A5075050114- Particle accelerators and beam dynamics
- Particle Accelerators and Free-Electron Lasers
- Magnetic confinement fusion research
- Laser-Plasma Interactions and Diagnostics
- Muon and positron interactions and applications
- Neutrino Physics Research
- Atomic and Molecular Physics
- Gyrotron and Vacuum Electronics Research
- Plasma Diagnostics and Applications
- Particle Detector Development and Performance
- Dark Matter and Cosmic Phenomena
- Particle physics theoretical and experimental studies
- Astrophysics and Cosmic Phenomena
- Radiation Detection and Scintillator Technologies
- Nuclear Physics and Applications
- Superconducting Materials and Applications
- Laser-induced spectroscopy and plasma
- Atomic and Subatomic Physics Research
- Advanced X-ray Imaging Techniques
- Ionosphere and magnetosphere dynamics
- X-ray Spectroscopy and Fluorescence Analysis
- Radiation Therapy and Dosimetry
- Solar and Space Plasma Dynamics
- Pulsed Power Technology Applications
- Scientific Measurement and Uncertainty Evaluation
Pohang University of Science and Technology
2024-2025
Ulsan National Institute of Science and Technology
2015-2024
Ulsan University Hospital
2024
Institute for Basic Science
2020-2023
Campbell Collaboration
2020-2022
A. Alikhanyan National Laboratory
2016-2021
GSI Helmholtz Centre for Heavy Ion Research
2018-2021
University of Maryland, College Park
2019
Manav Rachna International Institute of Research and Studies
2019
Google (United States)
2019
High energy particle accelerators have been crucial in providing a deeper understanding of fundamental particles and the forces that govern their interactions. In order to increase or reduce size accelerator, new acceleration schemes need be developed. Plasma wakefield acceleration, which electrons plasma are excited, leading strong electric fields, is one such promising novel technique. Pioneering experiments shown an intense laser pulse electron bunch traversing plasma, drives fields 10s...
This paper introduces a new approach to measure the muon magnetic moment anomaly |$a_{\mu} = (g-2)/2$| and electric dipole (EDM) |$d_{\mu}$| at J-PARC facility. The goal of our experiment is |$a_{\mu}$| using an independent method with factor 10 lower momentum, 20 smaller diameter storage-ring solenoid compared previous ongoing |$g-2$| experiments unprecedented quality storage field. Additional significant differences from present experimental include 1000 transverse emittance beam...
We give direct experimental evidence for the observation of full transverse self-modulation a long, relativistic proton bunch propagating through dense plasma. The exits plasma with periodic density modulation resulting from radial wakefield effects. show that is seeded by ionization front created using an intense laser pulse copropagating bunch. extends over length following seed point. By varying one order magnitude, we frequency scales expected dependence on density, i.e., it equal to...
The seeded self-modulation of a relativistic, charged particle bunch in plasma is shown to grow both along the and plasma, resulting transverse wakefield amplitudes that far exceed initial seed values.
We show in experiments that a long, underdense, relativistic proton bunch propagating plasma undergoes the oblique instability, which we observe as filamentation. determine threshold value for ratio between transverse size and skin depth instability to occur. At threshold, outcome of experiment alternates filamentation self-modulation (evidenced by longitudinal modulation into microbunches). Time-resolved images density distribution reveal grows an observable level late along bunch,...
AWAKE is a proton-driven plasma wakefield acceleration experiment. % We show that the experimental setup briefly described here ready for systematic study of seeded self-modulation 400\,GeV proton bunch in 10\,m-long rubidium with density adjustable from 1 to 10$\times10^{14}$\,cm$^{-3}$. short laser pulse used ionization vapor propagates all way along column, suggesting full vapor. occurs bunch, at time and follows affects bunch.
For more than 40 years, most astrophysical observations and laboratory studies of two key soft x-ray diagnostic 2p-3d transitions, 3C 3D, in Fe XVII ions found oscillator strength ratios f(3C)/f(3D) disagreeing with theory, but uncertainties had precluded definitive statements on this much studied conundrum. Here, we resonantly excite these lines using synchrotron radiation at PETRA III, reach, a millionfold lower photon intensities, 10 times higher spectral resolution, 3 smaller uncertainty...
Plasma wakefield acceleration is a promising technology to reduce the size of particle accelerators. The use high energy protons drive wakefields in plasma has been demonstrated during Run 1 AWAKE programme at CERN. Protons 400 GeV drove that accelerated electrons 2 under 10 m plasma. collaboration now embarking on with main aims demonstrate stable accelerating gradients 0.5–1 GV/m, preserve emittance electron bunches and develop sources scalable 100s metres beyond. By end 2, scheme should...
Experimental results show that hosing of a long particle bunch in plasma can be induced by wakefields driven short, misaligned preceding bunch. Hosing develops the plane misalignment, self-modulation perpendicular plane, at frequencies close to electron frequency, and are reproducible. Development depends on misalignment direction, its growth extent proton charge. Results have main characteristics theoretical model, relevant other plasma-based accelerators represent first characterization...
Измерены горизонтальный и вертикальный профили протонного пучка циклотрона C18/18 модернизированной диагностической станцией на базе мони- торов вибрирующей струны. Учитывая результаты первых экспериментов с использованием мониторов апертурой 14 мм накладными свинцовыми экранами, были разработаны мониторы расширенной (28 мм) магнитами, удаленными из зоны экспозиции пучка. Кроме того, датчики собраны толстой металлической базе, служащей коллиматором для Проблемы возникновения электромагнитных...
