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Long wavelength end-effect undulator radiation (Transition Undulator Radiation)

Description: As first pointed out by K.-J. Kim, undulator radiation contains a broad-band component in the long wavelength region. This radiation is due to the change in longitudinal velocity of an electron upon entering and leaving an undulator. The radiation pattern is a hollow cone, peaked in the forward direction, with an opening angle of approximately 1/{gamma}, with a spectrum covering a wide range, including the infra-red and the visible. The radiation is radially polarized, analogous to transition radiation, and exhibits interference effects between the entrance and exit ends of the undulator, similar to the interference effects observed for transition radiation from a thin slab of material. A straightforward application of formulas from Jackson ({ital Classical Electrodynamics}) results in a closed form exact expression for the low frequency limit of this novel radiation effect, Transition Undulator Radiation or TUR. 3 refs., 3 figs.
Date: January 29, 1996
Creator: Kincaid, B.M.
Partner: UNT Libraries Government Documents Department

Some practical aspects of undulator radiation properties

Description: It is important to be able to accurately predict the spectral and angular distribution of undulator radiation properties when designing beamlines; at new synchrotron radiation facilities or when performing radiation experiments at already existing beamlines. In practice, the particle beam emittance and beam energy spread must be taken into account in modeling these properties. The undulators fabricated today are made with small RMS phase errors, making them perform almost as, ideal devices. Calculation tools for numerical modeling of undulator radiation sources (ideal and nonideal) will be discussed, and the excellent agreement with experimentally obtained absolute spectral flux measurements of undulator A at the Advanced Photon Source verifies the high accuracy of the computer codes and the high quality of the undulators being built today. Our focus here is on flux properties useful in practical beamline designs, and the chosen examples demonstrate the versatility of computer programs available to beamline designers and experimentalists.
Date: November 1996
Creator: Ilinski, P.; Dejus, R. J.; Gluskin, E. & Morrison, T. I.
Partner: UNT Libraries Government Documents Department

Energy and angular distributions of radiation power from bending magnet and wiggler sources at a 6-GeV ring

Description: In order to design radiation ports and beam line components, it is essential to understand the distribution of power from a radiation source as a function of both the photon energy and the solid angle of emission. In this preliminary note, we assemble all the formula involved for the case of a bending magnet and a wiggler. Typical distributions are presented for the case of 6-Gev radiation.
Date: September 25, 1985
Creator: Shenoy, G.K. & Viccaro, P.J.
Partner: UNT Libraries Government Documents Department

Observation of SASE at 47 {mu}m

Description: Coherent, far-infrared undulator radiation from sub-picosecond electron pulses has been observed at the Stanford SUNSHINE facility. Measured intensities exceed theoretical prediction for spontaneous radiation by more than an order of magnitude. The forward-radiated energy from a 16MeV electron beam traveling in a single pass through an undulator with a strength parameter K = 0.6 grows exponentially and is consistent with predictions of Self-Amplified Spontaneous Emission (SASE) with a gain length of 45.4cm or 5.9 undulator periods.
Date: August 1995
Creator: Bocek, D.; Kung, P. & Lihn, Hung-chi
Partner: UNT Libraries Government Documents Department

Synchrotron radiation from protons

Description: Synchrotron radiation from protons, though described by the same equations as the radiation from electrons, exhibits a number of interesting features on account of the parameters reached in praxis. In this presentation, we shall point out some of the features relating to (i) normal synchrotron radiation from dipoles in proton machines such as the High Energy Booster and the Superconducting Super Collider; (ii) synchrotron radiation from short dipoles, and its application to light monitors for proton machines, and (iii) synchrotron radiation from undulators in the limit when, the deflection parameter is much smaller than unity. The material for this presentation is taken largely from the work of Hofmann, Coisson, Bossart, and their collaborators, and from a paper by Kim. We shall emphasize the qualitative aspects of synchrotron radiation in the cases mentioned above, making, when possible, simple arguments for estimating the spectral and angular properties of the radiation. Detailed analyses can be found in the literature.
Date: December 1, 1992
Creator: Dutt, S.K.
Partner: UNT Libraries Government Documents Department

