K. Watanabe
A5069402875- Particle accelerators and beam dynamics
- Magnetic confinement fusion research
- High-Energy Particle Collisions Research
- Particle physics theoretical and experimental studies
- Quantum Chromodynamics and Particle Interactions
- Plasma Diagnostics and Applications
- Superconducting Materials and Applications
- Particle Accelerators and Free-Electron Lasers
- Fusion materials and technologies
- Gyrotron and Vacuum Electronics Research
- Electrostatic Discharge in Electronics
- Nuclear reactor physics and engineering
- Ion-surface interactions and analysis
- Particle Detector Development and Performance
- Pulsed Power Technology Applications
- Laser-Plasma Interactions and Diagnostics
- Mass Spectrometry Techniques and Applications
- Radiation Detection and Scintillator Technologies
- Nuclear Physics and Applications
- Silicon Carbide Semiconductor Technologies
- Dark Matter and Cosmic Phenomena
- Photonic Crystals and Applications
- Metal and Thin Film Mechanics
- Muon and positron interactions and applications
- Nuclear Materials and Properties
Laboratoire de Physique Subatomique et des Technologies Associées
2021-2025
IMT Atlantique
2021-2025
Nantes Université
2021-2024
Institut National de Physique Nucléaire et de Physique des Particules
2021-2024
Centre National de la Recherche Scientifique
2021-2024
Rikkyo University
2012-2024
RIKEN Nishina Center
2014-2024
Tohoku University
2000-2024
Seikei University
2022-2023
University of Ljubljana
2023
The ITER Neutral Beam Test Facility (NBTF), called PRIMA (Padova Research on Megavolt Accelerator), is hosted in Padova, Italy and includes two experiments: MITICA, the full-scale prototype of heating neutral beam injector, SPIDER, full-size radio frequency negative-ions source. NBTF realization exploitation SPIDER MITICA have been recognized as necessary to make future operation injectors efficient reliable, fundamental achievement thermonuclear-relevant plasma parameters ITER. This paper...
The ITER project requires additional heating by two neutral beam injectors, each accelerating to 1 MV a 40 A of negative deuterium ions, deliver the plasma power about 17 MW for one hour. As these requirements have never been experimentally met, it was recognized as necessary setup test facility, PRIMA (Padova Research on Megavolt Accelerator), in Italy, including full-size ion source, SPIDER, and prototype whole injector, MITICA, aiming develop injectors be installed ITER. This realization...
We revisit the issue of large negative next-to-leading order (NLO) cross section for single inclusive hadron production in $pA$ collisions saturation formalism. By implementing exact kinematical constraint modified dipole splitting functions, two additional positive NLO correction terms are obtained. In asymptotic $k_\perp$ limit, we analytically show that these become as contributions found our previous calculation. Furthermore, numerical results demonstrate applicable regime formalism can...
Heating neutral beam (HNB) injectors, necessary to achieve burning conditions and control plasma instabilities in ITER, are characterized by such demanding parameters that a test facility (NBTF) dedicated their development optimization is being realized Padua (Italy) with direct contributions from the Italian government (through Consorzio RFX as host entity) ITER international organization (with kind domestic agencies of Europe, Japan India) technical scientific support various European...
Heavy flavor measurements in high multiplicity proton-proton and proton-nucleus collisions at collider energies enable unique insights into their production hadronization mechanism because experimental theoretical uncertainties cancel ratios of cross sections relative to minimum bias events. We explore such event engineering using the color glass condensate (CGC) effective field theory compute short-distance charmonium sections. The CGC is combined with heavy-quark fragmentation functions...
Hydrogen negative ion beams of 507 keV, 1 A and 486 2.8 have been successfully produced in the JT-60U source with a three-stage accelerator by overcoming poor voltage holding large-size grids ∼2 m 2 . This is first result H − beam acceleration up to 500 keV at high current over A. In order improve capability, breakdown voltages small-size electrodes uniform locally strong electric fields were examined changing gap length. It was found that below half field which used design accelerator....
