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| MOPPC022 | Off-momentum Dynamic Aperture for Lattices in the RHIC Heavy Ion Runs | lattice, luminosity, ion, emittance | 175 |
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Funding: Work supported by Brookhaven Science Associates, LLC under Contract No. DE-AC02-98CH10886 with the U.S. Department of Energy. In this article we calculate and compare the off-momentum dynamic aperture for lattices with different phase advances per FODO cell in the RHIC heavy ion runs. A lattice with an increased phase advance was adopted in 2008-2011 to reduce transverse emittance growth rates from intra-beam scattering. However, during these runs, a large beam loss was observed with longitudinal RF re-bucketing which increased the momentum spread. With operational transverse stochastic cooling in the 2011 RHIC heavy ion run, the transverse intra-beam scattering emittance growth was eliminated, and the beam loss during stores was determined by the off-momentum aperture and burn-off from luminosity. We investigate the possibilities to increase the off-momentum dynamic aperture that would lead to an increase in the integrated luminosity. |
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| MOPPC058 | Eigenmode Computation for Ferrite-loaded Cavity Resonators | cavity, resonance, acceleration, ion | 265 |
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| The GSI Helmholtzzentrum für Schwerionenforschung in Darmstadt is operating the heavy-ion synchrotron SIS18 for fundamental research. Within the ring two ferrite-loaded cavity resonators are installed. During the acceleration phase their resonance frequency has to be adjusted to the revolution frequency of the heavy-ions to reflect their increasing velocity. Within the resonator structures dedicated biased ferrite rings are installed. In the whole setup a properly chosen bias current is used to modify the differential permeability of the ferrite material which consequently enables to adjust the eigenfrequency of the resonator system. The goal of the current study is to numerically determine the lowest eigensolutions of accelerating ferrite-loaded cavities based on the Finite Integration Technique. Since the underlying eigenmodes depend on the differential permeability, the static magnetic field generated by the bias current has to be computed in a first step. The eigenmodes can then be determined with the help of a dedicated Jacobi-Davidson eigensolver. Particular emphasis is put on the implementation to enable high performance computations based on distributed memory machines. | |||
| MOPPD009 | Stochastic Cooling Developments for HESR at FAIR | target, ion, emittance, scattering | 388 |
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| The High-Energy Storage Ring (HESR) is part of the upcoming International Facility for Antiproton and Ion Research (FAIR) at GSI in Darmstadt. The HESR is planned to dedicate to the field of high-energy antiproton physics to explore the research areas of charmonium spectroscopy, hadronic structure, and quark-gluon dynamics with high-quality beams over a broad momentum range from 1.5 to 15 GeV/c. The new facility provides the combination of powerful phase-space cooled antiproton beams and internal Pellet and gas jet targets to achieve the requirements of the experiment PANDA in terms of beam quality and luminosity. Detailed theoretical analyses have been carried out to design the stochastic cooling system for accumulation and stochastic cooling of antiprotons with target operation. Recently it is proposed to utilize the HESR also for the atomic and nuclear physics with highly charged heavy ions such as 132Sn50+ in the dedicated experiments at high energies 0.74-3 GeV/u. In this contribution the feasibility of stochastic cooling of heavy ions with internal targets is in detail investigated under the constraint of the cooling system hardware as foreseen for anti-proton cooling. | |||
| MOPPD030 | Present Status of RIKEN Ring Cyclotron | ion, cyclotron, linac, vacuum | 433 |
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| The RIKEN Ring Cyclotron (RRC K540) has been in stable operation over twenty-five years, and supplying many kinds of heavy-ion beams to experiments. Since 2007, it has also been supplying beams to the RIBF four Ring cyclotrons including the Super-conducting Ring Cyclotron (SRC K2500). Now the RRC has three kinds of injectors, one is K70 AVF cyclotron for light ions, the second is the variable-frequency linac for heavy ions, and the third is the RILAC2 for using the high intensity very heavy ions like U and Xe. The many combinations of accelerators are possible, and in any acceleration modes, the RRC should works as a first energy booster. A total operation time of the RRC is more than 5000 hr in every year. The present status of the RRC operation will be reported. | |||
| MOPPD070 | A SVD-based Orbit Steering Algorithm for RHIC Injection | injection, ion, proton, controls | 523 |
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Funding: Work supported by Brookhaven Science Associates, LLC under Contract No. DE-AC02-98CH10886 with the U.S. Department of Energy. The RHIC physics programs involve experiments with polarized proton and several species of ion beams. In the past, when switching between physics programs, first turn and circulating beam in RHIC was established manually by adjustments to the corrector dipoles for minimum beam loss. In this report, we introduce a new steering scheme based on an SVD algorithm which uses a single-pass orbit response matrix for first turn steering. The new scheme was implemented into the controls system and demonstrated successfully in Run-11. Establishing circulating beam using this automated approach has been shown to dramatically reduce the beam setup time. |
