Location via proxy:   [ UP ]  
[Report a bug]   [Manage cookies]                
  • Open Access

All-optical source size and emittance measurements of laser-accelerated electron beams

F. C. Salgado, A. Kozan, D. Seipt, D. Hollatz, P. Hilz, M. Kaluza, A. Sävert, A. Seidel, D. Ullmann, Y. Zhao, and M. Zepf
Phys. Rev. Accel. Beams 27, 052803 – Published 20 May 2024
PDFHTMLExport Citation
Abstract
Authors
Article Text
  • INTRODUCTION
  • THEORY
  • EXPERIMENTAL SETUP
  • EXPERIMENTAL RESULTS AND DISCUSSIONS
  • CONCLUSIONS
  • ACKNOWLEDGMENTS
  • APPENDICES
    • References

    Abstract

    Novel schemes for generating ultralow emittance electron beams have been developed in past years and promise compact particle sources with excellent beam quality suitable for future high-energy physics experiments and free-electron lasers. Recent theoretical work has proposed a laser-based method capable of resolving emittances in the sub 0.1 mm mrad regime by modulating the electron phase space ponderomotively. Here we present the first experimental demonstration of this scheme using a laser wakefield accelerator. The observed emittance and source size are consistent with published values. We also show calculations demonstrating that tight bounds on the upper limit for emittance and source size can be derived from the “laser-grating” method even in the presence of low signal to noise and uncertainty in laser-grating parameters.

    • Figure
    • Figure
    • Figure
    • Figure
    • Figure
    • Figure
    • Figure
    6 More
    • Received 22 December 2023
    • Accepted 1 May 2024

    DOI:https://doi.org/10.1103/PhysRevAccelBeams.27.052803

    Published by the American Physical Society under the terms of the Creative Commons Attribution 4.0 International license. Further distribution of this work must maintain attribution to the author(s) and the published article’s title, journal citation, and DOI.

    Published by the American Physical Society

    Physics Subject Headings (PhySH)

    1. Research Areas
    Beam diagnostics
    Accelerators & Beams

    Authors & Affiliations

    F. C. Salgado1,2,3,*, A. Kozan1,2,3, D. Seipt1,2,3, D. Hollatz1,2,3, P. Hilz1,2,3, M. Kaluza1,2,3, A. Sävert1,2,3, A. Seidel1,2,3, D. Ullmann1,2,3, Y. Zhao1,2,3, and M. Zepf1,2,3

    • 1Institute of Optics and Quantum Electronics, Friedrich-Schiller-Universität, Max-Wien-Platz 1, 07743 Jena, Germany
    • 2Helmholtz-Institut Jena, Fröbelstieg 3, 07743 Jena, Germany
    • 3GSI Helmholtzzentrum für Schwerionenforschung, Planckstraße 1, 64291 Darmstadt, Germany

    • *felipe.salgado@uni-jena.de

    Article Text

    Click to Expand

    References

    Click to Expand
    Issue

    Vol. 27, Iss. 5 — May 2024

    Reuse & Permissions
    Author publication services for translation and copyediting assistance advertisement

    Authorization Required

    Log In
    Other Options
    ×

    Images

    • Figure 1
      Figure 1

      Comparison between the phase-space distributions n(x,px) of the electron beam directly before (left) and after (right) its interaction with the laser interference pattern with intensity of κ=1 and wave vector of kG=0.8/μm. The initial electron beam parameters used for this simulation were as follows: σx=2  μm and σp/mec=2, and L=10  μm yielding in a ratio σx/λG≈0.25. Blue curves show the integrated momentum distributions N(px). The maxpx and minpx of F(px,α) used for estimating the RT ratio as given in Eq. (11) are shown in the modulated signal in the left panel.

      Reuse & Permissions
    • Figure 2
      Figure 2

      Theoretical calculation of the peak-to-valley ratio R of the modulation as a function of κ for various source sizes σx. The triangle marker represents expected peak-to-valley ratio RT for the simulated modulation in the beam distribution shown in Fig. 1.

