited due to the limit in the practical size of the solar panel. One way to meet the power demand is to employ multiple satellites (up to 10) per the internationally agreed-upon ``slot`` in the geosynchronous earth orbit (GEO). However, this approach is very ex… more

Date: October 1, 1997

Creator: Kim, K. J.; Zholents, A. A.; Zolotorev, M. S. & Vinokurov, N. A.

Item Type: Article

Partner: UNT Libraries Government Documents Department

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Gamma-gamma colliders

Gamma-gamma colliders make intense beams of gamma rays and have them collide so as to make elementary particles. The authors show, in this article, that constructing a gamma-gamma collider as an add-on to an electron-positron linear collider is possible with present technology and that it does not require much additional cost. Furthermore, they show that the resulting capability is very interesting from a particle physics point of view. An overview of a linear collider, with a second interactio… more

Date: June 1, 1996

Creator: Kim, K. J. & Sessler, A.

Item Type: Report

Partner: UNT Libraries Government Documents Department

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UV x-ray free electron lasers through high-gain single pass amplifier: Basic principles and issues

The author reviews the basic principles of high gain free electron laser amplifier in single pass configuration for generation of intense, tunable radiation for wavelength shorter than 1,000 {angstrom}. Two schemes are discussed: for wavelength region between 1,000--100 {angstrom}, the high gain harmonic generation of a coherent input radiation can be used. For x-ray wavelength as short as a few {angstrom}, the self-amplified spontaneous emission is currently the only known free electron laser … more

Date: September 1, 1994

Creator: Kim, K. J.

Item Type: Article

Partner: UNT Libraries Government Documents Department

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The FEL development at the Advanced Photon Source.

Construction of a single-pass free-electron laser (FEL) based on the self-amplified spontaneous emission (SASE) mode of operation is nearing completion at the Advanced Photon Source (APS) with initial experiments imminent. The APS SASE FEL is a proof-of-principle fourth-generation light source. As of January 1999 the undulator hall, end-station building, necessary transfer lines, electron and optical diagnostics, injectors, and initial undulatory have been constructed and, with the exception of… more

Date: March 15, 1999

Creator: Arnold, N. D.; Benson, C.; Berg, S.; Berg, W.; Biedron, S. G.; Chae, Y. C. et al.

Item Type: Article

Partner: UNT Libraries Government Documents Department

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Collective effects in isochronous storage rings

We studied the collective instabilities in isochronous storage rings using a linac-type analysis. Simple criteria for avoiding the longitudinal and transverse instabilities are developed by employing a two-particle model. Numerical examples show that these conditions do not impose serious performance restrictions for two of the currently proposed isochronous storage rings.

Date: January 1, 1996

Creator: Chao, A. W. & Kim, K. J.

Item Type: Article

Partner: UNT Libraries Government Documents Department

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Undulator interruption in high-gain free electron lasers

The effect of interrupting an undulator on the performance of high-gain free-electron lasers (FELs) is evaluated by analyzing 1-D Maxwell-Vlasov equations. It is found that the effect is small for a reasonable length of the interruptions for FEL parameters envisaged for short wavelength self-amplified spontaneous emission (SASE). Since the interruptions provide valuable space for quadrupoles and diagnostics, and at the same time permit a greater flexibility in mechanical design, the result of t… more

Date: October 1, 1997

Creator: Kim, K. J.

Item Type: Report

Partner: UNT Libraries Government Documents Department

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Critical issues for high-power FEL based on microtron recuperator/electron out-coupling scheme

The FELs based on the RF accelerator-recuperator and the electron outcoupling is promising for obtaining average output power of hundreds of kilowatts. We present basic considerations for the system stability and performance optimization for this scheme.

Date: March 1, 1997

Creator: Vinokurov, N. A.; Zholents, A. A.; Fawley, W. M. & Kim, K. J.

Item Type: Article

Partner: UNT Libraries Government Documents Department

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Linac-based, intense, coherent x-ray source using self-amplified spontaneous emission

In this article, the author discusses the principles of self-amplified spontaneous emission (SASE), how the SASE could be the basis of next generation light sources exceeding the current performance -- by many orders of magnitude in spectral brightness, and by a factor of a hundred in time resolution. He also discusses how the SLAC linac, due to its high energy and its precision control, is ideally suited for the x-ray SASE. Therefore, using the SLAC linac for generation of x-ray SASE for the f… more

Date: September 1, 1997

Creator: Kim, K. J.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Solution to the initial value problem for a high-gain FEL via Van Kampen's method.

Using Van Kampen's normal mode expansion, we solve the initial value problem for a high-gain free-electron laser (FEL) described by the three-dimensional Maxwell-Klimontovich equations. An expression of the radiation spectrum is given for the process of coherent amplification and self-amplified spontaneous emission. It is noted that the input coupling coefficient for either process increases with the initial beam energy spread. The effective start-up noise is identified as the coherent fraction… more

Date: August 22, 2000

Creator: Huang, Z. & Kim, K. J.

Item Type: Article

Partner: UNT Libraries Government Documents Department