A5040200387- Laser-Plasma Interactions and Diagnostics
- Particle accelerators and beam dynamics
- Particle Accelerators and Free-Electron Lasers
- Superconducting Materials and Applications
- Laser-Matter Interactions and Applications
- Laser-induced spectroscopy and plasma
- High-pressure geophysics and materials
- Atomic and Molecular Physics
- Advanced X-ray Imaging Techniques
- Crystallization and Solubility Studies
- Atomic and Subatomic Physics Research
- X-ray Diffraction in Crystallography
- Particle Detector Development and Performance
- Laser Design and Applications
- Physics of Superconductivity and Magnetism
- Electric Motor Design and Analysis
- Semiconductor Lasers and Optical Devices
- Nuclear Physics and Applications
- Gyrotron and Vacuum Electronics Research
- Graphene research and applications
- Spacecraft and Cryogenic Technologies
- HVDC Systems and Fault Protection
- Plasma Diagnostics and Applications
- Photonic and Optical Devices
- Ion-surface interactions and analysis
High Energy Accelerator Research Organization
2010-2024
Kyoto University
2003-2022
Panasonic (Japan)
2022
Japan Advanced Institute of Science and Technology
2020
University of Toyama
2012
Tohoku Gakuin University
2011
Kyoto University Institute for Chemical Research
2003-2009
Japan Atomic Energy Agency
2006-2009
Kyoto Bunkyo University
2009
Instituto de Investigaciones Químicas
2006-2009
With detailed experimental studies and hydrodynamics particle-in-cell simulations we investigate the role of prepulse in laser proton acceleration. The or pedestal (amplified spontaneous emission) can completely evaporate irradiated region a sufficiently thin foil; therefore, main part pulse interacts with an underdense plasma. multiparametric demonstrate that generates quasistatic magnetic field, which its turn produces long-lived charge separation electrostatic accelerating ions.
Duration-controlled amplified spontaneous emission with an intensity of ${10}^{13}\phantom{\rule{0.3em}{0ex}}\mathrm{W}∕{\mathrm{cm}}^{2}$ is used to convert a $7.5\text{\ensuremath{-}}\ensuremath{\mu}\mathrm{m}$-thick polyimide foil into near-critical plasma, in which the $p$-polarized, $45\text{\ensuremath{-}}\mathrm{fs}$, ${10}^{19}\text{\ensuremath{-}}\mathrm{W}∕{\mathrm{cm}}^{2}$ laser pulse generates $3.8\text{\ensuremath{-}}\mathrm{MeV}$ protons, emitted at some angle between target...
Fast protons are observed by a newly developed online time-of-flight spectrometer, which provides shot-to-shot proton-energy distributions immediately after the irradiation of laser pulse having an intensity ∼1018W∕cm2 onto 5-μm-thick copper foil. The maximum proton energy is found to increase when fs prepulse arriving 9ns before main increases from 1014 1015W∕cm2. Interferometric measurement indicates that preformed-plasma expansion at front surface smaller than 15μm, corresponds spatial...
A scheme of the real-time optimization proton production by an intense short-pulse laser interacting with a foil target was developed using time-of-flight measurement plastic scintillator. Owing to special treatments, detection protons scintillation counter has become possible under heavy backgrounds such as light itself, laser-generated hard X-ray, self-emission light, and electrons from laser-produced plasma. With protons, energy spectrum could be obtained shot shot, experimental...
The slow cycling main ring synchrotron (MR) is located the furthest downstream in J-PARC accelerator cascade. It became available for user operation 2009 and provides high-intensity 30 GeV proton beams various experiments on particle nuclear physics. MR has two beam extraction systems: a fast system delivery to neutrino line of Tokai-to-Kamioka (T2K) experiment hadron experimental hall. After nine-month shutdown during recovery from Great East Japan Earthquake, facility resumed December...
A study of proton emission from a 3-μm-thick Ta foil target irradiated by p-, s-, and circularly polarized laser pulses with respect to the plane has been carried out. Protons energies up 880keV were observed in normal direction under irradiation p-polarized pulse, which yielded highest efficiency for emission. In contrast, s- gave maximum 610 680keV, respectively. The difference energy between p- s-polarized cases was associated sheath fields estimated electron spectra.
In SuperKEKB, movable collimators reduce the beam background noise in Belle II particle detector and protect crucial machine components, such as final focusing superconducting quadrupole magnets (QCS), from abnormal losses. The challenges related to collimator, which were not properly considered at time of SuperKEKB design, have surfaced through experience with its operation. this paper, we report collimator operation strategy SuperKEKB. addition, a significant challenge collimation due...
