Home > Research > Publications & Outputs > Power and spectral evolution of a Free Electron...

Electronic data

  • NIMA EA-FELo___06_04_2021

    Rights statement: This is the author’s version of a work that was accepted for publication in Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment. Changes resulting from the publishing process, such as peer review, editing, corrections, structural formatting, and other quality control mechanisms may not be reflected in this document. Changes may have been made to this work since it was submitted for publication. A definitive version was subsequently published in Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, ?-?, ?, 2021 DOI: 10.1016/j.nima.2021.165376

    Accepted author manuscript, 1.38 MB, PDF document

    Embargo ends: 22/04/22

    Available under license: CC BY-NC-ND

Links

Text available via DOI:

View graph of relations

Power and spectral evolution of a Free Electron Laser oscillator with electron beam energy ramping

Research output: Contribution to journalJournal articlepeer-review

Published
Close
Article number165376
<mark>Journal publication date</mark>11/07/2021
<mark>Journal</mark>Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment
Volume1004
Number of pages12
Publication StatusPublished
Early online date22/04/21
<mark>Original language</mark>English

Abstract

This work is focused on experiments showing enhancements in power extraction efficiency and spectral control of a W-band Free Electron Laser oscillator (FELo) using ramping of the electron beam energy. The FELo operates at 1.4 MeV with electron beam currents of 1–2 A with pulse duration 10–20 μs. Changing the beam energy post-laser-saturation of the initially unbunched continuous electron beam changes the phase-space oscillation trajectory between the beam energy and trapping ponderomotive wave. This enables very significant increases in output power with just 2% changes in beam energy, cases of 39%, and 100% are presented. Unlike in previous work a variable delay has been introduced between the start of the electron beam and the ramp in electron beam energy such that the effect can be observed unambiguously despite significant system jitter from shot-to-shot. In addition to increasing radiative efficiency, where desirable this could be used to rapidly modulate the power without a need to modify parameters such as the beam current or resonator out-coupling. This effect is shown to pull the locked longitudinal modes up or down depending on the direction of the ramp allowing fine frequency control and influence over mode-competition and mode-hops. To complement the experiments simulations were run to map the full range of beam-energy-ramping against resonator out-coupling and beam current for the experimental system.

Bibliographic note

This is the author’s version of a work that was accepted for publication in Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment. Changes resulting from the publishing process, such as peer review, editing, corrections, structural formatting, and other quality control mechanisms may not be reflected in this document. Changes may have been made to this work since it was submitted for publication. A definitive version was subsequently published in Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, ?-?, ?, 2021 DOI: 10.1016/j.nima.2021.165376