Transition undulator radiation as bright infrared sources

Description: Undulator radiation contains, in addition to the usual component with narrow spectral features, a broad-band component in the low frequency region emitted in the near forward direction, peaked at an angle 1/{gamma}, where {gamma} is the relativistic factor. This component is referred to as the transition undulator radiation, as it is caused by the sudden change in the electron`s longitudinal velocity as it enters and leaves the undulator. The characteristics of the transition undulator radiation are analyzed and compared with the infrared radiation from the usual undulator harmonics and from bending magnets.
Date: December 1, 1994
Creator: Kim, Kwang-Je
Partner: UNT Libraries Government Documents Department

Report of the working group on far-field accelerators

Description: This report describes the work of the Group on Far Field Accelerators. The work was focused on two accelerator schemes, the Inverse Free Electron Laser and the Two Wave Device. The possibilities and limitations of these two accelerators are discussed, as well as some of the requiremenets on the laser necessary to reach very high energies. A conceptual design of a single pass Inverse Free Electron Laser is presented.
Date: February 1, 1982
Creator: Pellegrini, C.
Partner: UNT Libraries Government Documents Department

Reduction of undulator radiation and FEL small gain due to wiggler errors

Description: A deterministic approach is taken to study the effect of errors in the wiggler magnet field on the spontaneous emission and the gain of Free Electron Lasers. A 3D formulation is used to derive the reduction in spontaneous emission due to changes in the time of flight of the electrons. A generalization of Madey's theorem to 3D is then used to calculate the reduction in the FEL small gain. 6 refs.
Date: January 1, 1991
Creator: Friedman, A.
Partner: UNT Libraries Government Documents Department

Research opportunities at the advanced light source

Description: The Advanced Light Source (ALS), now under construction at the Lawrence Berkeley Laboratory, is a third-generation synchrotron radiation facility based on a low-emittance, 1.5-GeV electron storage ring with 10 long straight sections available for insertion devices and, initially, 24 bend-magnet ports. Undulators will provide high-brightness radiation at photon energies from below 10 eV to above 2 keV; wiggler and bend-magnet radiation will extend the spectral coverage with high fluxes to above 10 keV. Scheduled to begin operations as a US Department of Energy national user facility in the spring of 1993, the ALS will support an extensive research program in which soft x-ray and ultraviolet radiation is used to study matter in all its varied gaseous, liquid, and solid forms. Participating research teams to implement the initial scientific program have been selected. 13 refs., 3 figs., 2 tabs.
Date: September 26, 1990
Creator: Robinson, A.L. & Schlachter, A.S.
Partner: UNT Libraries Government Documents Department

The challenges of third-generation synchrotron light source

Description: Third-generation synchrotron light sources are specifically designed to operate with long insertion devices that produce very high brightness beams of synchrotron radiation. There are many such facilities now under construction, or in the design stage, all over the world. After a brief review of the main properties of the low emittance storage rings that form the heart of these facilities, we will discuss the particular challenges that accompany their design. These include: the effects of the strong sextupoles required for chromatic correction of the low emittance lattices; impact of machine imperfections on the dynamic aperture; the effects of the linear and nonlinear magnetic fields of the undulators; impedance consequences of long, narrow, undulator vacuum vessels; injection; and beam lifetime. As examples, we take the Advanced Light Source, currently under construction at the Lawrence Berkeley Laboratory, USA, and the European Synchrotron Radiation Facility under construction in Grenoble, France. 8 refs., 8 figs., 1 tab.
Date: August 1, 1989
Creator: Jackson, A.
Partner: UNT Libraries Government Documents Department

Comparison of sideband spectra obtained from analytical formula and from numerical simulation in free-electron laser