Significant progress in the extension of pulse durations powerful negative ion beams has been made to realize neutral beam injectors for JT-60SA and ITER. In order overcome common issues long-pulse production/acceleration ITER, new technologies have developed source MeV accelerator Japan Atomic Energy Agency.
The Future Circular Collider (FCC) Study is aimed at assessing the physics potential and technical feasibility of a new collider with centre-of-mass energies, in hadron-hadron collision mode, seven times larger than nominal LHC energies. Operating such machine heavy ions an option that being considered accelerator design studies. It would provide, for example, Pb-Pb p-Pb collisions sqrt{s_NN} = 39 63 TeV, respectively, per nucleon-nucleon collision, integrated luminosities above 30 nb^-1...
A bstract For studying small- x gluon saturation in forward dijet production high-energy dilute-dense collisions, the improved TMD (ITMD) factorization formula was recently proposed. In Color Glass Condensate (CGC) framework, it represents leading term of an expansion inverse powers hard scale. It contains leading-twist relevant for small gluon’s transverse momentum k t , but also incorporates all-order resummation kinematical twists, resulting a proper matching to at large . this paper, we...
Developments of the large negative ion source have been progressed in high-energy, high-power, and long-pulse neutral beam injector for JT-60 Super Advanced. Countermeasures studied tested critical issues grid heat load voltage holding capability. As acceleration grids, direct interception D- ions was reduced by adjusting beamlet steering. a result, below an allowable level injections. capability, local electric field mitigated tuning gap lengths between large-area grids accelerator....
We argue that the large suppression of $\psi(2S)$ inclusive cross-section relative to $J/\psi$ in proton-nucleus (p+A) collisions can be attributed factorization breaking effects formation quarkonium. These arise from soft color exchanges between charm-anticharm pairs undergoing hadronization and comoving partons are long-lived on time scales quarkonium formation. compute short distance pair production heavy quarks Color Glass Condensate (CGC) effective field theory employ an improved...
Views Icon Article contents Figures & tables Video Audio Supplementary Data Peer Review Share Twitter Facebook Reddit LinkedIn Tools Reprints and Permissions Cite Search Site Citation Y. Okumura, M. Hanada, T. Inoue, H. Kojima, Matsuda, Ohara, Seki, K. Watanabe; Cesium mixing in the multi‐ampere volume H− ion source. AIP Conf. Proc. 5 August 1990; 210 (1): 169–183. https://doi.org/10.1063/1.39587 Download citation file: Ris (Zotero) Reference Manager EasyBib Bookends Mendeley Papers EndNote...
The current drive and heating properties of negative ion based NBI have been studied comprehensively in JT-60U. It has confirmed from shine-through measurements the injected beam (350 keV) that multistep ionization processes are essential high energy particles. profile density driven by a NB (N-NB) determined experimentally. This is good agreement with theoretical prediction, N-NB reached 0.6 MA EB = 360 keV PINJ 3.7 MW. efficiency ηCD increased increasing electron temperature improved...
The 500-keV negative-ion based neutral beam injector for JT-60U started operation in 1996. power has been increased gradually through optimizing parameters of the ion sources and conquering many troubles source supplies caused by a high voltage break-down accelerator. However, some issues remain to be solved concerning increasing further energy. most serious issue them is non-uniformity plasma arc chamber. Various countermeasures have implemented improve non-uniformity. Some those found...
A large volume negative ion source, which has a newly devised magnetic filter called PG filter, was designed and tested. The produces uniform field over extraction area of 14×36 cm2 by flowing high current through the plasma grid itself. By optimizing strength, we succeeded to produce 3.4-A 75-keV hydrogen beams for 50 ms from 253 apertures 11.3 mm diam with an average H− density 13 mA/cm2.
Major issues of neutral beam (NB) injector power supplies are high-speed switching, regulation and transmission dc ultra-high voltage (UHV) suppression surge energy input to the source at high breakdown. A gate turn-off thyristor inverter type supply where control is performed on low ac side was designed for ITER NB. Based remarkable progress a IEGT (injection enhanced transistor), design has been modified increase efficiency compactness using such new elements. The loss in reduced 0.5 MW...