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MOPCH092 | CRYRING Machine Studies for FLAIR | CRYRING, ion, antiproton, proton | 249 | ||||
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At the FLAIR facility (Facility for Low-energy Antiproton and Ion Research) at FAIR, antiprotons and heavy ions will be decelerated to very low energies and ultimately to rest. One step in this deceleration is made in the magnetic storage ring LSR (Low-Energy Storage Ring). CRYRING at the Manne Siegbahn Laboratory in Stockholm will be closed down within the next few years, and since CRYRING has an energy range quite similar to the proposed LSR, is equipped with beam cooling, and has several other features required for a deceleration ring, plans are being made for the transfer of CRYRING to FAIR and for its use as the LSR ring. This paper describes some of the characteristics of CRYRING relevant for its new role, modifications that need to be made, and test that have been performed at CRYRING with, e.g., deceleration of protons from 30 MeV to 300 keV kinetic energy, which is the proposed energy range for antiprotons at LSR.
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MOPCH109 | Design Studies on a Novel Stellarator Type High Current Ion Storage Ring | ion, injection, plasma, kicker | 297 | ||||
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A high current storage ring for the accumulation of ion beams provided by a new 150 kV terminal is under consideration at the Frankfurt University. The configuration based on a toroidal magnetic field seems promising for the storage of intense low energy ion beams, especially when concerning the various potential concepts for space charge compensation. The theory of plasma confinement on magnetic surface is transformed to numerical simulations on circulating ion beams. The space charge effects and stability conditions are studied and will be presented. Various injection techniques based on crossed field-drifts are investigated. Accordingly test experiments are prepared based on two 30 degree toroidal sectors at a major radius of 1.3m with a maximum toroidal magnetic field of 0.6T on axis.
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MOPCH115 | Transverse Space Charge Studies for the ISIS Synchrotron | resonance, synchrotron, simulation, focusing | 312 | ||||
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The ISIS Facility at the Rutherford Appleton Laboratory in the UK produces intense neutron and muon beams for condensed matter research. It is based on a 50 Hz proton synchrotron which, once the commissioning of a new dual harmonic RF system is complete, will accelerate about 3.5·1013 protons per pulse from 70 to 800 MeV, corresponding to mean beam powers of 0.2 MW. Following this upgrade, transverse space charge is expected to be one of the main intensity limitations, and is also a key factor for further machine upgrades. A programme of R&D on transverse space charge is now under way, aiming not only to improve the ISIS ring but also to exploit it as an experimental tool for testing theory and codes. This paper summarises work so far, outlining calculations for coherent envelope modes on ISIS, using numerical solutions of the envelope equation to show the expected behaviour near half integer resonance. Progress on work linking these predictions with more realistic beam models in space charge codes, and extending calculations to images, coupling and non linear resonances will be described. Plans and preparations for experiments, along with initial results, will also be presented.
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MOPLS138 | Space Charge and Equilibrium Emittances in Damping Rings | emittance, damping, lattice, radiation | 882 | ||||
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The unusual combination of small beam size and long ring circumference may cause space charge to have noticeable effects on the beam dynamics of the ILC (International Linear Collider) damping rings. One possible consequence is a modification of the vertical equilibrium emittance resulting from a non-ideal lattice. One simple way to account for this effect is to model space charge in the linear approximation within the framework of Oide's envelope (or Chao's matrix) formalism, whis is commonly used to calculate equilibrium emittances in lepton storage rings. However, this model would likely overestimate the effect as a linear approximation for space charge is accurate only in a small neighborhood of a bunch center. For a more accurate modelling, we propose to make use of Sacherer's envelope equations consisting of a closed set of equations for the second moments of a beam distribution that account for the nonlinear dependence of the space-charge force. Here we will illustrate how Sacherer's equations can be combined with Oide's formalism and apply the result to the ILC damping rings.
