A5077212066- Particle Accelerators and Free-Electron Lasers
- Gyrotron and Vacuum Electronics Research
- Particle accelerators and beam dynamics
- Nuclear Physics and Applications
- Radiation Detection and Scintillator Technologies
- Advanced X-ray Imaging Techniques
- Laser-Matter Interactions and Applications
- Laser Design and Applications
- Terahertz technology and applications
- Laser-Plasma Interactions and Diagnostics
- Medical Imaging Techniques and Applications
- Photonic and Optical Devices
- Advanced Fiber Laser Technologies
- Atomic and Subatomic Physics Research
- Nuclear physics research studies
- Advanced Electron Microscopy Techniques and Applications
- Laser Material Processing Techniques
- Spectroscopy and Laser Applications
- Cold Fusion and Nuclear Reactions
- Advanced X-ray and CT Imaging
- Fusion and Plasma Physics Studies
- Physics of Superconductivity and Magnetism
- Advanced MRI Techniques and Applications
- Radiation Therapy and Dosimetry
- Photocathodes and Microchannel Plates
Kyoto University
2016-2025
Advanced Energy (United States)
2022-2025
Kyoto Bunkyo University
2013-2020
National Institutes of Natural Sciences
2010-2019
National Institutes for Quantum Science and Technology
2019
National Institute of Advanced Industrial Science and Technology
2019
Tohoku University
2018
Nagoya University
2018
Yamagata University
2018
Shizuoka University
2018
The detailed structure of superradiant pulses generated from a free-electron laser (FEL) oscillator was experimentally revealed for the first time. Owing to phase retrieval with combination linear and nonlinear autocorrelation measurements, we successfully reconstructed temporal waveform an FEL pulse including its variation. clearly exhibits features pulse, main followed by train sub-pulses π-phase jumps, reflecting physics light-matter resonant interaction. From numerical simulations, found...
A synthetic diagnostic of x-ray bremsstrahlung radiation and a Monte Carlo transport simulation were carried out to obtain the electron energy distribution in stochastic acceleration experiments Heliotron J, mid-sized heliotron-type magnetic confinement device. Three sets LaBr3(Ce) scintillator photomultiplier tubes installed J three directions relative field line, co, counter, perpendicular, determine velocity high-energy electrons. These systems are positioned about 5 m away from vacuum...
A mid-infrared Free Electron Laser (FEL) named as Kyoto University FEL (KU-FEL) has been developed for energy-related research at Institute of Advanced Energy, University. The wavelength range KU-FEL is 3.6 - 23 μm and opened various user experiments. compact THz-FEL, which consists a photocathode RF gun, bunch compressor, an undulator, now under construction. Present status perspective the facility reported in this paper.
A 750 MeV low energy synchrotron light source, UVSOR, has been operational since 1983. To meet the strong demands for brighter light, an upgrade project was performed in 2003, which emittance reduced from 160 nm-rad to 27 and four 1.4-m long short straight sections were created. Thereafter, source renamed UVSOR-II. During ten years after this major upgrade, we have continued upgrading source. The top-up injection scheme introduced a new 4-m section created by moving point. In 2012, bending...
A Neutron/Gamma-ray combined inspection system for hidden special nuclear materials (SNMs) in cargo containers has been developed under a program of Japan Science and Technology Agency Japan. This consists an active neutron-detection fast screening laser Compton backscattering gamma-ray source coupling with resonance fluorescence (NRF) method precise inspection. The inertial electrostatic confinement fusion device adopted as neutron two methods, delayed noise analysis high-energy method,...
Development of a laser Compton scattering (LCS) gamma-ray source in the UVSOR-III storage ring has been proposed to perform basic research on non-destructive three dimensional isotope imaging. As first step development, numerical simulation was performed evaluate performance source. The expected total flux is about 1×107 photons/s when 1.94-μm CW fiber with maximum power 5 W collides 300-mA electron beam circulating ring. energy and available were measured experiment determined as 5403 ± 16...
The extraction efficiency is one of the key parameters an oscillator-type free electron laser (FEL). An higher than 5% was observed with midinfrared (MIR) FEL at Kyoto University using a dynamic cavity desynchronization method. highest realized in MIR-FEL oscillators driven by normal conducting linacs. A numerical simulation performed, and evolution energy distribution macropulse compared experimental result. details were investigated to reveal physics this high-efficiency lasing.
Inverse Compton scattering of polarized laser photons by energetic electrons is an excellent method to generate gamma rays. A 100% can rays, but polarization varies depending on the angle In this study, we experimentally measure spatial distribution circularly rays using a magnetized iron that circular MeV Measurements asymmetry gamma-ray transmission relative at each clearly show are near central axis, and they change from linear as increases. simple way obtain highly use collimator...