A long, narrow, relativistic charged particle bunch propagating in plasma is subject to the self-modulation (SM) instability. We show that SM of a proton can be seeded by wakefields driven preceding electron bunch. timing reproducibility and control are at level small fraction modulation period. With this seeding method, we independently amplitude seed with charge growth rate Seeding leads larger than instability case.
Abstract In the process of irradiation materials by fluxes heavy particles (protons, neutrons, alpha particles), damage to material structure is often observed. As a result accumulation such damages, there subsequent change in properties materials, particular, its embrittlement and hardening. Monitoring important for nuclear reactor vessels exposed high neutron fluxes. this work, observe effect on mechanical metals, we propose use vibrating wire resonators, which natural frequency...
We use a relativistic ionization front to provide various initial transverse wakefield amplitudes for the self-modulation of long proton bunch in plasma. show experimentally that, with sufficient amplitude [$\ensuremath{\ge}(4.1\ifmmode\pm\else\textpm\fi{}0.4)\text{ }\text{ }\mathrm{MV}/\mathrm{m}$], phase modulation along is reproducible from event event, 3%--7% (of $2\ensuremath{\pi}$) rms variations all bunch. The not lower amplitudes. observe transition between these two regimes. Phase...
Abstract We report on the first production of an antihydrogen beam by charge exchange 6.1 keV antiprotons with a cloud positronium in GBAR experiment at CERN. The 100 antiproton delivered AD/ELENA facility was further decelerated pulsed drift tube. A 9 MeV electron from linear accelerator produced low energy positron beam. positrons were accumulated set two Penning–Malmberg traps. target resulted conversion extracted steered onto this to produce antiatoms. observe excess over background...
We present a description of the GBAR positron (e+) trapping apparatus, which consists three stage Buffer Gas Trap (BGT) followed by High Field Penning (HFT), and discuss its performance. The overall goal experiment is to measure acceleration neutral antihydrogen (H¯) atom in terrestrial gravitational field neutralising positive ion (H¯+), has been cooled low temperature, observing subsequent H¯ annihilation following free fall. To produce one H¯+ ion, about 1010 positrons, efficiently...
In an uncoupled lattice, the Kapchinskij-Vladimirskij (KV) distribution function first analyzed in 1959 is only known exact solution of nonlinear Vlasov-Maxwell equations for high-intensity beams including self-fields a self-consistent manner. The KV generalized here to coupled transverse lattice using recently developed Courant-Snyder invariant dynamics. This projects rotating, pulsating elliptical beam configuration space, determined by matrix envelope equation.
The Courant-Snyder (CS) theory for one degree of freedom is generalized to the case coupled transverse dynamics in general linear focusing lattices with quadrupole, skew-quadrupole, dipole, and solenoidal components, as well torsion fiducial orbit variation beam energy. envelope function into an matrix, phase advance a 4D sympletic rotation. equation, transfer CS invariant original all have their counterparts, remarkably similar expressions, theory.
A major technological challenge in building a muon cooling channel is operating rf cavities multitesla external magnetic fields. We report the first proof-of-principle experiment of high pressure gas-filled cavity for use with intense ionizing beams and strong power consumption by beam-induced plasma investigated hydrogen deuterium gases pressures between 20 100 atm peak gradients 5 $50\text{ }\text{ }\mathrm{MV}/\mathrm{m}$. The low case agrees well an analytical model based on electron ion...
The performance of accelerators profits from phase-space tailoring by coupling degrees freedom. Previously applied techniques swap the emittances among three but set available is fixed. In contrast to these emittance exchange scenarios, transfer scenario presented here allows for arbitrarily changing as long product preserved. This Letter first experimental demonstration transverse along an ion beam line. amount chosen setting just one single magnetic field value. envelope functions (beta)...
We demonstrate a widely applicable technique to absolutely calibrate the energy scale of x-ray spectra with experimentally well-known and accurately calculable transitions highly charged ions, allowing us measure K-shell Rydberg spectrum molecular O$_2$ 8 meV uncertainty. reveal systematic $\sim$450 shift from previous literature values, settle an extraordinary discrepancy between astrophysical laboratory measurements neutral atomic oxygen, latter being calibrated against aforementioned...
Recent research on the Alcator C-Mod tokamak has focused a range of scientific issues with particular emphasis ITER needs and detailed comparisons between experimental measurements predictive models. Research ICRF (ion cyclotron frequencies) heating emphasized origins mitigation metallic impurities while work lower hybrid current drive experiments have linear nonlinear wave interactions that limit efficiency at high densities in regimes low single pass absorption. Experiments core turbulence...
The dynamics of charged particles in general linear focusing lattices with quadrupole, skew-quadrupole, dipole, and solenoidal components, as well torsion the fiducial orbit variation beam energy is parameterized using a generalized Courant-Snyder (CS) theory, which extends original CS theory for one degree freedom to higher dimensions. envelope function into an matrix, phase advance 4D symplectic rotation, or U(2) element. 1D equation, also known Ermakov-Milne-Pinney equation quantum...
A key requirement for the correct interpretation of high-resolution X-ray spectra is that transition energies are known with high accuracy and precision. We investigate K-shell features Ne, CO$_2$, SF$_6$ gases, by measuring their photo ion-yield at BESSY II synchrotron facility simultaneously 1s-np fluorescence emission He-like ions produced in Polar-X EBIT. Accurate ab initio calculations transitions these provide basis calibration. While CO$_2$ result agrees well previous measurements,...