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THIBNO02 |
Demonstration Of Two-color XFEL Operation and Autocorrelation Measurement at SACLA | |
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| Recently two-color XFEL operation with a relative wavelength separation of 30 % has been achieved at SACLA in hard x-rays. In the two-color operation at SACLA, a simple and lucid scheme is employed, namely the first and second halves of the undulators are set at different K values. To make a time delay between the two-color photon pulses, a magnetic chicane is installed between the two undulator sections to detour the electron beam. Since the two-color pulses are emitted from the same electron bunch, there is no time jitter and the delay can be finely adjusted up to 40 fs. Two wavelengths can be freely selected in hard x-rays. The photon pulse length of the single-color operation measured by an autocorrelation technique is less than 10 fs (FWHM). The two-color operation of SACLA, which provides femtoseconds-short pulses with a GW-level peak power, is an ideal light source for x-ray pump x-ray probe experiments. | ||
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Slides THIBNO02 [1.988 MB] | |
| THOANO01 | Stable Operation of HHG-Seeded EUV-FEL at the SCSS Test Accelerator | 728 |
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| We performed the higher-order harmonic (HH) seeded FEL operation at a 61.2 nm fundamental wavelength, using a seeding source of HH pulses from a Ti:sapphire laser at the SCSS (EUV-FEL) accelerator. It is important for the HH seeded FEL scheme to synchronize the seeding laser pulses to the electron bunches. We constructed the relative arrival timing monitor based on Electro-Optic sampling (EOS). Since the EOS-probe laser pulses were optically split from HH-driving laser pulses, the arrival time difference of the seeding laser pulses, with respect to the electron bunches, were measured bunch-by-bunch. This non-invasive EOS monitor made uninterrupted, real-time monitoring possible even during the seeded FEL operation. The EOS system was used for the arrival timing feedback with a few-hundred-femtosecond adjustability for continual operation of the HH-seeded FEL. By using the EOS-locking system, the HH seeded FEL was operated over half a day with a 20-30% hit rate. The output pulse energy reached 20uJ at the 61.2 nm wavelength. A user experiment was performed by using the seeded EUV-EL and a clear difference between the SASE-FEL and the seeded FEL was observed. | ||
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Slides THOANO01 [11.493 MB] | |