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TUPCH036 | Modelling of Diagnostics for Space Charge Studies on the ISIS Synchrotron | ion, simulation, proton, synchrotron | 1082 | ||||
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The ISIS Facility at the Rutherford Appleton Laboratory in the UK produces intense neutron and muon beams for condensed matter research. It is based on a 50 Hz proton synchrotron which, once the commissioning of a new dual harmonic RF system is complete, will accelerate about 3.5·1013 protons per pulse from 70 to 800 MeV, corresponding to mean beam powers of 0.2 MW. Transverse space charge is a key issue for both present and proposed upgrades to the machine, and is the focus of current R&D studies. Experiments on the ISIS ring are central to this work, therefore understanding and quantifying limitations in present and proposed diagnostics is essential. This paper presents work studying and modelling the ISIS residual gas profile monitors, including the effects of non-uniformity in sweep fields, space charge and images. Progress on related work looking at other important diagnostics, e.g., position and envelope monitoring, will also be summarised.
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TUPCH039 | A Phase Space Tomography Diagnostic for Pitz | quadrupole, diagnostics, PITZ, gun | 1091 | ||||
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The Photo Injector Test Facility at DESY in Zeuthen (PITZ) is a European collaboration developing RF photocathode electron guns for light source and linear collider projects. As part of the collaborative work being partially funded by the EU's FP6 programme, CCLRC Daresbury Laboratory and DESY are designing and building a phase space tomography diagnostic based on a set of multiple quadrupoles and view screens. In order to measure the beam emittance, four screens with intermediate quadrupole doublets will be used. The equipment will be installed and tested at PITZ as part of the facility upgrade presently ongoing. Following simulations of the gun using the ASTRA code at a range of energies, simulations of the electron beam parameters through the matching and tomography sections must be undertaken in order to specify the optimum arrangement of magnets and screens.
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TUPCH065 | A Prototype of Residual Gas Ionization Profile Monitor for J-PARC RCS | electron, ion, IPM, MCP | 1163 | ||||
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A prototype of a residual gas ionization profile monitor (IPM) for J-PARC RCS has been developed. It consists of electrodes producing electric field to collect ionized ions/electrons, MCP as a signal read-out device, an electron generator to evaluate the gain balance of MCP channels, and a wiggler type magnet producing guiding field. The monitor has been installed in KEK-PS main ring and has been examined using proton beam. At the conference, recent preliminary results of experiments will be reported.
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TUPCH072 | New Generation Streak Camera Design and Investigation | electron, radiation, monitoring, simulation | 1175 | ||||
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The only method for electron bunch duration monitoring with a resolution in the order of 10 fs and less is the method of photochronography of the bunch incoherent radiation in the frequency range, for example, of visible light and at realizing streak camera with new principles of its operation*. In the paper the streak camera design for measuring both the electron bunches and x-ray pulses duration with the mentioned temporal resolution is presented. The results of the camera investigation, with photoelectron dynamics simulation taking into account space-charge effect and impact of the surface roughness of a spherical photocathode of the 20-50 micrometers radius (forming a modulating gap of spherical configuration) on the camera resolution, are presented and discussed.
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*A. M. Tron and I. G. Merinov. Method of bunch radiation photochronography with 10 femtosecond and less resolution. http://www.physics.ucla.edu/PAHBEB2005/talks/10oct2005/wg2/atron.pdf |
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TUPLS043 | Simulations for the Frankfurt Funneling Experiment | simulation, emittance, rfq, linac | 1591 | ||||
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Beam simulations for the Frankfurt Funneling Experiment are done with RFQSim and FUSIONS. RFQSim is responsible for the beam transport through an RFQ accelerator. Behind the accelerator the particle dynamic program FUSIONS calculates the macro bunches of both beam lines through an r.f. funneling deflector. A new space charge routine has now been included. The status of the development of FUSIONS and the results of the simulations will be presented.
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TUPLS082 | The Frankfurt Neutron Source at the Stern-Gerlach-Zentrum (FRANZ) | linac, proton, target, GSI | 1690 | ||||
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About 40ns long proton pulses with an energy of 120keV and currents of up to 200mA will be produced at the 150kV high current injector with a rep.rate of up to 250kHz. The main acceleration will be done by a 175MHz-RFQ. After this section the proton bunches will have an energy of about 1.7MeV. A 4-gap cavity will allow for an energy increase up to 2.2MeV.In order to get 1ns short pulses at the Li-7-Target we propose a buncher-system of the Mobley-Type*, whereby periodic deflection at one focus of a dipole-magnet guides the bunche train from the linac on different paths to the other focus, where the n-production traget is located in the time focus.By 7Li(p,n)B·107 reactions low-energy neutron bunches will be produced with an averaged integrated flux-density of 4*107/(cm2 s) at a distance of 0.4m. The upper limit for the neutron spectra will be 500keV. The main challange with respect to this buncher is the strong space charge action, which has to be treated by careful particle simulations. FRANZ is among other duties well suited for (n,gamma)-cross-sectional measurements with astrophysical relevance**/***. It is characterised by high n-intensities and by its pulse-structure.
