First lasing of LEBRA FEL at Nihon University at a wavelength of 1.5

Hayakawa, Yasushi; Sato, Iwao; Hayakawa, Katsumi; Tanaka, Toshinari; Nakazawa, Hiroyuki; Yokoyama, K.; Kanno, Kyoko; Sakai, Takeshi; Ishiwata, Kiichi; Enomoto, Atsushi; Fukuda, Shigeki; Ohsawa, S.; Tsuchiya, K.; Kato, Masashi

doi:10.1016/s0168-9002(02)00281-4

Cited by 31 publications

(9 citation statements)

References 2 publications

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“…As shown in Fig. 1a, the electron beam from the linac is supplied to two straight sections and used in each straight section for wavelength-tunable monochromatic light sources, namely an www.nature.com/scientificreports/ infrared FEL and a parametric X ray 12,13 . As described in the Method section, a coupler device that can extract the CER beam generated at the downstream bending magnet without losing the FEL beam was installed in the optical cavity 8 .…”

Section: Resultsmentioning

confidence: 99%

Observation of terahertz coherent edge radiation amplified by infrared free-electron laser oscillations

Sei

Sakai

Hayakawa

et al. 2021

Sci Rep

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A coupling device, which can extract coherent edge radiation (CER) from an optical cavity for a free-electron laser (FEL) without damaging the FEL due to diffraction loss, was developed at Nihon University. We successfully observed the CER beam with a power of 1 mW or more in the terahertz range during FEL oscillation. It is revealed that the CER power changed with the detuning of the optical cavity and the dependence of the CER power on the detuning length differs from that of the FEL power. The measured CER spectra indicate that the longitudinal electron distribution in a bunch is modulated by the FEL oscillation with a period corresponding to the FEL slippage length. We herein report the characteristics of the CER with FEL oscillation in detail. These results demonstrate that the CER is excellent tool to reveal the overall effect of FEL interaction on electron distribution in a bunch.

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Section: Resultsmentioning

confidence: 99%

Observation of terahertz coherent edge radiation amplified by infrared free-electron laser oscillations

Sei

Sakai

Hayakawa

et al. 2021

Sci Rep

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“…An IR-FEL system at Kyoto University named KU-FEL was used for mid-infrared radiation [28], and the laser system at LEBRA of Nihon University was used for nearinfrared radiation [29,30]. An electron beam is provided by an electron-linear accelerator, and the IR-FEL can be produced by the interaction between the synchrotron radiation stored in an optical resonator and the electron beam in the undulator.…”

Section: Infrared Free Electron Laser Irradiationmentioning

confidence: 99%

Degradation of Lignin by Infrared Free Electron Laser

et al. 2022

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Lignin monomers have attracted attention as functional materials for various industrial uses. However, it is challenging to obtain these monomers by degrading polymerized lignin due to the rigid ether linkage between the aromatic rings. Here, we propose a novel approach based on molecular vibrational excitation using infrared free electron laser (IR-FEL) for the degradation of lignin. The IR-FEL is an accelerator-based pico-second pulse laser, and commercially available powdered lignin was irradiated by the IR-FEL under atmospheric conditions. Synchrotron-radiation infrared microspectroscopy analysis showed that the absorption intensities at 1050 cm−1, 1140 cm−1, and 3400 cm−1 were largely decreased alongside decolorization. Electrospray ionization mass chromatography analysis showed that coumaryl alcohol was more abundant and a mass peak corresponding to hydrated coniferyl alcohol was detected after irradiation at 2.9 μm (νO-H) compared to the original lignin. Interestingly, a mass peak corresponding to vanillic acid appeared after irradiation at 7.1 μm (νC=C and νC-C), which was supported by our two-dimensional nuclear magnetic resonance spectroscopy analysis. Therefore, it seems that partial depolymerization of lignin can be induced by IR-FEL irradiation in a wavelength-dependent manner.

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“…During full-bunch mode operation, bunches are aligned to produce a peak current of 200 mA and bunch intervals of 350 ps (Figure 2a). During burst-mode operation, it is possible to produce one (single-bunch mode) or two micro-pulses (two-bunch mode) within an interval of 600 ps at a peak current of about 2 A, depending on the operation acceleration frequency and high-speed grid pulse timing ( Figure 2b) and Figure 3) [19][20][21][22]. The experiments conducted in this study carry out the burst-mode operation in two-bunch mode.…”

Section: Coherent Synchrotron Radiation Source At Lebramentioning

confidence: 99%

“…Given these circumstances, we conducted measurements of bunch length using CSR that was capable of non-destructively observing electron beams. As the light source, we utilized the CSR source in the terahertz band that had been developed at the LEBRA accelerator facility at Nihon University [17][18][19][20][21]. Such bunch length measurements obtained using coherent radiation produced by electron bunches have also been studied and used in several accelerator facilities [12][13][14][15][16].…”

Section: Introductionmentioning

confidence: 99%

Evaluation of Bunch Length by Measuring Coherent Synchrotron Radiation with a Narrow-Band Detector at LEBRA

et al. 2020

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This study presents a novel technology to measure electron bunch length with a high time resolution by measuring coherent synchrotron radiation using a narrow-band detector at Laboratory for Electron Beam Research and Application (LEBRA)—an S-band linear accelerator facility for free-electron lasers. The form factor was observed to decrease exponentially with charge—in concordance with the relationship between the intensity of the coherent synchrotron radiation and the magnitude of electron bunch charge—in the region in which the effect of electron bunch charge on bunch length is negligible. The calculated root-mean-square bunch length was observed to agree well with the value determined from the spectral shape obtained. The aforementioned results are expected to be useful in real-time observation of small changes in electron bunches in advanced accelerators.

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First lasing of LEBRA FEL at Nihon University at a wavelength of 1.5

Cited by 31 publications

References 2 publications

Observation of terahertz coherent edge radiation amplified by infrared free-electron laser oscillations

Observation of terahertz coherent edge radiation amplified by infrared free-electron laser oscillations

Degradation of Lignin by Infrared Free Electron Laser

Evaluation of Bunch Length by Measuring Coherent Synchrotron Radiation with a Narrow-Band Detector at LEBRA

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