In Search Of A Meaningful Field-error Specification For Wigglers

Bobbs, Bradley; Rakowsky, G.; Kennedy, Paul K.; Cover, Ralph A.; Slater, David W.

doi:10.1109/fel.1989.716070

Cited by 4 publications

(5 citation statements)

References 2 publications

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“…Bobbs proposed the phase error as a far better suited quality criterion because it is closely correlated to the spectral performance (Bobbs et al 1990). For small angles x 0 ; y 0 , the phase difference between the electron and the generated photon beam is given by the integral over the trajectory: …”

Section: Limitations Due To Emittance Energy Spread and Field Errorsmentioning

confidence: 98%

Shaping Photon Beams with Undulators and Wigglers

Bahrdt¹

2014

Synchrotron Light Sources and Free-Electron Lasers

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Periodic magnetic structures, i.e., undulators and wigglers, have been used for nearly 40 years as sources of brilliant synchrotron radiation. Today, sophisticated undulator designs provide many degrees of freedom such as photon beam energy, variable polarization, and orbital angular momentum. Specific designs efficiently suppress higher orders or reduce the on-axis power density. All tuning parameters are required to be freely accessible by the users. Still, the majority of undulators is based on permanent magnets with a clear trend to short periods and in-vacuum and cryogenically cooled systems. Similar designs are used for storage rings and free electron lasers, though the field quality requirements are different. Today, the optimization of a specific experiment follows a global approach. This includes not only the undulator design itself but also local lattice modifications to cope with ambitious designs, elaborate tracking schemes to estimate the impact on the dynamic aperture, and last but not least radiation propagation tools which transport a realistic photon beam phase space to the sample. This chapter summarizes the theory of undulator radiation and reviews the technological realization of undulators and wigglers. Operational issues are discussed, as well.

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Section: Limitations Due To Emittance Energy Spread and Field Errorsmentioning

confidence: 98%

Shaping Photon Beams with Undulators and Wigglers

Bahrdt¹

2014

Synchrotron Light Sources and Free-Electron Lasers

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“…In order to perform optimization over a population of candidate magnet orderings it is necessary to evaluate each ordering such that they can be compared and ranked. Designing objective functions that are robust and provide a meaningful landscape on the search space to optimize over is vital to achieving good stability and strong solutions [1].…”

Section: Objective Functionsmentioning

confidence: 99%

Using Artificial Immune Systems to Sort and Shim Insertion Devices at Diamond Light Source

Whittle

Basham

Patel

et al. 2022

J. Phys.: Conf. Ser.

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This work presents the Opt-ID software developed by the Rosalind Franklin Institute (RFI) and Diamond Light Source (DLS) in collaboration with Helmholtz-Zentrum Berlin (HZB). Opt-ID allows for efficient simulation of synchrotron Insertion Devices (ID) and the B fields produced by a given arrangement of candidate magnets. It provides an optimization framework built on the Artificial Immune System (AIS) algorithm for swapping and adjusting magnets within an ID to observe how these changes would affect the magnetic field of a real-world device, guiding ID builders in the steps they should take during ID tuning. Code for Opt-ID is provided open-source under the Apache-2.0 License on Github: https://github.com/rosalindfranklininstitute/Opt-ID

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“…Understanding the effects of wiggler errors [1][2][3][4][5][6][7][8] is of critical importance in the design of free electron lasers, There has been recent work aimed at determining the tolerances which must be imposed on the allowable field errors. Analytic results have been obtained for the effect of wiggler errors on the electron trajectory [7], and for the gain reduction in the low gain regime [5,6]. Computer simulations have been carried out both in the low [ 6,8] and high gain [ 3,4] regimes.…”

Section: Introductionmentioning

confidence: 99%

Reduction of FEL gain due to wiggler errors

Krinsky

Friedman

et al. 1992

Nuclear Instruments and Methods in Physics Research Section A:

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For an FEL operating in the exponential regime before saturation, we consider the effect on the gain of longitudinal velocity variations arising from wiggler field errors. The average gain reduction and the width of the output power distribution are expressed in terms of the mean square average of the ponderomotive phase shift per gain length. A scheme for correcting the electron trajectory using position monitors and dipole correctors is analyzed. Analytic results are compared with numerical simulations. Our work is directly applicable to the design of FEL amplifiers and the results are encouraging for the feasibility of such devices. DISCLAIMER This report was prepared as an account of work sponsored by an agency of the United States Government. Neither the United States Government nor any agency thereof, nor any of their employees, makes any warranty, express or implied, or assumes any legal liability or responsibility for the accuracy, completeness, oy usefulness of any information, apparatus, product, or process disclosed, or represents that its use would not infringe privately owned rights. Reference herein to any specific commercial product, process, or service by trade name, trademark, manufacturer, or otherwise does not necessarily constitute or imply its endorsement, recommendation, or favoring by the United States Government or any agency thereof. The views and opinions of authors expressed herein do not necessarily state or reflect those of the United States Government or any agency thereof.

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In Search Of A Meaningful Field-error Specification For Wigglers

Cited by 4 publications

References 2 publications

Shaping Photon Beams with Undulators and Wigglers

Shaping Photon Beams with Undulators and Wigglers

Using Artificial Immune Systems to Sort and Shim Insertion Devices at Diamond Light Source

Reduction of FEL gain due to wiggler errors

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