| Paper | Title | Page |
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| WEP015 | Electro-Optical Bunch Length Detection at the European XFEL | 360 |
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| The electro-optical bunch length detection system based on electro-optic spectral decoding has been installed and is being commissioned at the European XFEL. The system is capable of recording individual longitudinal bunch profiles with sub-picosecond resolution at a bunch repetition rate of 1.13MHz . Bunch lengths and arrival times of entire bunch trains with single-bunch resolution have been measured as well as jitter and drifts for consecutive bunch trains. In addition, we are testing a second electro-optical detection strategy, the so-called photonic time-stretching, which consists of imprinting the electric field of the bunch onto a chirped laser pulse, and then "stretching" the output pulse by optical means. As a result, we obtain is a slowed down "optical replica" of the bunch shape, which can be recorded using a photodiode and GHz-range acquisition. These tests are performed in parallel with the existing spectral decoding technique based on a spectrometer in order to allow a comparative study. In this paper, we present first results for both detection strategies from electron bunches after the second bunch compressor of the European XFEL. | ||
| DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-FEL2019-WEP015 | |
| About • | paper received ※ 24 August 2019 paper accepted ※ 28 August 2019 issue date ※ 05 November 2019 | |
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| THP048 | Progress Towards Laser Plasma Electron Based Free Electron Laser on COXINEL | 684 |
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Laser plasma acceleration (LPA) with up to several GeV beam in very short distance appears very promising. The Free Electron Laser (FEL), though very challenging, can be viewed as a qualifying application of these new emerging LPAs. The energy spread and divergence, larger than from conventional accelerators used for FEL, have to be manipulated to fulfil the FEL requirements. On the test experiment COXINEL (ERC340015), the beam is controlled in a manipulation [1,2] line, using permanent magnet quadrupoles of variable strength [3] for emittance handing and a decompression chicane equipped with a slit for the energy selection, enabling FEL amplification for baseline reference parameters [2]. The electron position and dispersion are independently adjusted [4]. The measured spontaneous emission radiated by a 2 m long 18 mm period cryo-ready undulator exhibits the typical undulator spatio-spectral pattern, in agreement with the modelling of the electron beam travelling along the line and of the afferent photon generation. The wavelength is easily tuned with undulator gap variation. A wavelength stability of 2.6% is achieved. The undulator linewidth can be controlled.
[1] A. Loulergue et al., New J. Phys. 17 023028 (2015) [2] M. E. Couprie et al., PPCF 58, 3 (2016) [3] F. Marteau et al., APL 111, 253503 (2017) [4] T. André et al., Nature Comm. 1334 (2018) |
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| DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-FEL2019-THP048 | |
| About • | paper received ※ 13 August 2019 paper accepted ※ 16 September 2019 issue date ※ 05 November 2019 | |
| Export • | reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml) | |