      Reuse & Permissions
    • Figure 3
      Figure 3

      Upper panel: grating intensity parameter κ that maximizes the peak-to-valley ratio RT of the modulated electron beam as function of various source sizes (solid red curve). Lower panel: maximum RT achievable for given source size for various κ. In addition to the κ from the upper panel, the purple dashed curves correspond to the case of κ=2, green is for κ=1, and the yellow dotted curve corresponds to κ=0.2. The values of RT at κ=2 and the maximum are extremely close except for very small source sizes.

      Reuse & Permissions
    • Figure 4
      Figure 4

      Influence of the laser grating strength κ on the source size inference for given peak-to-valley ratio RM.

      Reuse & Permissions
    • Figure 5
      Figure 5

      Effects of the background noise on the estimation of the source size of the electron beam calculated for κ=2. When setting B=0, i.e., νB=0, no background noise is present, the apparent source size value is maximum representing an upper limit of its true value.

      Reuse & Permissions
    • Figure 6
      Figure 6

      Experimental layout for laser interference method test. The laser interference pattern was generated by focusing the ring laser beam by an off-axis parabolic mirror (grating OAP). The electron beam (blue) was modulated after the interaction with the laser grating and then propagated to a scintillation screen, which was imaged onto a CCD camera.

      Reuse & Permissions
    • Figure 7
      Figure 7

      Focal spot of the ring laser. An interference pattern with a mean distance between peaks of λG=(4.2±0.1)  μm and peak intensity of ≈1019  W/cm2 is observed. The interference pattern shown here is used to modulate the electron beam transverse phase space for obtaining the source size and emittance of the electron beam.

      Reuse & Permissions
    • Figure 8
      Figure 8

      Electron beam energy spectra taken from three shots with the same experimental settings.

      Reuse & Permissions
    • Figure 9
      Figure 9

      Modulated electron beam due to the interaction with the interference fringes of the ring laser beam at the focus. Left panel: electron beam was imaged with a YAG:Ce scintillation screen and has a mean peak-to-peak distance between the fringes of about (330.1±6.6)  μm. Upper right: enlarged image at the region of interest where the modulations were taken for data analysis. Lower right: integrated peak-to-valley ratio modulation used for the source size analysis using the laser grating method. The divergence in the x direction θx is utilized for inferring the beam waist using the laser-grating method. The vertical divergence, i.e., in the y direction, is denoted as θy.

      Reuse & Permissions
    • Figure 10
      Figure 10

      Histogram transformation of the measured peak-to-valley ratios of 184 shots (gray histogram on bottom axis) into inferred electron beam source size distributions at different grating strengths κ (histograms on left axis). The purple curve and histogram correspond to the absolute upper limit for the inferred σx (see discussion in text), while yellow corresponds to the measured grating strength of κ=0.2.

      Reuse & Permissions
    • Figure 11
      Figure 11

      Simulated effects of different electron beam energy spreads σE/E on the peak-to-valley modulations after interaction with the laser grating. No detectable difference in the modulated signal is observed, indicating that the variation in energy spread does not significantly impact the modulation.

      Reuse & Permissions
    • Figure 12
      Figure 12

      Simulation of the phase (upper panels) and trace (lower panels) spaces for beams of different energy spreads propagating through the same optical grating.

      Reuse & Permissions
    • Figure 13
      Figure 13

      Sketch of the interaction point between the laser grating and the electron beam. This schematic allows to estimate the interaction time between the optical grating and the electron beam.

      Reuse & Permissions
    ×

    Sign up to receive regular email alerts from Physical Review Accelerators and Beams

    Reuse & Permissions

    It is not necessary to obtain permission to reuse this article or its components as it is available under the terms of the Creative Commons Attribution 4.0 International license. This license permits unrestricted use, distribution, and reproduction in any medium, provided attribution to the author(s) and the published article's title, journal citation, and DOI are maintained. Please note that some figures may have been included with permission from other third parties. It is your responsibility to obtain the proper permission from the rights holder directly for these figures.

    ×

    Log In

    Cancel
    ×

    Search

    Article Lookup

    Paste a citation or DOI
    Enter a citation
    ×