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| THPVA003 | Status of the Beam Dynamics Design of the New Post-Stripper DTL for GSI-FAIR | 4414 |
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| The GSI UNILAC has served as injector for all ion species since 40 years. Its 108 MHz Alvarez DTL providing acceleration from 1.4 MeV/u to 11.4 MeV/u has suffered from material fatigue and has to be replaced by a new section. The design of the new post-stripper DTL is now under development in GSI. Five Alvarez tanks with four intertank sections provide 100% transmission and low emittance growth. The intertank sections allow for a matched solution and provide place for diagnostics. Simulations along the complete Alvarez DTL were done for 238U28+ using the TraceWin code. The transversal zero current phase advance is 65' for all tanks. Results of beam dynamics simulations for six different scenarios as well as an error study for the FAIR nominal case are presented. | ||
| DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-THPVA003 | |
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| THPVA005 | Investigation of Electron Beam Assisted Density Boosting in Plasma Traps Using the Example of a Gabor Plasma Lens | 4421 |
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Gabor lenses are plasma traps that can be used for focusing an ion beam linearly without aberrations* by the electric field of a confined electron cloud. They combine strong electrostatic focusing with the possibility of space charge compensation and provide an attractive alternative to conventional ion beam optics in a LEBT section. The focusing performance strongly depends on the density and distribution of the enclosed electron plasma*. As the Gabor lens is usually operated close to the ion source, residual gas ionization is supposed to be the central electron generation mechanism. An electron source is introduced in order to investigate the possibility of boosting the electron density in plasma traps using the example of a Gabor lens. This way, a Gabor lens could be operated under XUHV conditions, where residual gas ionization is suppressed. The particle in cell code bender** was used to simulate the injection into the confining fields of the space charge lens in different geometrical configurations and a prototype experiment was constructed consisting of a Gabor lens and an electron source system. In this contribution, simulations and measurements will be presented.
* Schulte, K., et al. Electron cloud dynamics in a Gabor space charge lens. 2012 ** Noll, D., et al. The particle-in-cell code bender and its application to non-relativistic beam transport. 2015 |
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| DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-THPVA005 | |
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| THPVA006 | Space-Charge Compensation in the Transition Area Between LEBT and RFQ | 4425 |
| SUSPSIK061 | use link to see paper's listing under its alternate paper code | |
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Funding: This work is supported by the German Federal Ministry of Education and Research (BMBF) #05P15RFRBA and by HORIZON 2020 for the MYRRHA project #662186 The transition from a space charge compensated beam in the LEBT to an uncompensated beam in the RFQ will influence the beam parameters. To investigate the impact of the electric fields on the space charge compensation, an insulated cone is used as a repeller electrode in front of the RFQ. Depending on the time dependent potential of the RFQ rods respectively to the beam potential, the compensation electrons may be prevented from moving into the RF field which oozes out of the RFQ entrance. The simulation studies are performed with the particle-in-cell code bender*. The simulations may substantiate measurements at the CW-operated RFQ in Frankfurt University** as well as at the foreseen MYRRHA LEBT-RFQ interface.*** In this contribution, a study on a LEBT-RFQ interface is shown. Results of numerical and experimental investigations will be compared. *Noll, D. et al.The Particle-in-Cell Code Bender and Its Application to Non-Relativistic Beam Transport, WEO4LR02, HB'14 **Meusel, O. et al.FRANZ Accelerator Test Bench and Neutron Source.,MO3A03, LINAC'12 ***R. Salemme et al.Design Progress of the MYRRHA Low Energy Beam Line, MOPP137, LINAC'14 |
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| DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-THPVA006 | |
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| THPVA007 | Matching Space-charge Dominated Electron Bunches into the Plasma Accelerator at SINBAD | 4429 |
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| The SINBAD facility (Short and INnovative Bunches and Accelerators at DESY) is foreseen to provide sub-fs to tens of fs electron bunches for Laser Wake-Field Acceleration (LWFA) experiments. In order to avoid emittance growth in plasma cells with ultra-high accelerating gradients the injection and transport of electron bunches with beta functions of mm-size or even smaller are required. This kind of bunch is usually space-charged dominated since the energy is low (< 200 MeV) while the peak current is high for allowing the electron bunches to be used for Free Electron-Laser (FEL) generation. We present the beamline design and explore the possible beam parameters at the SINBAD linac by start-to-end simulations. | ||
| DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-THPVA007 | |
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| THPVA009 | Transverse Beam Dynamics of an 8 MeV Electron Linac | 4432 |
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| The IPM Electron Linac is an 8 MeV (upgradable to 11 MeV) electron linear accelerator under development at the Institute for Research in Fundamental Science (IPM), Tehran, Iran. The linac is mainly regarded as a research project providing hands-on experience in the accelerator science and technology. However, it could serve as an x-ray source or play the injector role for a larger facility. The linac consists of a thermionic gun followed by a travelling wave buncher joined to two accelerating tubes. The transverse focusing is provided by the solenoid mag-nets over the buncher and the accelerating structures. Using the code ASTRA, the transverse beam dynamics is studied and optimized in order to limit the RF emittance. Particularly, the effect of coupler asymmetry is investigated, a beam dynamics design of the solenoid channel is presented, and the effect of the solenoid misalignment on the beam quality is examined. | ||
| DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-THPVA009 | |
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| THPVA011 | Beam Dynamics Studies on Low and Medium Energy Beam Transport With Intense H− Ions for J-PARC Linac | 4439 |
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| Japan Proton Accelerator Research Complex (J-PARC) linac was intensity-upgraded up to pulse current of 50 mA of H− beam by replacing the ion source and the Radio Frequency Quadrupole(RFQ). We measured beam properties at the end of low energy beam transport (LEBT) line test stand under several conditions to investigate the transverse halo and space charge effects of an intense H− ions. The LEBT is composed of two solenoid magnets. Furthermore, space charge neutralization effects in the residual gas were considered into account to describe the behavior of the beam phase space evolution. LEBT transmission efficiency, beam losses were estimated and optimization for beam matching into acceptance of the RFQ is studied. Two-solenoid based LEBT section is connected to the RFQ which is followed by a medium energy beam transport (MEBT) line. In this paper, we discuss the outcomes of beam emittance measurements and the results from beam dynamics simulations throughout LEBT and the RFQ acceleration. | ||
| DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-THPVA011 | |
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| THPVA013 | Benchmarking of the ESS LEBT in TraceWin and IBSimu | 4445 |
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| The modeling of the proton beam in the ESS accelerator starts with a beam distribution as an input to the TraceWin code currently used as the simulation tool. This input is typically a Gaussian distribution, a distribution from other codes, or data from an emittance measurement. The starting point of these simulations is therefore located somewhere along the low energy beam transport (LEBT) close to the ion source. In this paper, we propose to use IBSimu to model the beam extraction from the ion source, which provides an input beam distribution to TraceWin. IBSimu is a computer simulation package for ion optics, plasma extraction, and space charge dominated ion beam transport. We also present a benchmarking of the beam tracking through the LEBT using both these tools, and propose a transition interface to handover the beam distribution from IBSimu to TraceWin. | ||
| DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-THPVA013 | |
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| THPVA019 | Self-consistent Space Charge Tracking Method based on Lie Transform | 4454 |
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| In this paper we propose to describe the self-force of a particles beam, known as space charge, as an Hamiltonan term dependent on the distribution of the particles' coordinates: Hsc = Hsc(ρ(x,y,z)). This Hamiltonian is then used, together with the kinetic component Hk in a Lie transform to generate a transport map by e-L:Hk +Hsc: where the Lie operator :Hk + Hsc: is defined according to the Dragt's notation [1]. Then the Lie transform is used to transport directly the distribution function ρ(x, y, z) in a self-consistent iterative algorithm. The result of this proof-of-concept idea is verified on a drift space and on a FODO channel and compared with a traditional multi-particles simulation code. | ||
| DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-THPVA019 | |
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| THPVA020 | Distribution and Extreme Loss Analysis in the ESS Linac: A Statistical Perspective | 4458 |
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| The report takes a statistical approach in the study of distribution evolution of the proton beam within the ESS linac and reports a new technique of pinpointing the non-linear space-charge effect of the propagating proton beam. By using the test statistic from the nonparametric Kolmogorov-Smirnov test the author visualises the change in the normalised distributions by looking at the supremum distance between the cumulative distribution functions in comparison, and the propagation of the deviation throughout the ESS linac. This approach identifies changes in the distribution which may cause losses in the linac and highlights the parts where the space-charge has big impact on the beam distribution. Also, an Extreme Value Theory approach is adopted in order to quantify the effects of the non linear forces affecting the proton beam distribution. | ||
| DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-THPVA020 | |
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| THPVA086 | Beam Dynamics Studies of an Accelerating Tube for 6 MeV Electron LINAC | 4657 |
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| Side coupled standing wave accelerating tubes are widely used in a low energy linear accelerator because of relatively high accelerating gradient and low sensitivity to construction tolerances. The effective interaction of particles and electromagnetic fields is important for accelerate electrons to intended energy with the greatest efficiency and beam quality output. In this paper, we present the beam dynamics of a 6 MeV Side coupled standing wave accelerating tube using a space charge tracking algorithm (ASTRA). The designed accelerating tube that feeds by a maximum power of 2.6 MW resonant at frequency of 2998.5 MHz in pi/2 mode. 37.5 percent capture efficiency, 6.82 pi-mm-mrad horizontal emittance, 6.78 pi-mm-mrad vertical emittance, 2.24 mm horizontal and vertical beam size and 1079 keV energy spread of the output beam have been determined from the results of beam dynamics studies in ASTRA | ||
| DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-THPVA086 | |
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