Laser amplification using a 12 µm mid-infrared free-electron laser (MIR-FEL) was observed at the Institute of Advanced Energy (IAE), Kyoto University. A 25 MeV electron beam 17 peak current used for lasing experiment. loading compensation method with an RF amplitude control in thermionic gun to extend macropulse duration against backbombardment effect gun. As result, 4 µs generated. output intensity 50 times as high spontaneous emission observed. FEL gain estimated be 16% from exponential...
Relativistic electron bunches circulating in accelerators are subjected to a dynamical instability leading microstructures at millimeter centimeter scale. Although this is well-known fact, direct experimental observations of the structures, or field that they emit, remained up now an open problem. Here, we report direct, shot-by-shot, time-resolved recording shapes (including envelope and carrier) pulses coherent synchrotron radiation emitted, "signature" bunch microstructure. The...
The thermally assisted photoemission (TAPE) effect was investigated for the hexaboride thermionic cathodes (${\mathrm{LaB}}_{6}$ and ${\mathrm{CeB}}_{6}$). It found that quantum efficiency of these can be increased by raising cathode temperature along with emission. In addition both materials emit a measurable current being irradiated laser having photon energy below work function at sufficiently high temperatures. Our measurements indicate this process is linear. These results show...
The first ever practical-level field generation for an undulator consisting of bulk high-temperature superconductors is reported and described. A high-field short-period enables bright hard X-ray to be obtained in moderate-energy synchrotrons provide a polarized MeV gamma-ray source producing positron beam via pair production future linear colliders. To generate sinusoidal magnetic fields using superconductors, novel structure has been developed which the line up staggered configuration...
The back bombardment (BB) effect limits wide usage of thermionic rf guns. BB induces not only ramping-up a cathode's temperature and beam current, but also degradation cavity voltage energy during macropulse. This paper presents comparison the for case dispenser tungsten-base (DC) lanthanum hexaboride (${\mathrm{LaB}}_{6}$) gun cathodes. For each, particle simulation codes are used to simulate electron dynamics in cathode. A semiempirical equation is investigate stopping range deposited heat...
We report the pulse duration and wavelength stability measurements of a midinfrared free-electron laser (FEL) where fluctuation may not be negligible. The technique we employ is fringe-resolved autocorrelation (FRAC) method that has good sensitivity on only chirp but also stability. By simple manipulation experimental FRAC signals, can obtain even if amounts are known in advance, which further used to estimate Through this procedure find Kyoto University FEL at 12 μm about 0.58 ps without...
The magnetic field of a staggered-array undulator using bulk high-temperature superconductor is calculated by analytical and numerical methods. Analytical formulas for the solenoid required to generate are derived from simple two-dimensional model. calculation shows degree dependence these fields on parameters, generation high proportional critical current density superconductor, good tunability over wide range values. performed in three-dimensional geometry two methods: center energy...
Computed Tomography (CT) using X-ray attenuation by atomic effects is now widely used for medical diagnosis and industrial non-destructive inspection. In this study, we performed a tomographic imaging of isotope (208Pb) distribution the Nuclear Resonance Fluorescence (NRF), i.e. specific resonant absorption scattering gamma rays, Laser Compton Scattering (LCS) rays. The NRF-CT image which includes both nuclear was obtained. By accounting measured conventional method at same time, clear 208Pb...
Abstract UVSOR, a low energy synchrotron light source, has been operational for about 40 years. It providing high brightness VUV radiation to users but also research environment source developments. BL1U is dedicated beamline developments and applications of novel technologies. The equipped with two variable-polarization undulators phase-shifter magnet femto-second laser system which synchronized the RF acceleration. We have studying oscillator-type free electron laser, coherent harmonic...
Abstract FEL oscillators can produce few-cycle optical pulses with a high-extraction efficiency when the are operated in superradiant regime. Such unique light sources to explore intense field science, especially mid-infrared and longwave infrared where ultrashort for high-intensity applications difficult from conventional lasers. Since laser-matter interaction regime is described terms of oscillating electric rather than instantaneous intensity, carrier-envelope phase (CEP) must be...
Abstract The maximum energy of photons from high-harmonic generation (HHG) increases with the wavelength driving laser. A free electron laser (FEL) is a continuously tunable light source in mid-IR range and it useful for investigating extension accessible photon HHG. Recently, undulator magnets IR FEL at Laboratory Electron Beam Research Application (LEBRA), Nihon University, have been replaced, then output power has increased. Here, we evaluate pulse duration focal beam size show that LEBRA...
Abstract Intense infrared (IR) rays can heat matters and evaporate waters thermally. One of the possible applications will be hair dryer, although irradiation effects IR on have not been fully explored. In this study, we first examined interaction at various wavelengths from 3.0 µm (near IR) to 90 (far with surface structure human by using free electron lasers (FELs). IR-FEL is an accelerator-based pico-second pulse laser, feature wavelength-tunability high-photon density. When one thread...