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*Phys. Rev. 88(2), 360-361 (1951). **Phys. Rev. C 71, 025803 (2005).***Phys. Rev. Lett. 94, 092504 (2005). |
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TUPLS090 | LEBT Simulations and Ion Source Beam Measurements for the Front End Test Stand (FETS) | ion, emittance, ion-source, simulation | 1714 | ||||
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The Front End Test Stand (FETS) at the Rutherford Appleton Laboratory (RAL) is intended to demonstrate the early stages of acceleration (0-3MeV) and beam chopping required for high power proton accelerators, including proton drivers for pulsed neutron spallation sources and neutrino factories. Optimisation of the beam focussing within the Low Energy Beam Transport (LEBT) is necessary to minimise beam losses upon acceleration within the FETS RadioFrequency Quadrupole (RFQ). Simulations of the LEBT are currently under way using the General Particle Tracer package (GPT). Previous envelope calculations suggest weak and strong focussing solutions for the LEBT solenoids. Definitive beam dynamics simulations in GPT require further measurements of the transverse emittances and beam profile of the ion source beam, due to the sensitivity of the simulations on the initial beam profile and level of space charge compensation. A pepperpot emittance/profile measurement system has been designed for use on the ISIS ion source development rig. Results from this pepperpot system are used to constrain the initial conditions for the GPT simulations.
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TUPLS115 | Transverse Phase Space Painting for the CSNS Injection | injection, emittance, simulation, lattice | 1774 | ||||
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The CSNS accelerators consist of an 80 MeV proton Linac, and a 1.6 GeV rapid cycling synchrotron (RCS). The ring accumulates 1.88*1013 protons via H-stripping injection in the phase CSNS-I. The injected beam is painted into the large transverse phase space to alleviate space-charge effects. The uniformity of beam emittance is important in reducing the tune shift/spread due to space charge effect. The paper introduces two parameters to evaluate the uniformity of a distribution. To satisfy the low-loss design criteria, extensive comparison of different painting scenarios has been carried out by using the simulation code ORBIT. This paper gives detailed studies on painting schemes and the dependence on the lattice tune, the injection peak current, and also chopping rate.
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WEOBPA03 | 1.8 MW Upgrade of the PSI Proton Facility | cyclotron, target, simulation, extraction | 1879 | ||||
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The PSI proton accelerator delivers currently a 590 MeV beam with an intensity of 2 mA. The upgrade programme aiming at boosting the beam power from 1.2 to 1.8 MW includes the ongoing installation of new bunchers in the transfer lines to the injector cyclotron and between injector and ring cyclotron, the replacement of the Al-cavities of the ring cyclotron by Cu-cavities operated at 1 MV, and the design and future installation of additional accelerating cavities in the injector cyclotron. Simulation studies are under way to improve our understanding of the space charge effects at the different stages of acceleration. The present status of the project will be presented.
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Transparencies
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WEXFI01 | Instabilities and Space Charge Effects in High Intensity Ring Accelerators | damping, impedance, dipole, simulation | 1882 | ||||
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This presentation will review beam dynamics in circular accelerators with high beam intensity and space charge effects. The main focus will be on recent theoretical and experimental results related to collective instabilities and resonance crossing with space charge. In the first part of the presentation, the effect of space charge on collective instability thresholds and impedance budgets will be discussed. In this context the effect of space charge induced mode coupling on the longitudinal microwave instability will be illustrated. The stability of longitudinal bunched beam modes and of transverse dipole modes in the presence of space charge will be discussed. Recent work related to the transverse mode coupling instability (TMCI) with space charge will be reviewed. In the second part of the presentation, "incoherent" space charge effects on transverse nonlinear dynamics issues, like nonlinear resonance crossing, will be reviewed.
