A5081601845- Particle accelerators and beam dynamics
- Particle Accelerators and Free-Electron Lasers
- Magnetic confinement fusion research
- Laser-Plasma Interactions and Diagnostics
- Gyrotron and Vacuum Electronics Research
- Superconducting Materials and Applications
- Ion-surface interactions and analysis
- Plasma Diagnostics and Applications
- Laser-induced spectroscopy and plasma
- Atomic and Molecular Physics
- Bone Tissue Engineering Materials
- Pulsed Power Technology Applications
- High-pressure geophysics and materials
- Nuclear Physics and Applications
- X-ray Spectroscopy and Fluorescence Analysis
- Fusion and Plasma Physics Studies
- Electron and X-Ray Spectroscopy Techniques
- Laser-Matter Interactions and Applications
- Mass Spectrometry Techniques and Applications
- Particle Detector Development and Performance
- Advanced X-ray Imaging Techniques
- Additive Manufacturing and 3D Printing Technologies
- Fusion materials and technologies
- Solar and Space Plasma Dynamics
- Structural Analysis and Optimization
GSI Helmholtz Centre for Heavy Ion Research
2010-2021
Technical University of Darmstadt
2003-2021
First Technical University
2021
Goethe University Frankfurt
2012-2020
Research Association for Combustion Engines
1985-2015
Helmholtz Institute Jena
2011-2013
Max Planck Institute for Plasma Physics
1976-2012
Facility for Antiproton and Ion Research
2007-2008
Friedrich-Alexander-Universität Erlangen-Nürnberg
2005-2008
European Organization for Nuclear Research
2005
Based on self-consistent Vlasov-Poisson equations, we derive coherent frequencies and stability properties of anisotropic or ``nonequipartitioned'' beams with different focusing constants emittances in the two transverse directions. The thus obtained dispersion relations multipole oscillations quadrupolar, sextupolar, octupolar symmetries are solved numerically. We find that for sufficiently large energy anisotropy some eigenmodes become unstable space-charge-dominated regime. Applying our...
Using high energy accelerators for production by nuclear fission goes back to the 1950's with plans “breeder accelerators” as well early ideas on subcritical reactors, which are currently pursued in China and other countries. Also, fusion came in, when idea emerged mid 1970's use their highly time space compressed beams order generate extremely density temperatures required inertial production. Due higher repetition rates efficiencies of accelerators, this was seen a promising alternative...
Laser ion acceleration provides for compact, high-intensity sources in the multi-MeV range. Using a pulsed high-field solenoid, first time laser-accelerated proton bunches could be selected from continuous exponential spectrum and delivered to large distances, containing more than ${10}^{9}$ particles narrow energy interval around central of 9.4 MeV showing $\ensuremath{\le}30\text{ }\text{ }\mathrm{mrad}$ envelope divergence. The only few nanoseconds bunch duration were characterized 2.2 m...
Experimental results in laser acceleration of protons and ions theoretical predictions that the currently achieved energies might be raised by factors 5--10 next few years have stimulated research exploring this new technology for oncology as a compact alternative to conventional synchrotron based accelerator technology. The emphasis paper is on collection focusing produced particles using simulation data from specific model. We present scaling law ``chromatic emittance'' collector---here...
Using laser accelerated protons or ions for various applications---for example in particle therapy short-pulse radiographic diagnostics---requires an effective method of focusing and energy selection. We derive analytical scaling the performance a solenoid compared with doublet/triplet as function energy, which is confirmed by TRACEWIN simulations. Generally speaking, two approaches are equivalent capability, if parameters such that length approximately equals its diameter. The also shows...
The theory and simulation of coherent resonant coupling due to space charge in coasting or bunched anisotropic equilibrium beams is presented. Our work confirms that analytical results on oscillations instabilities KV (Kapchinskij-Vladimirskij) distributions are a valid tool interpret the findings from 2D 3D self-consistent particle-in-cell simulations for both waterbag distributions. With reference rings we discuss tune shifts up fourth order introduce coupled mode coefficient, which...
In linear devices the effective phase space volume occupied by a beam can grow rapidly if intensity is sufficiently close to charge limit and source of instability available, like periodic variation focusing force and/or considerable anisotropy between different planes. Results from analytic work computer simulation are compared shown support each other. Regimes defined in terms tunes tune depressions, where no emittance growth should occur; special emphasis given coupling case considerably...
In a particle accelerator with periodic structure beam space charge force may excite resonant emittance growth if the particle's transverse phase advance approaches 90\ifmmode^\circ\else\textdegree\fi{}. A recent simulation study PARMILA code [D. Jeon et al., Phys. Rev. ST Accel. Beams 12, 054204 (2009)] has shown feasibility of measuring stop band this fourth order resonance in GSI Universal Linear Accelerator UNILAC and proposed its experimental verification, which is reported here....
The combined effect of space charge and nonlinear resonance on beam loss emittance was measured in a benchmarking experiment over 1.2 s long flat bottom at 1.4 GeV kinetic energy the presence single controllable octupole. By lowering working point towards resonance, gradual transition from loss-free core blowup to regime dominated by continuous found. We compare observation with 3D simulations based new analytical model obtain good agreement regime. Our explanation is terms synchrotron...
Transverse emittance growth along the Alvarez drift tube linac (DTL) section is a major concern with respect to preservation of beam quality high current beams at GSI UNILAC. In order define measures reduce this growth, appropriate tools simulate dynamics are indispensable. This paper about benchmarking three simulation codes, i.e. DYNAMION, PARMILA, and PARTRAN against systematic measurements emittances for different transverse phase advances DTL. Special emphasis put on modeling initial...
Trapping of particles in nonlinear resonances the presence space charge and synchrotron motion may be a source beam halo generation loss high intensity synchrotrons, particular for extended storage times at injection plateau as planned SIS100 FAIR project. Although extensive simulation studies have theoretically demonstrated this mechanism, experimental evidence was so far limited to demonstration experiments CERN Proton Synchrotron (PS) 2002--2003 using an octupolar resonance. Here we...
The existence of a structural resonance stop band caused by space charge in high-current beams, where the frequency is associated with 90\ifmmode^\circ\else\textdegree\fi{} phase advance per focusing period, well known and alternatively referred to literature as envelope instability or fourth-order resonance. We show, however, that this actually coincidence much stronger competing mechanisms---depending on time scale initial matching. A similar complexity behavior---dependent distribution...
The new Schwerionen-Synchrotron (SIS)/Experimenteller Speicher-Ring (ESR) heavy ion accelerator facility [Nucl. Instrum. Methods A 278, 7, 19 (1989)], built for basic atomic and nuclear physics at Darmstadt (Federal Republic of Germany), also provides unique possibilities to study rf beam/target interaction inertial confinement fusion driven with beams. It is the first machine that offers this opportunity. Beam parameters experiments planned over next five years are discussed.
Parametric resonances of beam eigenmodes with a periodic focusing system under the effect space charge---also called structural instabilities---are collective counterparts to parametric single particles or mechanical systems. Their common feature is that an exponential instability driven by temporal modulation parameter. Thus, they are complementary more commonly considered charge particle resonances, where pseudo-multipole terms assumed exist already at finite level in initial distribution....
A detailed study of the influence space charge on crossing second-order resonances is presented and associated with space-charge limit high-intensity rings. Two-dimensional simulation studies are compared envelope models, which agree in finding an increased intensity due to coherent frequency shift. This result also found for realistic bunched beams multiturn injection painting. Characteristic features such as tune splitting, structure resonances, role instabilities discussed detail. The...