# Study of the Radiation Field From a Hollow Electron Beam Inside an Infrared Free Electron Laser Oscillator

28 Aug 2022-pp 1-2

TL;DR: In this article , the authors considered the operation of an IR free electron laser (FEL) oscillator with a hollow beam and analyzed its effect on FEL performance, and showed that using a hollow electron beam could offer a higher saturated power than use of a Gaussian electron beam.

Abstract: At University of Science and Technology of China, we have an Infrared (IR) free electron laser (FEL) oscillator experimental facility (FELiChEM) to generate radiations in the wavelength range of 2.5-50 m and 40-200 m. The output power is one of the most concerned parameters by the users. Since the electron beam distribution and the out-coupling hole in the resonator mirror can influence the saturated power and the optical mode, it would be an important issue to the output power of the IR light source. It has been demonstrated that use of a hollow electron beam could offer a higher saturated power than use of a Gaussian electron beam. Thus we consider the operation of FELiChEM with a hollow beam, and analyze its effect on FEL performance.

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18 Aug 2000

TL;DR: ELEGANT (ELEctron Generation ANd Tracking) as discussed by the authors is the principle accelerator simulation code used at the Advanced Photon Source (APS) for circular and one-pass machines.

Abstract: ELEGANT (ELEctron Generation ANd Tracking) is the principle accelerator simulation code used at the Advanced Photon Source (APS) for circular and one-pass machines. Capabilities include 6-D tracking using matrices up to third order, canonical integration, and numerical integration. Standard beamline elements are supported, as well as coherent synchrotron radiation, wakefields, rf elements, kickers, apertures, scattering, and more. In addition to tracking with and without errors, ELEGANT performs optimization of tracked properties, as well as computation and optimization of Twiss parameters, radiation integrals, matrices, and floor coordinates. Orbit/trajectory, tune, and chromaticity correction are supported. ELEGANT is fully compliant with the Self Describing Data Sets (SDDS) file protocol, and hence uses the SDDS Toolkit for pre- and post-processing. This permits users to prepare scripts to run the code in a flexible and automated fashion. It is particularly well suited to multistage simulation and concurrent simulation on many workstations. Several examples of complex projects performed with ELEGANT are given, including top-up safety analysis of the APS and design of the APS bunch compressor.

894 citations

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01 Jun 1999-Nuclear Instruments & Methods in Physics Research Section A-accelerators Spectrometers Detectors and Associated Equipment

TL;DR: The GENESIS 1.3 simulation code as discussed by the authors uses a fully three-dimensional representation of the FEL equations in the paraxial approximation for time-dependent and steady-state simulations of single-pass FEL.

Abstract: Numerical simulation codes are basic tools for designing Free Electron Lasers (FEL). They are used to study the impact of different parameters, e.g. wiggler errors and external focusing, which allow FEL users to optimize the performance. For faster execution some simulation codes assume radial symmetry or decompose the radiation field into a few azimuthal modes, although then this treatment does not include the full description of the FEL. This contribution describes the new FEL code GENESIS 1.3 which uses a fully three-dimensional representation of the FEL equations in the paraxial approximation for time-dependent and steady-state simulations of single-pass FEL. In particular this approach is suitable for cases where the radial symmetry is broken by the electron beam distribution as well as by wiggler errors, betatron motion and off axis injection of the electron beam. The results, presented here, are based on the parameters of the TESLA Test Facility FEL at DESY.

758 citations

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TL;DR: In this paper, a new electron beam injection gun was developed to produce pulsed relativistic electron beams with a power of 1010 W. The annular shaped beam propagates in a magnetic field with efficiencies approaching 100% and its radius may be controlled by the magnetic field configuration.

Abstract: A new electron beam injection gun has been developed to produce pulsed relativistic electron beams with a power of 1010 W. The annular shaped beam propagates in a magnetic field with efficiencies approaching 100% and its radius may be controlled by the magnetic field configuration.

73 citations

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28 Aug 2006

TL;DR: A paraxial Optical Propagation Code (OPC) based on the Spectral Method and Fresnel Diffraction Integral is presented, which in combination with Genesis 1.3 can be used to perform either steady-state or time-dependent FEL oscillator simulations.

Abstract: Modeling free-electron laser (FEL) oscillators requires calculation of both the light-beam interaction within the undulator and the propagation of the light outside the undulator. We present a paraxial Optical Propagation Code (OPC) based on the Spectral Method and Fresnel Diffraction Integral, which in combination with Genesis 1.3 can be used to perform either steady-state or time-dependent FEL oscillator simulations. A flexible scripting interface is used both to describe the optical resonator and to control the codes for propagation and amplification. OPC enables modeling of complex resonator designs that may include hard-edge elements (apertures) or hole-coupled mirrors with arbitrary
shapes. Some capabilities of OPC are illustrated using the FELIX system as an example.

13 citations

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11 Jun 1996-Nuclear Instruments & Methods in Physics Research Section A-accelerators Spectrometers Detectors and Associated Equipment

TL;DR: In this paper, a nonlinear analysis of an annular beam FEL with a helical wiggler and axial guide field is presented, and the ARACHNE slow-time-scale simulation code shows that efficiencies of 10%, corresponding to gains >40 dB, are possible for grazing incidence with the TE11 cylindrical waveguide mode in Ku-band.

Abstract: A nonlinear analysis of an annular beam FEL with a helical wiggler and axial guide field is presented. An annular beam has the advantage of reduced DC self-fields, facilitating beam transport in short period wigglers. A 55 kV/5 A annular beam interacting with the TE11 cylindrical waveguide mode is considered. The inner and outer beam radii are 0.27 and 0.33 cm, respectively. The wiggler amplitude is 250 G and the period is 0.9 cm. Axial guide fields up to 3 kG are studied. The ARACHNE slow-time-scale simulation code shows that efficiencies of 10%, corresponding to gains >40 dB, are possible for grazing incidence with the TE11 mode in Ku-band. In addition, the 3 dB instantaneous bandwidth is found to be greater than 20%.

4 citations