Description: The sideband spectrum appearing in the free-electron laser is analyzed. For an untapered undulator, we predict the wavelengths of local peaks arising from the sidebands; they are compared with numerical simulations. In our analytical theory, three laser-driving terms are derived. One term does not chirp in frequency, drives a number of frequencies simultaneously, and is always the strongest term with a fixed strength. The other two driving terms, which also drive multiple frequencies, chirp to both directions from a resonant frequency. We assume that the sidebands originate from a dipole oscillation of average electron energy. This oscillation frequency is equal to the synchrotron oscillation frequency. The theory predicts that the strength of the chirping terms is proportional to the amplitude of the dipole moment.
Date: January 1, 1987
Creator: Takeda, H.
Partner: UNT Libraries Government Documents Department

Characteristics of the 7-GeV advanced photon source: A guide for users

Description: In this document we present the characteristics of the electromagnetic radiation from various types of sources on the 7-GeV Advanced Photon Source (APS) storage ring. The sources include bending magnets, undulators, and wigglers. The characteristics are compared with those of other synchrotron sources when operated at their design specifications. The influence of positron beam size on the on-axis brilliance is discussed, along with the power distribution from these sources. The goal of this document is to provide users with enough information on the characteristics of radiation from the APS storage ring so that experiments can be efficiently planned. 23 refs., 20 figs., 8 tabs.
Date: February 1, 1988
Creator: Shenoy, G.K.; Viccaro, P.J. & Mills, D.M.
Partner: UNT Libraries Government Documents Department

Real world issues for the new soft x-ray synchrotron sources

Description: A new generation of synchrotron radiation light sources covering the VUV, soft x-ray and hard x-ray spectral regions is under construction in several countries. They are designed specifically to use periodic magnetic undulators and low-emittance electron or positron beams to produce high-brightness near-diffraction-limited synchrotron radiation beams. An introduction to the properties of undulator radiation is followed by a discussion of some of the challenges to be faced at the new facilities. Examples of predicted undulator output from the Advanced Light Source, a third generation 1--2 GeV storage ring optimized for undulator use, are used to highlight differences from present synchrotron radiation sources, including high beam power, partial coherence, harmonics, and other unusual spectral and angular properties of undulator radiation. 8 refs., 2 figs.
Date: May 1, 1991
Creator: Kincaid, B.M.
Partner: UNT Libraries Government Documents Department

Brightness and coherence of radiation from undulators and high-gain free electron lasers

Description: The purpose of this paper is to review the radiation characteristics of undulators and high-gain free electron lasers (FELs). The topics covered are: a phase-space method in wave optics and synchrotron radiation, coherence from the phase-space point of view, discussions of undulator performances in next-generation synchrotron radiation facility and the characteristics of the high-gain FELs and their performances. (LSP)
Date: March 1, 1987
Creator: Kim, Kwang-Je
Partner: UNT Libraries Government Documents Department

An ALS handbook: A summary of the capabilities and characteristics of the advanced light source

Description: This booklet aims to provide the prospective user of the Advanced Light Source with a concise description of the radiation a researcher might expect at his or her experimental station. The focus is therefore on the characteristics of the light that emerges from insertion devices and bending magnets and on how components of the beam lines further alter the properties of the radiation. The few specifications and operating parameters of the ALS storage ring that are of interest are those that directly determine the radiation characteristics. Sections 4 through 5 are primarily devoted to summary presentations, by means of performance plots and tabular compilations, of radiation characteristics at the ALS--spectral brightness, flux, coherent power, resolution, etc.--assuming a representative set of three undulators and one wiggler and a corresponding set of four beam lines. As a complement to these performance summaries, Section 1 is a general introductory discussion of synchrotron radiation and the ALS, and Section 2 discusses the properties of the stored electron beam that affect the radiation. Section 3 then provides an introduction to the characteristics of synchrotron radiation from bending magnets, wigglers, and undulators. In addition, Section 5 briefly introduces the theory of diffraction-grating and crystal monochromators. As compared with previous editions of this booklet, the performance plots and tabular compilations of the ALS radiation characteristics are now based on conservative engineering designs rather than preliminary physics designs.
Date: April 1, 1989
Creator: Available, Not
Partner: UNT Libraries Government Documents Department

