A5091048485- Particle Accelerators and Free-Electron Lasers
- Particle accelerators and beam dynamics
- Gyrotron and Vacuum Electronics Research
- Advanced X-ray Imaging Techniques
- Laser-Plasma Interactions and Diagnostics
- Laser Design and Applications
- Crystallography and Radiation Phenomena
- Superconducting Materials and Applications
- Particle Detector Development and Performance
- X-ray Spectroscopy and Fluorescence Analysis
- Photocathodes and Microchannel Plates
- Atomic and Subatomic Physics Research
- Nuclear Physics and Applications
- Magnetic confinement fusion research
- Atomic and Molecular Physics
- Terahertz technology and applications
- Radiation Detection and Scintillator Technologies
- Laser-Matter Interactions and Applications
- Advanced Radiotherapy Techniques
- Photonic and Optical Devices
- Geophysics and Sensor Technology
- Muon and positron interactions and applications
- Electron and X-Ray Spectroscopy Techniques
- Advanced Electron Microscopy Techniques and Applications
- Advanced Optical Sensing Technologies
High Energy Accelerator Research Organization
2015-2024
The Graduate University for Advanced Studies, SOKENDAI
2002-2016
Kharkiv Institute of Physics and Technology
2006
National Science Center
2006
Tokyo Metropolitan University
1999-2003
Waseda University
2002
Stanford University
2002
Sumitomo Heavy Industries (Japan)
1999
RIKEN
1983-1988
Tokyo Institute of Technology
1979-1982
An experiment to search for the production of neutral penetrating particles decaying into electron-positron pairs was performed with a 2.5-GeV electron beam. A total 0.027 C injected tungsten target. No such particle is found. Constraints on coupling constants ${\ensuremath{\alpha}}_{e}$ and ${\ensuremath{\alpha}}_{\ensuremath{\gamma}}$ are given.
$7.6\ifmmode\times\else\texttimes\fi{}{10}^{6}$ x-ray photons per 3.5 ps pulse are detected within a 1.8--2.3 \AA{} spectral window during proof-of-principle laser synchrotron source experiment. A 600 MW ${\mathrm{CO}}_{2}$ interacted in head-on collision with 60 MeV, 140 A, electron beam. Both beams were focused to $\ensuremath{\sigma}\phantom{\rule{0ex}{0ex}}=\phantom{\rule{0ex}{0ex}}32\ensuremath{\mu}\mathrm{m}$ spot. Our next plan is demonstrate ${10}^{10}$ using of...
We have demonstrated for the first time production of highly polarized short-pulse positrons with a finite energy spread in accordance new scheme that consists two-quantum processes, such as inverse Compton scattering and electron-positron pair creation. Using circularly laser beam 532 nm scattered off high-quality, 1.28 GeV electron beam, we obtained an intensity 2 x 10(4) e+ /bunch. The magnitude positron polarization has been determined to be 73 +/- 15(stat) 19(syst)% by means newly...
A free relativistic electron in an electromagnetic field is a pure case of light-matter interaction. In the laboratory environment, this interaction can be realized by colliding laser pulses with beams produced from particle accelerators. The process single photon absorption and reemission electron, so-called linear Thomson scattering, results radiation that Doppler shifted into x-ray gamma-ray regions. At elevated intensity, nonlinear effects should come play when transverse motion...
An experiment on the investigation of optical diffraction radiation (ODR) from a slit target as possible tool for noninvasive electron beam-size diagnostics has been performed at KEK accelerator test facility. The experimental setup installed section extraction line. We have first incoherent ODR observation target. measured angular distributions are in reasonable agreement with theoretical expectation. effect onto pattern observed. Moreover, sensitivity to beam size small 14 microm achieved.
A novel scheme for the focusing of high-energy leptons in future linear colliders was proposed 2001 [P. Raimondi and A. Seryi, Phys. Rev. Lett. 86, 3779 (2001)]. This has many advantageous properties over previously studied schemes, including being significantly shorter a given energy having better bandwidth. Experimental results from ATF2 accelerator at KEK are presented that validate operating principle such by demonstrating demagnification 1.3 GeV electron beam down to below 65 nm height...
Narrow-bandwidth photon beams in the x-ray and γ-ray energy ranges are expected to be applied various fields. An recovery linac (ERL)-based laser Compton scattering (LCS) source employing a enhancement cavity can produce high-flux narrow-bandwidth beam. We conducted first experiment of an ERL-based LCS combination with cavity. obtained photons 6.95±0.01 keV by colliding electron beam 20 MeV 1064 nm wavelength. The flux at interaction point was evaluated (2.6±0.1)×107 photons/s average...
