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180 results on '"Kinjo, R."'

3. Evaluation of Pulse Duration of the Soft X-ray Free Electron Laser at SACLA BL1 with Single-Shot Spectrometry

Author

Kubota, Y, Inoue, I, Togawa, K, Kinjo, R, Iwayama, H, Inubushi, Y, Owada, S, Tono, K, Tanaka, T, Hara, T, and Harries, James

Abstract

We performed single-shot spectrometry to evaluate the pulse duration of the soft X-ray free electron laser (FEL) at BL1 of SPring-8 Angstrom Compact free electron LAser (SACLA). The soft X-ray FEL beam was focused with a Kirkpatrick-Baez (KB) focusing mirror system and single-shot spectra were measured with a grating and a two dimensional detector. The spike widths of the spectra, which are inversely proportional to the pulse duration, varied when we changed the operation conditions of the accelerator. By comparing the spike widths with a simulation, the pulse duration was evaluated to be less than 100 fs.

Published
2019

4. Determination of the element-specific complex permittivity using a soft x-ray phase modulator

Author

Kubota, Y., primary, Hirata, Y., additional, Miyawaki, J., additional, Yamamoto, S., additional, Akai, H., additional, Hobara, R., additional, Yamamoto, Sh., additional, Yamamoto, K., additional, Someya, T., additional, Takubo, K., additional, Yokoyama, Y., additional, Araki, M., additional, Taguchi, M., additional, Harada, Y., additional, Wadati, H., additional, Tsunoda, M., additional, Kinjo, R., additional, Kagamihata, A., additional, Seike, T., additional, Takeuchi, M., additional, Tanaka, T., additional, Shin, S., additional, and Matsuda, I., additional

Published
2017
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5. Design Study for Direction Variable Compton Scattering Gamma Ray

Author

Kii, T, primary, Omer, M, additional, Negm, H, additional, Choi, Y W, additional, Kinjo, R, additional, Yoshida, K, additional, Konstantin, T, additional, Kimura, N, additional, Ishida, K, additional, Imon, H, additional, Shibata, M, additional, Shimahashi, K, additional, Komai, T, additional, Okumura, K, additional, Zen, H, additional, Masuda, K, additional, Hori, T, additional, and Ohgaki, H, additional

Published
2013
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6. Development of a field measurement system for the Bulk HTSC SAU

Author

Shibata, M, primary, Kinjo, R, additional, Choi, Y W, additional, Omer, M, additional, Negm, H, additional, Konstantin, T, additional, Yoshida, K, additional, Komai, T, additional, Shimahashi, K, additional, Imon, H, additional, Okumura, K, additional, Zen, H, additional, Kii, T, additional, Masuda, K, additional, and Ohgaki, H, additional

Published
2013
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9. Low-Temperature Operation of a Bulk HTSC Staggered Array Undulator

Author

Kii, T., primary, Kinjo, R., additional, Kimura, N., additional, Shibata, M., additional, Bakr, M. A., additional, Choi, Y. W., additional, Omer, M., additional, Yoshida, K., additional, Ishida, K., additional, Komai, T., additional, Shimahashi, K., additional, Sonobe, T., additional, Zen, H., additional, Masuda, K., additional, and Ohgaki, H., additional

Published
2012
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11. Comparison of the Heating Properties of LaB6 and CeB6 Due to the Back Comparison of the Heating Properties of LaB6 and CeB6 Due to the Back

Author

Bakr, Mahmoud, primary, Kinjo, R., additional, Choi, Y. W., additional, Omer, M., additional, Yoshida, K., additional, Ueda, S., additional, Takasaki, M., additional, Ishida, K., additional, Kimura, N., additional, Zen, H., additional, Sonobe, T., additional, Kii, T., additional, Masuda, K., additional, and Ohgaki, H., additional

Published
2011
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12. Back bombardment for dispenser and lanthanum hexaboride cathodes

Author

Bakr, Mahmoud, primary, Kinjo, R., additional, Choi, Y. W., additional, Omer, M., additional, Yoshida, K., additional, Ueda, S., additional, Takasaki, M., additional, Ishida, K., additional, Kimura, N., additional, Sonobe, T., additional, Kii, T., additional, Masuda, K., additional, Ohgaki, H., additional, and Zen, H., additional

Published
2011
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13. Ferroelectric Soft Mode in a SrTiO3 Thin Film Impulsively Driven to the Anharmonic Regime Using Intense Picosecond Terahertz Pulses

Author

Katayama, I., Aoki, H., Takeda, J., Shimosato, H., Ashida, M., Kinjo, R., Kawayama, I., Tonouchi, M., Nagai, M., and Tanaka, K.