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| WEPPC018 | Design of a Spoke Cavity for RIKEN RI-beam Factory | cavity, vacuum, ion, simulation | 2245 |
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| Designs of a CW superconducting rebuncher tri-spoke cavity for uranium beams with β = 0.303 has been studied. The estimated peak voltage is rather high as 3 mega-voltages (MV). The resonator frequency was chose as 219MHz which is 12 times of the foundational frequency. The buncher would be settled in a location between two booster cyclotrons (RRC: K = 540MeV, fRC: K = 570 MeV). In this cavity design, a flat E field distribution on beam axis was designed based on the Microwave Studio (MWS) simulations. The cavity parameters, detail designs and some simulated results will be reported in this paper. | |||
| WEPPD028 | Collimators and Materials for High Intensity Heavy Ion Synchrotrons | ion, simulation, proton, collimation | 2564 |
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Funding: Funded by EU FP7 WP8 ColMat and Federal Republic of Germany The operation of high power high brightness accelerators requires huge efforts for beam cleaning and machine protection. Within the WP 8 (ColMat)of the EU research framework EuCARD we investigate new materials and methods for beam collimation and machine protection. TWe present an overview of these activities at the GSI Helmholtzzentrum für Schwerioneforschung in Darmstadt. Simulations of accidental beam losses in LHC and SIS100 have been performed. Scenarios for halo collimation of heavy ions and protons in SIS100 routine operation have been investigated. A prototype of a cryogenic collimator for charge exchange losses during intermediate charge state heavy ion operation in SIS100 has been build and tested with beam. Several candidates of advances composite materials for collimation system upgrades of present and construction of future high power accelerators have been irradiated and their properties are being characterized. Most deliverables and milestones of the R&D programm have already been reached before the end of the funding period. A summary of the obtained results will be presented. |
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| WEPPR003 | Longitudinal Dynamics of Intense Heavy-Ion Bunches in SIS-100 | impedance, space-charge, ion, beam-loading | 2937 |
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| In the SIS-100 highest heavy-ion intensities have to be accelerated to deliver beam to the FAIR experiments. In the projected SIS-100 synchrotron the heavy ion bunches will be strongly affected by the longitudinal space charge force. Due to the limited RF bucket area all mechanisms which might cause longitudinal phase space dilution must be understood and controlled. Space charge effects, like the reduction in the RF voltage and the loss of Landau damping, have already been part of elaborate studies. It has been shown that cavity beam loading can deform the flattened bunch shape in the dual rf bucket. Among the different counter measures an inductive insert has been proposed in order to partially compensate the longitudinal space charge impedance. Optimized settings for the difference between the two rf phases in a dual rf bucket might be an option to reduce the effect of beam loading. In this contribution we will analyse the matched bunch distribution for SIS-100 parameters in single and dual rf buckets. Analytical and numerical studies of the interplay of longitudinal space charge, cavity beam loading and an inductive insert will be presented. | |||
| THEPPB004 | Development of a Cryocatcher-System for SIS100 | ion, vacuum, simulation, cryogenics | 3237 |
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Funding: Work supported by EU (FP7 workpackage COLMAT) and GP-HIR – Graduate Program for Hadron and Ion Research at GSI. The main accelerator SIS100 of the FAIR-facility will provide heavy ion beams of highest intensities using intermediate charge state heavy ions. Ionization beam loss is the most important loss mechanism, therefore, a special synchrotron layout has been developed, which includes a dedicated cold ion catcher system which provides almost hundred percent catching efficiency. Dynamic vacuum effects are suppressed effectively by means of special low desorption yield surfaces. A prototype of the cryocatcher system has been developed, constructed and tested with heavy ion beam from SIS18. It is a work package of the EU-FP-7 project COLMAT. Results from these tests are presented as well as implications for the production of the 60 SIS100 cryocatchers. |
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| THPPP001 | High Intensity Intermediate Charge State Heavy Ions in Synchrotrons | injection, ion, septum, emittance | 3719 |
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| In order to reach the desired FAIR intensities for heavy ions, SIS18 and SIS100 have to be operated with intermediate charge states. Operation with intermediate charge state heavy ions at the intensity level of about 1011 ions per cycle has never been demonstrated elsewhere and requires a dedicated machine design. After partially completing the upgrade program of SIS18, the number of intermediate charge state heavy ions accelerated to the FAIR booster energy of 200 MeV/u, could be increased by a factor of 70. The specific challenge for the SIS18 and SIS100 booster operation is the high cross section for ionization of the intermediate charge state heavy ions, in combination with gas desorption processes and the dynamic vacuum pressure. The achieved progress in minimizing the ionization beam loss underlines that the chosen technical strategies described in this report are appropriate. The latest intensity records and results from the machine development programs are presented. | |||