For high luminosity in electron-positron linear colliders, it is essential to generate low vertical emittance beams. We report on the smallest achieved single-bunch-mode operation of Accelerator Test Facility, which satisfies requirement x-band collider. The emittances were measured with a laser-wire beam-profile monitor installed damping ring. bunch length and momentum spread beam also recorded under same conditions. rms at intensity 4 pm energy 1.3 GeV, corresponds normalized 1.0x1.0(-8)...
Thomson scattering of high-power laser and electron beams is a good test electrodynamics in the high-field region. We demonstrated production high-intensity X-rays head-on collision CO2 60-MeV at Brookhaven National Laboratory, Accelerator Test Facility. The energy an X-ray photon was limited 6.5 keV linear (lowest order) scattering, but nonlinear (higher process produces higher X-rays. measured angular distribution high-energy confirmed that it agrees with theoretical predictions.
X-ray generation based on laser-electron Compton scattering is one attractive method to achieve a compact laboratory-sized high-brightness x-ray source. We have designed, built, and tested such source; it combines 50 MeV multibunch electron linac with mode-locked 1064 nm laser stored amplified in Fabry–Pérot optical cavity. directly observed trains of pulsed x rays using microchannel plate detector; the resultant yield was found be 1.2×105 Hz good agreement prediction. believe that result...
We have developed a high-resolution cavity-beam position monitor (BPM) to be used at the focal point of ATF2, which is test beam line that now being built demonstrate stable orbit control $\ensuremath{\sim}\mathrm{\text{nanometer}}$ resolution. The design cavity structure was optimized for Accelerator Test Facility (ATF) in various ways. For example, has rectangular shape order isolate two dipole modes orthogonal directions, and relatively thin gap less sensitive trajectory inclination. A...
The Accelerator Test Facility 2 (ATF2) is a scaled demonstrator system for final focus beam lines of linear high energy colliders. This paper describes the resolution cavity position monitor (BPM) system, which part ATF2 diagnostics. Two types BPMs are used, C-band operating at 6.423 GHz, and S-band 2.888 GHz with an increased aperture. cavities, electronics, digital processing described. attenuators was determined to be approximately 250 nm 1 m system. Without attenuation best recorded 27 nm.
We present the response time measurements of a Cs2Te photocathode illuminated with two 100 fs duration, variable separation laser pulses at 266 nm wavelength. The was confirmed in dispersive region downstream 12-cell standing wave S-band acceleration structure using well-known RF zero-crossing technique. At same it also measured by changing mechanical path-length difference between micro-bunches. Both methods agree that is order 250 and thereby possible to generate control THz sequence...
Electron beams with the lowest, normalized transverse emittance recorded so far were produced and confirmed in single-bunch-mode operation of Accelerator Test Facility at KEK. We established a tuning method damping ring which achieves small vertical dispersion x-y orbit coupling. The was less than 1% horizontal emittance. At zero-intensity limit, 2.8 x 10(-8) rad m beam energy 1.3 GeV. high intensity, strong effects intrabeam scattering observed, had been expected view extremely particle...
An experiment to investigate the diffraction radiation from a single edge target has been performed at accelerator test facility of KEK with aim developing noninvasive beam diagnostics. The yield and angular distribution as function impact parameter was measured in visible light region. distributions were qualitatively consistent theoretical expectation. This work exhibits first observation incoherent
ATF2 is a final-focus test beam line which aims to focus the low emittance from ATF damping ring vertical size of about 37 nm and demonstrate nanometer level stability. Several advanced diagnostics feedback tools are used. In December 2008, construction installation were completed commissioning started, supported by an international team Asian, European, U.S. scientists. The present status first results described.
Based on the requirements from a conceptual design of polarized positron beam for future linear colliders, we constructed special collision system with short focal length 150 mm laser beams so as to produce $\ensuremath{\gamma}$ rays through inverse Compton scattering. In order achieve efficient laser-electron collisions, created optics very small ${e}^{\ensuremath{-}}$-beam sizes ${\ensuremath{\sigma}}_{{e}_{x0}}=7.6\text{ }\ensuremath{\mu}\mathrm{m}$ and...
We represent the first experimental observation of point spread function (PSF) optical transition radiation (OTR) performed at KEK-Accelerator Test Facility extraction line. have demonstrated that PSF vertical polarization component has a central minimum with two lobe distribution. However, distribution width varied significantly wavelength. assume we observed severe effect from spherical or chromatic aberrations which are not taken into account in any existing theoretical model. believe...
We report and discuss high-flux generation of circularly polarized γ-rays by means Compton scattering. The γ-ray beam results from the collision an external-cavity-enhanced infrared laser a low emittance relativistic electron beam. By operating non-planar bow-tie high-finesse optical Fabry-Perot cavity coupled to storage ring, we have recorded flux up (3.5 ± 0.3) × 108 photons per second with mean measured energy 24 MeV. has been sustained for several hours. In particular, were able measure...