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Transparencies
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WEYFI01 | Modelling of Space Charge and CSR Effects in Bunch Compressor Systems | CSR, simulation, emittance, radiation | 1897 | ||||
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Bunches with high peak currents of the order of kilo-Amperes are required in linac based X-ray free electron lasers. These bunches cannot be produced directly in guns because space charge forces would destroy the brilliance within a short distance. Therefore bunches with a peak current of a few tens of Amperes are created in laser-driven radio-frequency sources and are compressed in length by two orders of magnitude. In most designs, the compression is achieved in magnet chicanes, where particles with different energies have different path lengths so that a bunch with an energy distribution correlated with longitudinal particle position can shrink in length. The principle problem is that short bunches on curved trajectories will emit coherent synchrotron radiation (CSR). The CSR effects and the space charge fields play an important role in the particle dynamic and the design of a bunch compression system. This presentation will provide an overview of computational methods and simulation tools for space charge and coherent synchrotron radiation effects in magnetic bunch compression systems.
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Transparencies
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WEPCH054 | Matrix Formalism for Current-independent Optics Design | focusing, emittance, optics, cathode | 2044 | ||||
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Matrix formalism has been a powerful tool for beam optics designs. It not only facilitates computations but also plays an important role in formulating various design concepts. Here we extend the standard matrix formalism for the purpose of designing an optics that transports space-charge-dominated intense beam. Furthermore, we explore the concept of current-independent optics, which can be useful for systems such as high-brightness injectors and space-charge-dominated rings. Our discussion here is preliminary and limited to axisymmetric systems.
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WEPCH079 | Effects of Intrinsic Nonlinear Fields in the J-PARC RCS | resonance, sextupole, simulation, injection | 2104 | ||||
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In order to accelerate a high intense proton beam with small particle losses, the J-PARC RCS, which is being constructed at JAEA, has a large acceptance. In such synchrotrons, the nonlinear motion of the beam particles, especially moving away from the axis of the elements, is a common issue, and it becomes essential to consider intrinsic field nonlinearities. The main sources of nonlinear magnetic fields in the RCS are as follows: fringes of the main dipole and quadrupole magnets, sextupole fields used for the chromatic correction, leak fields from the injection and extraction beam lines, etc. In this paper, we will discuss influences of the intrinsic field nonlinearities and a cure for the induced betatron resonances, based on single-particle and multi-particle tracking simulations.
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WEPCH080 | Beam Simulation of SQQ Injection System in KIRAMS-30 Cyclotron | cyclotron, injection, ion-source, simulation | 2107 | ||||
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The injection system of KIRAMS-30 cyclotron consists of a double gap buncher, an SQQ, and a spiral inflector. Initial beam with 100 mmmrad has been generated by random Gaussian function in the transverse plane and random uniform function in the longitudinal direction. Using the 3D electric and magnetic fields of a buncher, SQQ, inflector, and return-yoke bore, the characteristics of the beam injected into the KIRAMS-30 cyclotron's central region has been obtained. This paper presents the results of its beam characteristics and parameters of each beam element.
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WEPCH081 | Injection of The Proton Beam Into The Compact Cyclotron with Solenoid | cyclotron, injection, simulation, emittance | 2110 | ||||
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The proton (H-) low (100 mkA) intensity beam injected by means of the solenoid comes to the first cyclotron orbit without the beam emittance deterioration. This is demonstrated by computer simulation.
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WEPCH106 | Stationary Beam Electron Transport in AIRIX for the TRAJENV Code | electron, induction, focusing, target | 2161 | ||||
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In the framework of the AIRIX program, the electron beam propagation between the injector and the X-conversion target is routinely simulated with the 2D TRAJENV code. We describe the physical models implemented in the code for a intense stationary beam. We present both the modeling of applied electromagnetic forces in induction cells and self generated ones. To avoid the cell damage due to target debris generated by the electron beam impact, a thin debris shield has been tested upstream the X-ray converter. Such a thin foil located in the beam pass, is taken into account in TRAJENV. We describe the modeling and the influence of the foil on the beam.
