Temporal Characterization of Femtosecond Laser-Plasma-Accelerated Electron Bunches Using Terahertz Radiation

Tilborg, J. van; Schroeder, C. B.; Filip, C.; Tóth, Cs.; Geddes, C. G. R.; Fubiani, G.; Huber, Rupert; Kaindl, Robert A.; Esarey, E.; Leemans, Wim

doi:10.1103/physrevlett.96.014801

Cited by 183 publications

(137 citation statements)

References 38 publications

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“…Bunch profile generated using the results from the X-FROG retrieval algorithm and inverting Eq. (12). The original 15 fs bunch profile is shown in red and the retrieved pulse is given in blue.…”

Section: Discussionmentioning

confidence: 99%

“…It has been the focus of most ongoing research to obtain thinner and thinner crystals to measure shorter bunches. This leads to reduced signal and does not resolve the ultimate issue, namely the resonance [12,15]. Fortunately, the picture described above is not complete in its treatment of the mixing process that occurs between the self-fields and the optical probe.…”

Section: B Limitationsmentioning

confidence: 98%

“…This is done by inverting Eq. (12) and plugging the retrieved mixed field into it. An example of a retrieved bunch profile is given in Fig.…”

Section: Mixed Field Reconstructionmentioning

confidence: 99%

“…Recently, this has been adapted to the longitudinal profiling of accelerated charged particle beams. EOS has been used to characterize beams either directly, by measuring their self-fields [2][3][4][5][6][7][8][9][10][11], or indirectly by measuring the THz fields generated from transition radiation diagnostics [12,13]. In the case of the former, the particle beam's longitudinal profile can be deduced from its self-fields due to the fact that for sufficiently relativistic beams the temporal structure of the selffields matches the temporal structure of the beam [14].…”

Section: Introductionmentioning

confidence: 99%

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Extending electro-optic detection to ultrashort electron beams

Helle

Gordon

Kaganovich

et al. 2012

Phys. Rev. ST Accel. Beams

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We propose a technique to extend noninvasive electro-optic detection of relativistic electron beams to bunch lengths of ' 10 fs. This is made possible by detecting the frequency mixing that occurs between the optical probe and the space charge fields of the beam, while simultaneously time resolving the resulting mixed frequency signal. The necessary formalism to describe this technique is developed and numerical solutions for various possible experimental conditions are made. These solutions are then compared to simulation results for consistency. Finally, the method to reconstruct the original bunch profile from the proposed diagnostic is discussed and an example showing a 15 fs test beam reconstructed to within an accuracy of 15% is given.

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Section: Discussionmentioning

confidence: 99%

Section: B Limitationsmentioning

confidence: 98%

“…This is done by inverting Eq. (12) and plugging the retrieved mixed field into it. An example of a retrieved bunch profile is given in Fig.…”

Section: Mixed Field Reconstructionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Extending electro-optic detection to ultrashort electron beams

Helle

Gordon

Kaganovich

et al. 2012

Phys. Rev. ST Accel. Beams

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“…Ultrashort relativistic electron bunches are also produced in plasma wakefield accelerators which have made impressive progress in the last years, see [4 -6] and the references quoted therein. Precise knowledge of the temporal profile of the electron bunches is essential for a detailed understanding of the physical processes in all these accelerators [1,4]. Two of the most important current techniques for the single-shot direct visualization of longitudinal electron bunch profiles are transverse-deflecting structures (TDS) and electro-optic (EO) detection.…”

mentioning

confidence: 99%

Benchmarking of Electro-Optic Monitors for Femtosecond Electron Bunches

et al. 2007

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The longitudinal profiles of ultrashort relativistic electron bunches at the soft x-ray free-electron laser FLASH have been investigated using two single-shot detection schemes: an electro-optic (EO) detector measuring the Coulomb field of the bunch and a radio-frequency structure transforming the charge distribution into a transverse streak. A comparison permits an absolute calibration of the EO technique. EO signals as short as 60 fs (rms) have been observed, which is a new record in the EO detection of single electron bunches and close to the limit given by the EO material properties. DOI: 10.1103/PhysRevLett.99.164801 PACS numbers: 41.75.Ht, 41.60.Cr, 41.85.Ew, 42.65.Re Intense relativistic electron bunches with a duration of 100 femtoseconds or less are essential for free-electron lasers (FELs) based on the principle of self-amplified spontaneous emission (SASE), such as the ultraviolet and soft x-ray Free-electron LASer at Hamburg (FLASH) [1], and future x-ray FELs like the Linac Coherent Light Source [2] at SLAC and the European XFEL [3]. Ultrashort relativistic electron bunches are also produced in plasma wakefield accelerators which have made impressive progress in the last years, see [4 -6] and the references quoted therein. Precise knowledge of the temporal profile of the electron bunches is essential for a detailed understanding of the physical processes in all these accelerators [1,4]. Two of the most important current techniques for the single-shot direct visualization of longitudinal electron bunch profiles are transverse-deflecting structures (TDS) and electro-optic (EO) detection.The principle of the TDS was demonstrated in 1964 [7]: the temporal profile of the electron bunch charge density is transferred to a transverse streak on a view screen by a rapidly varying electromagnetic field, analogous to the sawtooth voltage in a conventional oscilloscope tube. The time resolution of the TDS installed at FLASH can reach 15 fs (rms) if the beam optics is optimized to yield the smallest possible beam spot on the view screen [8]. With the optics tuned for FEL operation, the resolution is about 20 fs. Thus, the diagnostic itself is part of the accelerator optics design. The TDS must be several meters long to achieve sufficient streak length, preventing its use in a plasma wakefield accelerator. Furthermore, it is inherently destructive, prohibiting the characterization of bunches that are needed further downstream.The EO effect has been used extensively in terahertz time domain spectroscopy for over a decade [9], but its exploitation in electron bunch diagnostics is more recent. The need for an absolute temporal signal, rather than just a relative change, which is sufficient in spectroscopic applications, is a uniquely demanding requirement of EO bunch diagnostics. Single-shot EO measurements of picosecond electron bunches were first demonstrated in 2002 [10]. Several variants of EO bunch diagnostics have been applied [10 -12], all sharing the underlying principle of utilizing the field-induced bir...

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