A5067387941- Particle accelerators and beam dynamics
- Plasma Diagnostics and Applications
- Magnetic confinement fusion research
- Particle Accelerators and Free-Electron Lasers
- Superconducting Materials and Applications
- Atomic and Molecular Physics
- Electrostatic Discharge in Electronics
- Gyrotron and Vacuum Electronics Research
- Nuclear Physics and Applications
- Particle Detector Development and Performance
- Mass Spectrometry Techniques and Applications
- Dust and Plasma Wave Phenomena
- Boron Compounds in Chemistry
- Global trade and economics
- Regional Economic and Spatial Analysis
- Ion-surface interactions and analysis
- Semiconductor materials and devices
- Laser-induced spectroscopy and plasma
- Earthquake and Disaster Impact Studies
- Integrated Circuits and Semiconductor Failure Analysis
- Urban and Freight Transport Logistics
- Regional Economics and Spatial Analysis
- Markov Chains and Monte Carlo Methods
- Bach Studies and Logistics Development
- Radiation Therapy and Dosimetry
High Energy Accelerator Research Organization
2009-2024
Japan Proton Accelerator Research Complex
2015-2024
Nippon Soken (Japan)
2023
Mitsubishi Electric (Japan)
2019
Keio University
2010-2017
Sumitomo Heavy Industries (Japan)
2017
Japan Atomic Energy Agency
2011
Yamaguchi University
2003
Hitachi (Japan)
2000
Kumamoto University
1991
CERN's Linac4 45 kV H− ion sources prototypes are installed at a dedicated source test stand and in the tunnel. The operation of pulsed hydrogen injection, RF sustained plasma, high voltages described. first experimental results two relying on 2 MHz RF-plasma heating presented. plasma is ignited via capacitive coupling, by inductive coupling. light emitted from collected viewports pointing to chamber wall middle solenoid axis. Preliminary measurements optical emission spectroscopy photometry...
CERN’s 160 MeV H− linear accelerator (Linac4) is a key constituent of the injector chain upgrade Large Hadron Collider that being installed and commissioned. A cesiated surface ion source prototype tested has delivered beam intensity 45 mA within an emittance 0.3 π ⋅ mm mrad. The optimum ratio co-extracted electron- to ion-current below 1 best production efficiency, defined as current 2 MHz RF-power transmitted plasma, reached 1.1 mA/kW. first tests new optics, electron-dump, front end...
Two volume sources equipped with DESY and CERN plasma generators a low voltage electron dump were operated at 45 kV in the Linac4 tunnel on dedicated test stand. These delivered approximately 20 mA ensured commissioning of Radio Frequency Quadrupole accelerator first section Drift Tube Linac. CERN's prototype cesiated surface source this was continuously from November 2013 to April 2014 ion stand is being commissioned tunnel. Before cesiation, conditioned mode provided up 30 H− beam. Short...
The present status of kinetic modeling particle dynamics in hydrogen negative ion (H−) source plasmas and their comparisons with experiments are reviewed discussed some new results. main focus is placed on the following topics, which important for research development H− sources intense high-quality beams: (i) effects non-equilibrium features electron energy distribution function volume surface production, (ii) origin spatial non-uniformity giant multi-cusp arc-discharge sources, (iii)...
Spatial non-uniformity of the dissociative hydrogen atom (H0) production has been investigated in a large negative ion source (JAEA 10 A source) with electron energy distribution function (EEDF) obtained by Monte-Carlo simulation code for transport 3D3V (three dimensional real and velocity) space. It shown that H0 rate becomes larger upper region (one side longitudinal direction) chamber. This spatial profile is mainly explained non-equilibrium features EEDF region, i.e., consists thermal...
Time structure of Balmer Hα line intensity in Linac4 RF plasma has been analyzed by the combined simulation model atomic transport and Collisional-Radiative models. As a preliminary result, time variation ignition phase is calculated compared with experimental results photometry. For comparison, spatial distribution local photon emission rate at each from numerical model. The contribution rates to observed via optical viewing port also investigated application mock-up known light source. It...
For the upgrade of Japan Proton Accelerator Research Complex linac beam current, a cesiated RF-driven negative hydrogen ion source was installed during 2014 summer shutdown period, with subsequent operations commencing on September 29, 2014. The has been successfully operating current and duty factor 33 mA 1.25% (500 μs 25 Hz), respectively. result recent operation demonstrated that is capable continuous for approximately 1100 h. spark rate at extractor observed to be frequency less than...
In the 2017/2018 campaign, J-PARC cesiated rf-driven negative hydrogen (H−) ion source producing H− beam with current of 47 mA accomplished three long-term operations more than 2,000 hours without any serious issues. On final day this produced an 72 so that linac commissioning group could demonstrate 60 at exit. We are also conducting endurance test a J-PARC-made antenna bench. The achieved operation time approximately 1,400 hours.
In order to evaluate Electron Energy Distribution Function (EEDF) more correctly for radio frequency inductively coupled plasma (RF-ICP) in hydrogen negative ion sources, the Electromagnetic Particle-In-Cell (EM-PIC) simulation code has been improved by taking into account electron-electron Coulomb collision. Binary collision model is employed process and we have successfully modeled it. The preliminary calculation including done it shown that doesn't significant effects under condition:...