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WEPCH118 | LORASR Code Development | linac, rfq, simulation, proton | 2194 | ||||
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LORASR is specialized on the beam dynamics design of Separate Function DTL's based on the 'Combined 0 Degree Structure (KONUS)' beam dynamics concept. The code has been used for the beam dynamics design of several linacs already in operation (GSI-HLI, GSI-HSI, CERN Linac 3, TRIUMF ISAC-I) or scheduled for the near future (Heidelberg Therapy Injector, GSI Proton Linac). Recent code development was focused on the implementation of a new PIC 3D FFT space charge routine, facilitating time-efficient simulations with up to 1 million macro particles routinely, as well as of tools for error study and loss profile investigations. The LORASR code was successfully validated within the European HIPPI Project activities: It is the Poisson solver benchmarking and the GSI UNILAC Alvarez section tracking comparison programme. The error study tools are a stringent necessity for the design of future high intensity linacs. The new LORASR release will have a strong impact on the design of the GSI FAIR Facility Proton Linac, as well as the transmission investigations on the IFMIF Accelerator. This paper presents the status of the LORASR code development and the benchmarking results.
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WEPCH120 | Simulation of 3D Space-charge Fields of Bunches in a Beam Pipe of Elliptical Shape | ASTRA, simulation, DESY, damping | 2200 | ||||
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Recent applications in accelerator design require precise 3D calculations of space-charge fields of bunches of charged particles additionally taking into account the shape of the beam pipe. An actual problem of this kind is the simulation of e-clouds in damping rings. In this paper a simulation tool for 3D space-charge fields is presented where a beam pipe with an arbitrary elliptical shape is assumed. The discretization of the Poisson equation by the method of finite differences on a Cartesian grid is performed having the space charge field solved only in the points inside the elliptical cross-section of the beam pipe taking care of the conducting boundaries of the pipe. The new routine will be implemented in the tracking code ASTRA. Numerical examples demonstrate the performance of the solution strategy underling the new routine. Further tracking results with the new method are compared to established space-charge algorithms such as the FFT-approach.
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WEPCH121 | 3D Space-charge Calculations for Bunches in the Tracking Code ASTRA | ASTRA, DESY, electron, simulation | 2203 | ||||
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Precise and fast 3D space-charge calculations for bunches of charged particles are of growing importance in recent accelerator designs. One of the possible approaches is the particle-mesh method computing the potential of the bunch in the rest frame by means of Poisson's equation. In that, the charge of the particles are distributed on a mesh. Fast methods for solving Poisson's equation are the direct solution applying Fast Fourier Methods (FFT) and a finite difference discretization combined with a multigrid method for solving the resulting linear system of equations. Both approaches have been implemented in the tracking code ASTRA. In this paper the properties of these two algorithms are discussed. Numerical examples will demonstrate the advantages and disadvantages of each method, respectively.
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WEPCH141 | Accelerator Physics Code Web Repository | simulation, electron, CERN, site | 2254 | ||||
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In the framework of the CARE HHH European Network, we have developed a web-based dynamic accelerator-physics code repository. We describe the design, structure and contents of this web repository, illustrate its usage, and discuss our future plans.
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WEPLS018 | Optics for Phase Ionization Cooling of Muon Beams | emittance, focusing, collider, resonance | 2430 | ||||
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The realization of a muon collider requires a reduction of the 6D normalized emittance of an initially generated muon beam by a factor of more than 106. Analytical and simulation studies of 6D muon beam ionization cooling in a helical channel filled with pressurized gas or liquid hydrogen absorber indicate that a factor of 106 is possible. Further reduction of the normalized 4D transverse emittance by an additional two orders of magnitude is envisioned using Parametric-resonance Ionization Cooling (PIC). To realize the phase shrinkage effect in the parametric resonance method, one needs to design a focusing channel free of chromatic and spherical aberrations. We report results of our study of a concept of an aberration-free wiggler transport line with an alternating dispersion function. Resonant beam focusing at thin beryllium wedge absorber plates positioned near zero dispersion points then provides the predicted PIC effect.
