Masahiro Katoh
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View article: Spectral phase interferometry for direct electric field reconstruction of chirped wavepackets generated from a tapered undulator
Spectral phase interferometry for direct electric field reconstruction of chirped wavepackets generated from a tapered undulator Open
Tapered undulators are designed to generate broadband, chirped radiation for advanced synchrotron light sources. However, the complete electric-field waveform of the radiation has never been directly measured. Here, we report the first dir…
View article: Attosecond Interferometry Experiments at the Tandem Undulator Beamline BL1U of UVSOR-III Synchrotron
Attosecond Interferometry Experiments at the Tandem Undulator Beamline BL1U of UVSOR-III Synchrotron Open
The waveform of electromagnetic radiation from an ultra-relativistic electron reflects the motion of the electron. Recently, we have demonstrated that each light wave packet comprising spontaneous radiation from a tandem undulator has a do…
View article: Emergence of Optical Activity and Surface Morphology Changes in Racemic Amino Acid Films Under Circularly Polarized Lyman‐α Light Irradiation
Emergence of Optical Activity and Surface Morphology Changes in Racemic Amino Acid Films Under Circularly Polarized Lyman‐α Light Irradiation Open
The homochirality of life remains one of the most enigmatic issues in the study of the origin of life. A proposed mechanism for symmetry breaking involves irradiation by circularly polarized light (CPL). To investigate the photoreaction of…
View article: Chirality in electromagnetic radiation from relativistic electrons
Chirality in electromagnetic radiation from relativistic electrons Open
Electrons in circular motion emit electromagnetic radiation and lose their energy and angular momentum, both of which are carried away by the radiation field. Electromagnetic radiation from such electrons is not only circularly polarized b…
View article: Bayesian optimization of the dynamic aperture in UVSOR-IV design study
Bayesian optimization of the dynamic aperture in UVSOR-IV design study Open
A lattice of a storage ring for the future plan of UVSOR synchrotron facility, UVSOR-IV, is designed at 1 GeV electron energy. The lattice of 12 compact double achromat cells conducts to an emittance of 4.2 nm at 1 GeV electron energy and …
View article: Light Source Developments at UVSOR BL1U
Light Source Developments at UVSOR BL1U Open
UVSOR, a low energy synchrotron light source, has been operational for about 40 years. It has been providing high brightness VUV radiation to users but also providing a research environment for light source developments. BL1U is a dedicate…
View article: Frequency-domain interferometry for the determination of time delay between two extreme-ultraviolet wave packets generated by a tandem undulator
Frequency-domain interferometry for the determination of time delay between two extreme-ultraviolet wave packets generated by a tandem undulator Open
Synchrotron radiation, emitted by relativistic electrons traveling in a magnetic field, has poor temporal coherence. However, recent research has proved that time-domain interferometry experiments, which were thought to be enabled by only …
View article: Prospects required for future light-source facilities: a case of UVSOR synchrotron facility
Prospects required for future light-source facilities: a case of UVSOR synchrotron facility Open
The synchrotron radiation facility is a large-scale public infrastructure that provides advanced light sources and is used for various academic research and application development. For 40 years, UVSOR Synchrotron Facility has been leading…
View article: Time domain double slit interference of electron produced by XUV synchrotron radiation
Time domain double slit interference of electron produced by XUV synchrotron radiation Open
We present a new realization of the time-domain double-slit experiment with photoelectrons, demonstrating that spontaneous radiation from a bunch of relativistic electrons can be used to control the quantum interference of single-particles…
View article: Spectral phase interferometry for direct electric-field reconstruction of synchrotron radiation
Spectral phase interferometry for direct electric-field reconstruction of synchrotron radiation Open
An undulator is a device widely used in synchrotron light sources to produce a certain quasi-monochromatic light; however, its waveform has never been recorded due to the lack of measurement techniques. Here we propose an approach to chara…
View article: Lattice design of the UVSOR-IV storage ring
Lattice design of the UVSOR-IV storage ring Open
We are designing a storage ring lattice for the future plan of UVSOR. As a candidate, we have designed a storage ring of 1 GeV electron energy, which is higher than the present value, 750 MeV. The magnetic lattice is based on a compact dou…
View article: Time structure of undulator radiation
Time structure of undulator radiation Open
A numerical method has been presented to compute the time structure of the radiation emitted from a relativistic electron moving inside an undulator, which plays important roles in the cutting-edge synchrotron radiation applications. The m…
View article: Coherent control of atoms in the extreme ultraviolet and attosecond regime by synchrotron radiation
Coherent control of atoms in the extreme ultraviolet and attosecond regime by synchrotron radiation Open
Control of interference between wave packets is one of the basic concepts in coherent control that enables quantum manipulation of populations and reaction pathways in matter. We have recently shown a new method to achieve coherent control…
