| Paper | Title | Page |
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TUB03 |
Hard X-Ray Self-Seeding at PAL-XFEL | |
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| A hard X-ray self-seeding utilizing time-delayed forward Bragg diffracted photons from thin diamond crystals has been successfully commissioned in a broad spectral range (3.5~14.4 keV), and will be soon provided to user experiments. In the self-seeded mode, the spectral bandwidth is typically 0.2~0.5 eV FWHM in contrast to SASE mode, in which the spectral bandwidth is around 20 eV. This implies that the seeded FEL can be a single longitudinal mode laser since the number of longitudinal mode is 100~200 in the SASE operation. In this case, the photon number of filtered FEL is expected to be fluctuated 100% from the narrow bandwidth filtering out of random and spiky SASE spectra. We found that our energy stability of electron bunches (10-4) do not degrade much the seeding performance and the large variation of the seeded FEL intensity will be from the seeding probability. The advantages of 30 um thin diamond crystal and diagnostic tool for the self-seeding will be also presented. | ||
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Slides TUB03 [28.431 MB] | |
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| TUP064 | Effect on FEL Gain Curve Using Phase Shifters | 203 |
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| Phase matching between FEL and electron beam should be precisely controlled for FEL amplification. Phase shifters located between undulators performs the phase matching. An electron beam can be controlled to be in the in- or out-phase by setting the phase shifters from the phase shifter scan. In this article, we show effects of FEL gain curve by setting the in- and out-phase of electron beam. We address reasons of the reduction of FEL intensity in the out-phase condition dividing the linear and saturation FEL amplification regimes. In the linear regime the gain curve is shifted, and in the saturation regime the electron loss occurs during the undulator tapering. Our results show agreements with experiments performed at PAL-XFEL. | ||
| DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-FEL2019-TUP064 | |
| About • | paper received ※ 21 August 2019 paper accepted ※ 28 August 2019 issue date ※ 05 November 2019 | |
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| THP051 | Generating Trains of Attosecond Pulses with a Free-Electron Laser | 692 |
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| Recently, a Hard X-ray Self-Seeding setup was commissioned at PAL XFEL. Its main purpose is to increase the temporal coherence of FEL radiation in an active way. We report another application of this setup to generate trains of short sub-femtosecond pulses with linked phases. We discuss preliminary results of both experiment and corresponding simulations as well as indirect diagnostics of the radiation properties. | ||
| DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-FEL2019-THP051 | |
| About • | paper received ※ 20 August 2019 paper accepted ※ 27 August 2019 issue date ※ 05 November 2019 | |
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