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@PHDTHESIS{Bohlen:453194,
      author       = {Bohlen, Simon},
      othercontributors = {Osterhoff, Jens and Foster, Brian},
      title        = {{M}easurement of {E}lectron {P}arameters using {T}homson
                      {S}cattering},
      school       = {Universtät Hamburg},
      type         = {Dissertation},
      address      = {Hamburg},
      publisher    = {Verlag Deutsches Elektronen-Synchrotron},
      reportid     = {PUBDB-2020-05030, DESY-THESIS-2021-009},
      series       = {DESY-THESIS},
      pages        = {158},
      year         = {2021},
      note         = {Dissertation, Universtät Hamburg, 2020},
      abstract     = {Laser-plasma acceleration (LPA) [1] oers acceleration
                      gradients several orders of magnitudehigher than in
                      conventional radio-frequency accelerators, enabling the
                      accelerationof electrons to hundreds of MeV in just a few
                      millimetres. These small-scale acceleratorsand in particular
                      X-rays generated from LPA electron beams could potentially
                      be used inmaterial science or medicine [2]. However, LPAs
                      are not commercially used yet, partlybecause repetition rate
                      and shot-to-shot beam stability are not sucient for
                      industrial ormedical applications and the investigation of
                      the long-term stability on the order of severalhours
                      required for the industrial use of LPA has only just started
                      [3, 4].In this thesis, an electron source was developed to
                      match parameters required for theuse of LPA in X-ray
                      uorescence imaging experiments [5-7]. To generate stable
                      electronbeams, self-truncated ionisation injection using a
                      weakly relativistic laser was experimentallyimplemented for
                      the rst time [8]. The long-term stability of these beams
                      wasinvestigated in an 8 hour run at a repetition rate of 2:5
                      Hz, resulting in a total of 72000acceleration events. During
                      this time, the average charge stayed constant while the
                      meanenergy decreased by 7 percent, showing the necessity to
                      further investigate long-term stabilityLPA, as such a drift
                      would likely not have been detectable from the only tens
                      tohundreds of shots that are usually considered.Furthermore,
                      a new diagnostic technique based on Thomson scattering [9]
                      was developed,which oers the rst in-situ measurement of
                      electron parameters during the accelerationinside the
                      wakeeld. Using this technique, the electron-energy evolution
                      wasmeasured inside the plasma, showing an energy increase
                      from 35MeV to 61MeV over adistance of 400 µm. The results
                      agree well with particle-in-cell simulations and were usedto
                      study the dephasing of the electron bunch inside the
                      accelerator. By combining measurementsand simulations, the
                      inuence of the laser strength parameter on the
                      dephasinglength could be isolated, showing the power of this
                      method.This newly developed diagnostic technique could be
                      transferred to other electron parameterssuch as divergence
                      or emittance [10-12] to obtain a full picture of the
                      electronbunch during acceleration. This could help to study
                      experimentally issues of LPA such asemittance growth and
                      increase the stability of electron beams from plasma
                      accelerators.In combination with further long-term stability
                      studies, these measurements could helpto transfer LPA from
                      proof-of-principle experiments to X-ray sources for a broad
                      range ofapplications.},
      cin          = {FLA / MPA},
      cid          = {I:(DE-H253)FLA-20120731 / I:(DE-H253)MPA-20200816},
      pnm          = {621 - Accelerator Research and Development (POF4-621) /
                      PHGS, VH-GS-500 - PIER Helmholtz Graduate School
                      $(2015_IFV-VH-GS-500)$},
      pid          = {G:(DE-HGF)POF4-621 / $G:(DE-HGF)2015_IFV-VH-GS-500$},
      experiment   = {EXP:(DE-H253)FLASHForward-20150101},
      typ          = {PUB:(DE-HGF)3 / PUB:(DE-HGF)11},
      doi          = {10.3204/PUBDB-2020-05030},
      url          = {https://bib-pubdb1.desy.de/record/453194},
}