The Advanced Light Source: A new tool for research in atomic physics

Description: The Advanced Light Source, a third-generation national synchrotron-radiation facility now under construction at the Lawrence Berkeley Laboratory in Berkeley, California, is scheduled to begin serving qualified users across a broad spectrum of research areas in the spring of 1993. Undulators will generate high-brightness, partially coherent, plane polarized, soft-x-ray and ultraviolet (XUV) radiation from below 10 eV to above 2 keV. Wigglers and bend magnets will generate high fluxes of x-rays to photon energies above 10 keV. The ALS will have an extensive research program in which XUV radiation is used to study matter in all its varied gaseous, liquid, and solid forms. 7 refs., 3 figs.
Date: September 1, 1990
Creator: Schlachter, A.S.
Partner: UNT Libraries Government Documents Department

Coherent radiation in an undulator

Description: This paper is concerned with the synchrotron radiation from an undulating electron beam in a rectangular waveguide. The analysis is based on the dyadic Green's function approach to solve Maxwell's equations in terms of the vector potential. It is shown analytically and numerically that the radiated energy spectrum may differ significantly from the free space results when the undulator length divided by the Lorentz factor of the electron beam is larger than the transverse size of the waveguide. Then, the appearance of the spectrum is changed into a small number of sharp peaks, each corresponding to an excited waveguide mode. The undulator radiation is identified with the wake field in beam instabilities. The concepts of wake function and impedance are introduced to formulate the present problem in the same manner as the beam instability problem, so that the accumulated techniques of the latter can be applied. It is shown that the obtained impedances satisfy the Panofsky-Wenzel theorem and other properties inevitable for wake fields. 4 refs., 2 figs.
Date: December 1, 1990
Creator: Chin, Yong Ho.
Partner: UNT Libraries Government Documents Department

Soft x-ray imaging with 35 period undulator at the NSLS

Description: Prior to the Phase II shutdown at the National Synchrotron Light Source (NSLS) in March 1987, a 10-period mini-undulator was used for soft x-ray imaging on the temporary X-17T beamline for six months. During this brief period we gained considerable experience in the use of undulator radiation for high brightness applications, including the use of high power optics, and position feedback. We commissioned a new scanning microscope using high resolution zone plates, and a fast laser interferometer. The microscope made it possible to study zymogen granules (subcellular structures which play an important role in the secretion of digestive enzymes in the pancreas) in an unaltered state: whole, unfixed, unstained and suspended in water. The first images displayed a distribution of material different than that seen in electron microscopy. In addition, fixed and air dried zymogen granules were the subject of Gabor holography. During the Phase II shutdown we made major changes to the entire system. At the present time the installation and commissioning of the new permanent line at beamline X-1A is at an advanced stage. The design, performance and the projected experimental program of this facility is the subject of this paper. 18 refs., 3 figs., 4 tabs.
Date: January 1, 1988
Creator: Buckley, C.; Rarback, H.; Alforque, R.; Shu, D.; Ade, H.; Hellman, S. et al.
Partner: UNT Libraries Government Documents Department

Photoneutron generation with electron undulators

Description: An extremely compact line-geometry pulsed source of photoneutrons is proposed with controllable energies of only a few kiloelectron volts, average yields exceeding 1(13) per second, peak intensities higher than the average by two or three orders of magnitude, controllable polarization, and pulse durations of about 2 ns. This source uses photons from a magnetic undulator in a 30-GeV electron-storage ring. Parameters of the undulator and storage ring are stringent but probably attainable with careful design and construction. Several applications are discussed.
Date: December 1, 1981
Creator: Baldwin, G.C.
Partner: UNT Libraries Government Documents Department

Center for X-Ray Optics, 1986

Description: The Center for X-Ray Optics has made substantial progress during the past year on the development of very high resolution x-ray technologies, the generation of coherent radiation at x-ray wavelengths, and, based on these new developments, had embarked on several scientific investigations that would not otherwise have been possible. The investigations covered in this report are topics on x-ray sources, x-ray imaging and applications, soft x-ray spectroscopy, synchrotron radiation, advanced light source and magnet structures for undulators and wigglers. (LSP)
Date: July 1, 1987
Creator: Available, Not
Partner: UNT Libraries Government Documents Department