| THPPP029 | Simultaneous Global Coupling and Vertical Dispersion Correction in RHIC | coupling, quadrupole, proton, polarization | 3794 |
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Funding: Work supported by Brookhaven Science Associates, LLC under Contract No. DE-AC02-98CH10886 with the U.S. Department of Energy. Residual vertical dispersion on the order of ±0.2 m (peak to peak) has been measured at store energies for both polarized proton and heavy ion beams. The hypothesis is that this may have impact on the polarization transmission efficiency during the energy ramp, the beam lifetimes, and, especially for heavy ions, the dynamics aperture. An algorithm to correct global coupling and dispersion simultaneously using skew quads was developed for RHIC. Simulation results together with the measured coupling and dispersion functions before and after correction will be shown for both injection and store together with an assessment of overall collider performance improvement. |
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| THPPP032 | Advanced Layout Studies for the GSI CW-Linac | linac, solenoid, cavity, ion | 3803 |
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Beam dynamics studies were made with the LORASR code for the planned superconducting (sc)continuous wave (cw) linear accelerator. It comprises a fixed accelerating part with an output energy of 3.5 MeV/u at a design mass/charge ratio of 6 and an energy variable part with an output energy of up to 7.3 MeV/u. The general layout, which provides for nine cavities combined with seven separate solenoids for a total length of 12.7 m, is based on a basic design by A. Minaev*. The recent studies show the parameter study for output energy variation. The statistical rotational and transverse offset error calculations illuminate the tolerances for acceptable errors. These are particularly relevant in the beam dynamics within a superconducting environment. Further calculations focus on varying the charge-to-mass ratio to reach linac energies up to 10 MeV/u, meeting the requirements of future UNILAC experiments.
*A. Minaev et al., “Superconducting, energy variable heavy ion linac with constant beta, multicell cavities of CH-type,” PRST-AB 12, 120101 (2009). |
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| THPPP096 | Recent Developments and Applications of the Beam Simulation Code Warp | plasma, simulation, diagnostics, ion | 3957 |
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Funding: Supported by US-DOE Contracts DE-AC02-05CH11231 and DE-AC52-07NA27344. Used resources of NERSC, supported by US-DOE Contract DE-AC02-05CH11231. The Particle-In-Cell Framework Warp is being developed by the Heavy Ion Fusion US program to guide the development of accelerators for high energy density experiments and ultimately for inertial fusion energy. Accurate predictions of the beam phase space are important for understanding the limits to the pulse compression, in particular for NDCX-II now under construction at LBNL. We will present a new numerical method that correct for the effects of linear correlations, offering accurate mapping of energy spread and temperature. The interaction of the beam with the neutralizing plasma can affect non linearly the phase space of the beam. We will present fully kinetic simulation of the beam/plasma interaction aimed toward a better understanding of these effects and possibilities for mitigating or exploiting them. We will also present an application of the original warped coordinate algorithm to the modeling of charge separation in the transition of a 50 MeV singly charged Uranium beam to higher charge state upon passing through a stripping foil, with the goal of decreasing the cost of a Heavy Ion Fusion driver. We also describe studies of beams in plasmas and of injector optimization. Used resources of NERSC. |
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| THPPR047 | Design of Superconducting Rotating-gantry for Heavy-ion Therapy | superconducting-magnet, simulation, ion, optics | 4080 |
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| We designed a superconducting rotating-gantry for heavy-ion therapy. This isocentric rotating-gantry can transport heavy ions having 430 MeV/u to the isocenter with irradiation angles between 0-360 degrees, and further has the capability of our fast raster-scanning irradiation, as employed in the existing fixed-irradiation-ports. For the magnets, combined-function superconducting-magnets will be employed. The use of these superconducting magnets allowed us to design the compact gantry, while keeping a sufficient scan size at the isocenter; the length and radius of the gantry would be approximately 13m and 5.5m, respectively, which are comparable to those of the existing proton gantries. Superconducting coils were designed by using the 3D field solver, so as to obtain uniform field distributions. The two superconducting magnets are being constructed. We will present the design of the superconducting gantry as well as details of the superconducting magnets. | |||