Subjects
Condensed Matter::Materials Science
Abstract

The ferroelectric soft mode in a SrTiO3 thin film was impulsively driven to a large amplitude using intense picosecond terahertz pulses. As the terahertz electric field increased, the soft-mode absorption peak exhibited blueshifting and spectral narrowing. A classical anharmonic oscillator model suggests that the induced displacement is comparable to that of the ferroelectric phase transition. The spectral narrowing indicates that the displacement exceeds that induced by any inhomogeneities in the film, demonstrating that the method can be used to explore intrinsic quartic anharmonicity.

Published
2012

16. Concept of a novel tabletop THz FEL amplifier

Author

Kii, T., primary, Higashimura, K., additional, Bakr, M. A., additional, Kinjo, R., additional, Yoshida, K., additional, Ueda, S., additional, Sonobe, T., additional, Masuda, K., additional, and Ohgaki, H., additional

Published
2009
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22. Beam Energy Compensation in a Thermionic RF Gun by Cavity Detuning.

Author

Zen, H., Ku, T., Masuda, K., Kinjo, R., Higashimura, K., Nagasaki, K., and Ohgaki, H.

Subjects
PARTICLE accelerators, ELECTRON optics, ELECTRON beams, PARTICLES (Nuclear physics), PARTICLE beams, CYCLOTRON waves, ELECTRON bombardment conductivity, RECIRCULATING electron accelerators, ELECTRONICS
Abstract

A thermionic RF gun usually suffers from a rapid decrease of electron beam energy caused by a rapid increase of beam current due to the back-bombardment effect. The authors propose a new method named "cavity detuning" to keep the electron beam energy constant. This method detunes the resonant frequency of the gun cavity to a frequency that is lower (by several hundred kilohertz) than the driving frequency. A proof-of-principle experiment was carried out using a 4.5 cell S-band RF gun. The beam energy was successfully kept constant during a macro-pulse duration of 7.5 is using a cavity detuning of -590 kHz, even with a significant current increase from 240 to 660 mA. A numerical simulation was also conducted to evaluate the cathode temperature, the current density on the cathode surface, and the phase stability of the output beam. All results demonstrated that cavity detuning provides an easy and simple way to compensate for the energy decrease in thermionic RF guns. [ABSTRACT FROM AUTHOR]

Published
2009
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23. Investigation of the Effects of MIR-FELIrradiation on the Photoluminescence of Titanium Dioxides.

Author

Sonobe, T., Bakr, M., Yoshida, K., Higashimura, K., Kinjo, R., Hachiya, K., Kii, T., Masuda, K., and Ohgaki, H.

Subjects
TITANIUM dioxide, PHOTOLUMINESCENCE, FREE electron lasers, ELECTRON-phonon interactions, OPTICAL properties
Abstract

A mid-infrared free electron laser (MIR-FEL: 5 μm–20 μm) facility (KU-FEL: Kyoto University Free Electron Laser) has been constructed in Institute of Advanced Energy Kyoto University, and first laser saturation at 13.2 μm was achieved in May 2008. Currently, we have started to develop the application of MIR-FEL in the field of energy and material science. This study aimed at investigating the feasibility for the development of new evaluation technique of electron-phonon interaction in metal oxides by MIR-FEL. A preliminary result of electrical and optical properties of titanium dioxides was presented. [ABSTRACT FROM AUTHOR]

Published
2010
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24. FEL Beamline for Wide Tunable Range and Beam Sharing System at Kyoto University.

Author

Bakr, Mahmoud, Yoshida, K., Higashimura, K., Ueda, S., Kinjo, R., Zen, H., Sonobe, T., Kii, T., Masuda, K., and Ohgaki, H.

Subjects
FREE electron lasers, NUMERICAL analysis, INDUSTRIAL lasers, ENERGY research
Abstract

A mid-infrared free electron laser (MIR-FEL) facility (KU-FEL: Kyoto University Free Electron Laser) has been constructed for developing energy materials in Institute of Advanced Energy (IAE), Kyoto University. The tunable range of KU-FEL was estimated as 5–13.2 μm by numerical calculation to design the MIR-FEL transport line for application purposes. Aiming to increase the number of FEL users with different desires we decided to develop an FEL beam sharing system that is useful for multi-utilization at different end-stations. The transport line and the beam sharing system has been designed and constructed to the user stations. Applications of the MIR-FEL in the renewable energy research at Kyoto University will start as well. [ABSTRACT FROM AUTHOR]

Published
2010
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25. The First Stable Methyl-Substituted Disilene:  Synthesis, Crystal Structure, and Regiospecific MeLi Addition

Author

Ichinohe, M., Kinjo, R., and Sekiguchi, A.