View article: UVSOR Synchrotron Facility Update
UVSOR Synchrotron Facility Update Open
UVSOR is a Japanese low-energy synchrotron light source that has been operational since 1983. It has 750 MeV electron beam energy and a circumference of 53 m. The machine has undergone two major upgrades and is now called UVSOR-III, with a…
View article: Spectral phase interferometry for direct electric-field reconstruction of synchrotron radiation
Spectral phase interferometry for direct electric-field reconstruction of synchrotron radiation Open
Ultraviolet and extreme ultraviolet electric-fields produced by relativistic electrons in an undulator of a synchrotron light source are characterized by using spectral phase interferometry for direct electric-field reconstruction (SPIDER)…
View article: Fusion Visualization Technique to Improve a Three-Dimensional Isotope-Selective CT Image Based on Nuclear Resonance Fluorescence with a Gamma-CT Image
Fusion Visualization Technique to Improve a Three-Dimensional Isotope-Selective CT Image Based on Nuclear Resonance Fluorescence with a Gamma-CT Image Open
One of the most noteworthy aspects of computed tomography (CT) based on the nuclear resonance fluorescence (NRF) transmission method is the isotope selectivity that makes it possible to discern an isotope of interest from other isotopes wi…
View article: Three-Dimensional Nondestructive Isotope-Selective Tomographic Imaging of 208Pb Distribution via Nuclear Resonance Fluorescence
Three-Dimensional Nondestructive Isotope-Selective Tomographic Imaging of 208Pb Distribution via Nuclear Resonance Fluorescence Open
Combining the nuclear resonance fluorescence (NRF) transmission method with computed tomography (CT) can be a novel method for imaging the isotope distributions, which is indispensable in nuclear engineering. We performed an experiment to …
View article: Spatial structure and angular momentum of electro-magnetic wave radiated from a relativistic electron moving on a spiral orbit
Spatial structure and angular momentum of electro-magnetic wave radiated from a relativistic electron moving on a spiral orbit Open
We derive analytic expressions for the vector potential of electromagnetic wave radiated from a relativistic electron moving on a spiral orbit under an approximation that the velocity along the spiral orbit is much larger than that perpend…
View article: Present Status of HiSOR
Present Status of HiSOR Open
HiSOR is a compact synchrotron light source of 700MeV. The circumference is 22m. The ring has two straight sections for undulators, which provide high brilliance VUV radiation. Two 180 bending magnets have 2.7 T field strength, which provi…
View article: Lattice Design for a Future Plan of UVSOR Synchrotron
Lattice Design for a Future Plan of UVSOR Synchrotron Open
UVSOR is a 750 MeV synchrotron light source with a moderately small emittance of about 17nm. We surveyed the periodic solutions by drawing a tie diagram and mapped the emittance and the dynamic aperture on the tune diagram. The aim of this…
View article: Measurement of the phase structure of elliptically polarized undulator radiation
Measurement of the phase structure of elliptically polarized undulator radiation Open
This study theoretically and experimentally investigates the phase structure of radiation emitted from an elliptically polarized undulator. Analytic expressions for the emitted electromagnetic fields are fully derived and the radiation’s p…
View article: Effect of Cerium Addition to Bismuth–molybdenum Complex Oxide Catalyst for Partial Oxidation of Propylene to Acrolein
Effect of Cerium Addition to Bismuth–molybdenum Complex Oxide Catalyst for Partial Oxidation of Propylene to Acrolein Open
The effect of Ce addition to a Bi–Mo complex oxide catalyst supported on SiO2 was examined on the partial oxidation of propylene to acrolein. The catalyst consisted of an oxygen-supply phase in which the lattice oxygen in Mo-oxide was dope…
View article: Polarization control in a crossed undulator without a monochromator
Polarization control in a crossed undulator without a monochromator Open
In this study, it was demonstrated that the polarization control of light from a crossed undulator can be achieved using material response, without any prior monochromatization. Nonmonochromatized horizontally and vertically polarized radi…
View article: Selective Isotope CT Imaging Based on Nuclear Resonance Fluorescence Transmission Method
Selective Isotope CT Imaging Based on Nuclear Resonance Fluorescence Transmission Method Open
The isotope selectivity of computed tomography (CT) imaging based on nuclear resonance fluorescence (NRF) transmission method using a quasi-monochromatic laser Compton scattering (LCS) gamma-ray beam in the MeV region was demonstrated at t…
View article: Graphene as reusable substrate for bialkali photocathodes
Graphene as reusable substrate for bialkali photocathodes Open
Bialkali photocathodes, such as cesium potassium antimonide (CsK2Sb), can generate a high-brightness electron beam using a high-power green laser. These photocathode materials have potential applications in advanced accelerators and electr…
View article: Oxidative Dehydrogenation of Methane When Using TiO2- or WO3-Doped Sm2O3 in the Presence of Active Oxygen Excited with UV-LED
Oxidative Dehydrogenation of Methane When Using TiO2- or WO3-Doped Sm2O3 in the Presence of Active Oxygen Excited with UV-LED Open
There are active oxygen species that contribute to oxidative coupling or the partial oxidation during the oxidative dehydrogenation of methane when using solid oxide catalysts, and those species have not been definitively identified. In th…