A filament driven multi-cusp negative ion source has been developed for proton cyclotrons in medical applications. In Cs-free operation, continuous H(-) beam of 10 mA and D(-) 3.3 were obtained stably at an arc-discharge power 3 kW 2.4 kW, respectively. Cs-seeded current reached 22 a lower arc 2.6 with less co-extracted electron current. The optimum gas flow rate, which gives the highest current, was 15 sccm while it decreased to 4 operation. relationship between production design/operating...
A cesiated RF-driven negative hydrogen ion source was started to operate in September, 2014 response the need for upgrading J-PARC's linac beam current. The mainly comprises a stainless-steel plasma chamber, extractor, and large vacuum chamber with two turbo molecular pumps of 1500 L/s differential pumping. has been successfully providing required current accelerator without any significant issues other than single-incident antenna failure occurred October, 2014. Continuous operation...
Progress in the kinetic modeling of particle dynamics H(-) negative ion source plasmas and their comparisons with experiments are reviewed, discussed some new results. Main focus is placed on following two topics, which important for research development large sources high power beams: (i) Effects non-equilibrium features EEDF (electron energy distribution function) production, (ii) extraction physics ions beam optics.
Oscillation of emittance and Twiss parameters in the negative ion (H−) beam from J-PARC 2MHz RF source is measured by application a double-slit monitor located at RFQ entrance. The equipped with newly-developed 60 MS/s data acquisition system, so that current oscillations few MHz can be observed enough time resolution. From measurement, it shown phase space consists of: (1) Direct Current component core; (2) 2 oscillating which takes place diverging halo; (3) doubled frequency (4 MHz)...
In the Japan Proton Accelerator Research Complex (J-PARC), peak H− current of several tens mA is produced from a cesiated hydrogen plasma generated by solid-state radio-frequency (RF) amplifier with frequency 2 MHz. case high-intensity H- beam extracted ion source, density in source chamber so high that sheath around extraction area follows RF oscillation. Because defined much higher than driving frequency. The potential fluctuation combined electric field and causes motion charged particles...
Balmer alpha line intensity in J-PARC Radio Frequency (RF) negative hydrogen ion source has been measured by photometry measurement. The shows several interesting time characteristics different phases; (1) 2 MHz (RF frequency) oscillation just after plasma ignition and (2) 4 (doubled RF 2MHz coupled the steady-state. From comparison between numerical analysis, it explained that electron acceleration inductively electromagnetic field takes place with frequency which results oscillation....
To control the H0 atom production profile in H− ion sources is one of important issues for efficient and uniform surface production. The purpose this study to construct a collisional radiative (CR) model calculate effective rate atoms from H2 molecules geometry radio-frequency (RF) source Linac4 accelerator. In order validate CR by comparison with experimental results optical emission spectroscopy, it also necessary Balmer photon source. As basic test model, time evolutions Hα are calculated...
Spatial profiles of the atomic (H0) density and resultant Hα line intensity are investigated in a large negative ion source (the Japan Atomic Energy Agency (JAEA) 10 A source). The H0 analysis has been done present study with effects production, transport, ionization processes by taking into account non-Maxwellian component electron energy distribution function (EEDF). profile shows non-uniform spatial due to local enhancement production rate even flattening transport processes. observed...
A filament driven multi-cusp negative hydrogen ion source has been developed for proton cyclotrons. In order to increase the H− beam current, dependences of current on various design/operating parameters studied experimentally and numerically. this paper, effects arc-discharge voltage production via volume process are investigated by three-dimensional kinetic modeling electrons in plasma zero-dimensional rate equations. This numerical analysis reproduces experimental results dependence...
Ignition and steady state phases of Radio Frequency (RF) plasma in J-PARC ion source has been investigated by numerical modeling. The model takes into account the transport particles (electrons, protons, hydrogen molecular ions cesium ions) electromagnetic (EM) field with collision processes. Inductively coupled capacitive EM fields are simultaneously solved transport. Applying KEK parallel computation system A (64 cores, 56 nodes 256 GB memory per node), behavior high density up to 1019 –...
The AC component of a beam current extracted from negative hydrogen (H-) ion source was detected through 0.1 mm wide, 66.5 long entrance slit to observe the spatial distribution. An internal antenna type multicusp driven by 2 MHz radio frequency (RF) power delivered beams an electrostatic accelerator coupled pair magnetic lenses. local intensity measured Faraday cup after exhibited oscillation showing two main components: RF supply and times driving RF. spectrum signal showed sharp peaks at...
A filament driven multi-cusp negative ion source has been developed for proton cyclotron applications. In this study, numerical analysis of the H− volume production in conducted by KEIO-MARC code and zero dimensional rate equations. The calculate Electron Energy Distribution Function (EEDF) arc discharge sources from following main input parameters: 1) 3D geometry chamber filaments, 2) magnetic configuration, 3) voltage, 4) current 5) gas pressure. Using EEDF, we can also estimate resultant...
Recently, a filament driven multi-cusp negative ion source has been developed for proton cyclotrons in medical applications. In this study, numerical modeling of the arc-discharge plasma done with kinetic electrons plasmas by code and zero dimensional rate equations hydrogen molecules ions. paper, main focus is placed on effects power electron energy distribution function resultant H− production. The modelling results reasonably explains dependence extraction current experiments.