Abstract

The reductive debromination of 3,3-dibromo-1,1,5,5-tetra-tert-butyl-2,4-bis(di-tert-butylmethylsilyl)-1,2,4,5-tetramethylpentasilane, [(tBu2MeSi)2MeSi]2SiBr2 (1), gave (E)-[(tBu2MeSi)2MeSi](tBu2MeSi)Si&dbd;SiMe(SiMetBu2) (3), which is the first methyl-substituted isolable disilene, and its structure was determined by X-ray crystallography. The regioselective addition of a methyl anion to the Si&dbd;Si bond in 3 took place to give the solvent-separated silyl anion species tetrakis(tetrahydrofuran)lithium(I) 1,1,5,5-tetra-tert-butyl-2,3-bis(di-tert-butylmethylsilyl)-1,2,4,4,5-pentamethylpentasilan-3-ide (4).

Published
2003

27. Fast and efficient critical state modelling of field-cooled bulk high-temperature superconductors using a backward computation method

Author

Zhang, K, Ainslie, Mark, Calvi, M, Hellmann, S, Kinjo, R, and Schmidt, T

Subjects
7. Clean energy
Abstract

A backward computation method has been developed to accelerate modelling of the critical state magnetization current in a staggered-array bulk high-temperature superconducting (HTS) undulator. The key concept is as follows: i) a large magnetization current is first generated on the surface of the HTS bulks after rapid field-cooling (FC) magnetization; ii) the magnetization current then relaxes inwards step-by-step obeying the critical state model; iii) after tens of backward iterations the magnetization current reaches a steady state. The simulation results show excellent agreement with the H-formulation method for both the electromagnetic and electromagnetic-mechanical coupled analyses, but with significantly faster computation speed. The simulation results using the backward computation method are further validated by the recent experimental results of a five period Gd-Ba-Cu-O (GdBCO) bulk undulator. Solving the finite element analysis (FEA) model with 1.8 million degrees of freedom (DOFs), the backward computation method takes less than 1.4 hours, an order of magnitude or higher faster than other state-of-the-art numerical methods. Finally, the models are used to investigate the influence of the mechanical stress on the distribution of the critical state magnetization current and the undulator field along the central axis., European Union's Horizon2020 Research & Innovation Program, Grant Agreement No. 777431 EPSRC Early Career Fellowship, EP/P020313/1

40. Development of material analysis facility in KU-FEL

Author

Yoshida, K., Sonobe, T., Zen, H., Bakr, M. A., Choi, Y. W., Mohamed Omer, Kinjo, R., Ishida, K., Kimura, N., Shimahashi, K., Komai, T., Shibata, M., Imon, H., Kii, T., Masuda, K., and Ohgaki, H.

50. Fully-staggered-array bulk Re-Ba-Cu-O short-period undulator: large-scale 3D electromagnetic modelling and design optimization using A-V and H-formulation methods

Author

Zhang, K, Ainslie, M, Calvi, M, Kinjo, R, and Schmidt, T

Subjects
critical state model, HTS modelling, finite element method, Physics::Accelerator Physics, H-formulation, backward computation, bulk superconductors, 7. Clean energy, undulator
Abstract

The development of a new hard x-ray beamline I-TOMCAT equipped with a 1-meter-long short-period bulk high-temperature superconductor undulator (BHTSU) has been scheduled for the upgrade of the Swiss Light Source (SLS 2.0) at the Paul Scherrer Institute (PSI). The very hard x-ray source generated by the BHTSU will increase the brilliance at the beamline by over one order of magnitude in comparison to other state-of-the-art undulator technologies and allow experiments to be carried out with photon energies in excess of 60 keV. One of the key challenges for designing a 1-meter-long (100 periods) BHTSU is the large-scale simulation of the magnetization currents inside 200 staggered-array bulk superconductors. A feasible approach to simplify the electromagnetic model is to retain five periods from both ends of the 1-meter-long BHTSU, reducing the number of degrees of freedom (DOFs) to the scale of millions. In this paper, the theory of the recently-proposed 2D A-V formulation-based backward computation method is extended to calculate the critical state magnetization currents in the ten-period staggered-array BHTSU in 3D. The simulation results of the magnetization currents and the associated undulator field along the electron beam axis are compared with the well-known 3D H-formulation and the highly efficient 3D H-{\phi} formulation method, all methods showing excellent agreement with each other as well as with experimental results. The mixed H-{\phi} formulation avoids computing the eddy currents in the air subdomain and is significantly faster than the full H-formulation method, but is slower in comparison to the A-V formulation-based backward computation. Finally, the fastest and the most efficient A-V formulation in ANSYS 2020R1 Academic is adopted to optimize the integrals of the undulator field along the electron beam axis by optimizing the sizes of the end bulks.

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