Measurement of the X-ray Spectrum of a Free Electron Laser with a Wide-Range High-Resolution Single-Shot Spectrometer

Inubushi, Yuichi; Inoue, Ituro; Kim, Jang Woo; Nishihara, Akihiko; Matsuyama, Satoshi; Yumoto, Hirokatsu; Koyama, Takahisa; Tono, Kensuke; Ohashi, Haruhiko; Yamauchi, Kazuto; Yabashi, Makina

doi:10.3390/app7060584

Cited by 35 publications

(28 citation statements)

References 18 publications

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“…The experiment was conducted at SACLA BL3 under the following conditions: photon energy of 9.1 keV, pulse energy of approximately 11 mJ at focus, and an estimated pulse duration of 7 fs (Inubushi et al, 2012(Inubushi et al, 2017. Based on previous studies (Kim et al, 2015), the power density of the XFEL beams on our mirrors was much lower than the damage threshold.…”

Section: Methodsmentioning

confidence: 99%

Generation of an X-ray nanobeam of a free-electron laser using reflective optics with speckle interferometry

Inoue¹,

Matsuyama²,

Yamada³

et al. 2020

J Synchrotron Radiat

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Ultimate focusing of an X-ray free-electron laser (XFEL) enables the generation of ultrahigh-intensity X-ray pulses. Although sub-10 nm focusing has already been achieved using synchrotron light sources, the sub-10 nm focusing of XFEL beams remains difficult mainly because the insufficient stability of the light source hinders the evaluation of a focused beam profile. This problem is specifically disadvantageous for the Kirkpatrick–Baez (KB) mirror focusing system, in which a slight misalignment of ∼300 nrad can degrade the focused beam. In this work, an X-ray nanobeam of a free-electron laser was generated using reflective KB focusing optics combined with speckle interferometry. The speckle profiles generated by 2 nm platinum particles were systematically investigated on a single-shot basis by changing the alignment of the multilayer KB mirror system installed at the SPring-8 Angstrom Compact Free-Electron Laser, in combination with computer simulations. It was verified that the KB mirror alignments were optimized with the required accuracy, and a focused vertical beam of 5.8 nm (±1.2 nm) was achieved after optimization. The speckle interferometry reported in this study is expected to be an effective tool for optimizing the alignment of nano-focusing systems and for generating an unprecedented intensity of up to 1022 W cm−2 using XFEL sources.

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Section: Methodsmentioning

confidence: 99%

Generation of an X-ray nanobeam of a free-electron laser using reflective optics with speckle interferometry

Inoue¹,

Matsuyama²,

Yamada³

et al. 2020

J Synchrotron Radiat

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“…The experiment was performed on BL3 at SACLA at 10 keV, for which the pulse duration has been estimated to be $8 fs full width at half-maximum (FWHM) from spectra measured with a wide-range high-resolution spectrometer (Inubushi et al, 2017). The pulse energy of each delay branch was 0.18 mJ on average for an incident pulse energy of 7 mJ after the Si(111) double-crystal monochromator.…”

Section: Methodsmentioning

confidence: 99%

Characterization of temporal coherence of hard X-ray free-electron laser pulses with single-shot interferograms

Osaka

Hirano

Morioka

et al. 2017

Int Union Crystallogr J

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Temporal coherence is one of the most fundamental characteristics of light, connecting to spectral information through the Fourier transform relationship between time and frequency. Interferometers with a variable path-length difference (PLD) between the two branches have widely been employed to characterize temporal coherence properties for broad spectral regimes. Hard X-ray interferometers reported previously, however, have strict limitations in their operational photon energies, due to the specific optical layouts utilized to satisfy the stringent requirement for extreme stability of the PLD at sub-å ngströ m scales. The work presented here characterizes the temporal coherence of hard X-ray free-electron laser (XFEL) pulses by capturing single-shot interferograms. Since the stability requirement is drastically relieved with this approach, it was possible to build a versatile hard X-ray interferometer composed of six separate optical elements to cover a wide photon energy range from 6.5 to 11.5 keV while providing a large variable delay time of up to 47 ps at 10 keV. A high visibility of up to 0.55 was observed at a photon energy of 10 keV. The visibility measurement as a function of time delay reveals a mean coherence time of 5.9 AE 0.7 fs, which agrees with that expected from the single-shot spectral information. This is the first result of characterizing the temporal coherence of XFEL pulses in the hard X-ray regime and is an important milestone towards ultra-high energy resolutions at micro-electronvolt levels in time-domain X-ray spectroscopy, which will open up new opportunities for revealing dynamic properties in diverse systems on timescales from femtoseconds to nanoseconds, associated with fluctuations from å ngströ m to nanometre spatial scales.

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“…At BL3, XFEL pulses are normally generated by a self-amplified spontaneous emission (SASE) scheme [18,19]. The photon energy ranges from 4 to 20 keV with a pulse duration of around 8 fs in full width at half maximum (FWHM) in horizontal polarization [12,13]. The bandwidth (∆E/E) can be selected from two operation modes: a pink and monochromatic beam.…”

Section: Xfel and Focusing Opticsmentioning

confidence: 99%

“…In contrast, single-shot measurement is applicable with an XFEL sources owing to plenty photon numbers included in a single XFEL pulse. Moreover, the short pulse duration enables to obtain a snapshot with the time resolution better than 10 fs [12,13]. Therefore, instantaneous ultrahigh-pressure states generated with high-power laser irradiation can be investigated with XFEL.…”

Section: Introductionmentioning

confidence: 99%

Development of an Experimental Platform for Combinative Use of an XFEL and a High-Power Nanosecond Laser

et al. 2020

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We developed an experimental platform for combinative use of an X-ray free electron laser (XFEL) and a high-power nanosecond laser. The main target of the platform is an investigation of matter under high-pressure states produced by a laser-shock compression. In this paper, we show details of the experimental platform, including XFEL parameters and the focusing optics, the laser irradiation system and X-ray diagnostics. As a demonstration of the high-power laser-pump XFEL-probe experiment, we performed an X-ray diffraction measurement. An in-situ single-shot X-ray diffraction pattern expands to a large angle side, which shows a corundum was compressed by laser irradiation.

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Measurement of the X-ray Spectrum of a Free Electron Laser with a Wide-Range High-Resolution Single-Shot Spectrometer

Cited by 35 publications

References 18 publications

Generation of an X-ray nanobeam of a free-electron laser using reflective optics with speckle interferometry

Generation of an X-ray nanobeam of a free-electron laser using reflective optics with speckle interferometry

Characterization of temporal coherence of hard X-ray free-electron laser pulses with single-shot interferograms

Development of an Experimental Platform for Combinative Use of an XFEL and a High-Power Nanosecond Laser

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