The energy spectra and angular distributions of hot electrons as well protons emitted from a 3-μm-thick tantalum foil irradiated by 70-fs laser pulse with an intensity ∼1018W∕cm2 are measured. Three electron flows found, in the rear target normal, specular, surface directions. distribution is found to depend on polarization incident light. measured spectrum normal direction can explain generated proton beam.
A conductor temperature monitoring system using the current method was developed to estimate temperatures at joints of extra-high-voltage (EHV) underground power transmission XLPE cables in real time. The validity software and hardware confirmed by measurements on an extrusion molded joint (EMJ) a 275 kV 1*2500 mm/sup 2/ aluminum-sheathed cable. mean circumferential jacket surface over EMJ, where cross section larger than that cable portion, measured line thermosensor thermocouples or...
30 MVA superconducting synchronous condenser has been designed, fabricated, and tested successfully. The test suggested that the new approaches applied to machine were reasonable. field winding composed of six Nb-Ti two Nb <inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</inf> Sn coils, supported in torque-tube slots by wedges, was excited up rated operating current without training. amplitudes rotor vibration small special balance at cryogenic...
In order to widely spread out particle beams utilized in cancer therapy, laser-produced ions are developed as the injection beam for an ion synchrotron dedicated therapy. Such a laser source is expected contribute largely realization of compactness size and low cost therapy accelerator. The energy spectrum ions, however, has no peak, but their intensities decrease exponentially according increase energy. For purpose modifying such situation, we have proposed scheme rotate longitudinal phase...
A short-pulse (∼210 fs) high-power (∼1 TW) laser was focused on a tape target 3 and 5 µm in thickness to size of 11×15 µm2 with an intensity 3×1017 W/cm2. Protons produced by this energy spread 100% were found be improved create peaks the distribution ∼7% application RF electric field amplitude ±40 kV synchronous pulsed laser. This scheme combines conventional acceleration technique laser-produced protons for first time. It is possible operated up 10 Hz, have good reproducibility every shot...
An ion spectrometer, composed of a time-of-flight spectrometer (TOFS) and Thomson parabola (TPS), has been developed to measure energy spectra analyze species laser-driven ions. Two spectrometers can be operated simultaneously, thereby facilitate compare the independently measured data combine advantages each spectrometer. Real-time shot-to-shot characterizations have possible with TOFS, ions analyzed TPS. The two show very good agreement maximum proton even for single laser shot. composite...
It is important to control the magnet current for a high-intensity proton beam because magnetic field error displaces parameters (i.e., center of orbit, transverse tune, etc.) from ideal values and such displacements cause severe loss. This issue much more synchrotrons must be changed acceleration. For precise power supplies, we developed low-noise 24-bit A/D boards high-precision measurement. In addition, an algorithm DSP correct deviation. We successfully controlled at level ppm all...
The SuperKEKB was designed and constructed as the upgraded accelerator of KEKB. In this design, nano-beam scheme collision applied a luminosity 8 × 1035 cm−2s−1 targeted. beam final focus system key component in hardware elements. This consists 55 superconducting magnets. paper, designs magnets, cryostats cryogenic are shown, field measurement results reported. operation with started on 2018 March 19, magnet quench events up to 2020 December 16 described.
A laser-driven proton beam with a maximum energy of few MeV is stably obtained using an ultra-short and high-intensity Ti:sapphire laser. At the same time, keV X-ray also generated at almost place where protons are emitted. Here, we show successful demonstration simultaneous projection images test sample placed close to source resolution ∼10 µm, which determined from sizes. Although experimental configuration very simple, simultaneity better than hundreds ps. CR-39 track detector imaging...
We have developed a new method of measuring minimum quench energy (MQE) superconducting wire. There been conventional methods using heating wires, whose diameters are /spl sim/0.1 mm and glued by epoxy resin. When we induce pulse heat to duration the must be several hundreds micro seconds demonstrate actual disturbances (for instance wire motion) in magnet. In spite this fact, thermal diffusion time constants heaters larger than disturbance, because these electrical insulator bind....
A new detection device for evaluating the ion energy distributions of a laser-plasma source is demonstrated. The Imaging Plate (IP) with no protective layer as detector Thomson Parabola spectrometer used. (IPTPS) applicable analysis distribution laser-driven beam using an opto-electric digitizing technique.