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THPCH004 | Space Charge Induced Resonance Trapping in High-intensity Synchrotrons | beam-losses, resonance, synchrotron, scattering | 2790 | ||||
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With the recent development of high-intensity circular accelerators, the simultaneous presence of space charge and lattice nonlinearities has gained special attention as possible source of beam loss. In this paper we present our understanding of the role of space charge and synchrotron motion as well as chromaticity for trapping of particles into the islands of nonlinear reonances. We show that the three effects combined can lead to significant beam loss, where each individual effect leads to small or negligible loss. We apply our findings to the SIS100 of the FAIR project, where the main source of field nonlinearities stems from the pulsed super-conducting dipoles, and the beam dynamics challenge is an extended storage at the injection flat-bottom, over almost one second, together with a relatively large space charge tune shift.
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THPCH008 | The Non-linear Space Charge Field Compensation of the Electron Beam in the High Energy Storage Ring of FAIR | electron, antiproton, multipole, resonance | 2802 | ||||
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In the High Energy Storage Ring, a part of the FAIR project at GSI in Darmstadt, the internal target is used. To compensate the interaction of the beam with the target, the electron beam cooling is needed. However, together with the cooling, the non-linear space charge field of electron beam modifies the dynamic aperture. We investigate the possible schemes of this effect compensation using the multi-pole correctors on the HESR.
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THPCH010 | Electron Beam-laser Interaction near the Cathode in a High Brightness Photoinjector | laser, electron, cathode, emittance | 2805 | ||||
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The production of high charge short bunches in a high brightness photoinjector requires laser pulses driving the cathode with GW range peak power on a mm spot size. The resulting transverse electric field experienced by the electron beam near the cathode is of the order of 200-500 MV/m, well in excess of a typical RF accelerating field of 50-100 MV/m. We present here an analytical and computational study of the resultant beam dynamics. Simulations including the electron beam-laser interaction have been performed with the code HOMDYN taking into account the superposition of incident and reflected laser pulses as well as space charge fields. Under this conditions the emittance degradation is negligible, as predicted by analytical methods, but a longitudinal charge modulation occurs on the scale of the laser wavelength, in case of oblique incidence, driven by the longitudinal component of the laser field. Preliminary simulations up to the photoinjector exit show that charge modulation is transformed into energy modulation via the space charge field, which may produce enhanced microbunching effects when the beam is further compressed in a magnetic chicane.
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THPCH013 | Study of Particle Losses Mechanism for J-PARC Main Ring | resonance, injection, sextupole, emittance | 2811 | ||||
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Detailed understanding as well as confidence in simulation modeling of long-term effects (~ 100'000 turns) of high intensity proton beam is crucial for Main Ring (MR) of the J-PARC project, where it is necessary to hold the high-intensity beam over typically ~ 2 sec with a loss level less than 1%. The major focus of such study is the combined effect of space charge and nonlinear resonances and its impact on halo formation and/or beam loss. In frame of this report, the tracking results for the injection process including realistic representation of the ring's focusing structure are discussed. Optimization of the working point during the injection process is presented. The halo formation and particle losses during the injection and acceleration for MR have been estimated for realistic magnetic field errors.
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THPCH015 | Matched and Equipartitioned Method for High-intensity RFQ Accelerators | rfq, emittance, resonance, linac | 2814 | ||||
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Maintaining beam envelope match, avoiding structure resonances, and using an equilibrium (equipartitioned) energy balance within the beam are the primary methods for preventing emittance growth and halo formation in high current linacs. A design strategy that requires the RFQ accelerator to be matched and equipartitioned over most of its length will produces very robust designs under a wide variety of conditions, the beam with proper energy balance is also inherently stable against resonances near the operation point. Based on this strategy, a new dynamics method is proposed to avoid the envelope mismatch and energy imbalance between different degrees of freedom. The beam sizes are well confined to match the accelerating channel in this method, to minimize the emittance growth and the related beam loss. Following the method, a RFQ design code named MATCHDESIGN has been written at Peking University. A test design of 50mA proton RFQ operating at 350 MHz was given to prove this method and it resulted in a good dynamics design.
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THPCH024 | An Efficient Formalism for Simulating the Longitudinal Kick from Coherent Synchrotron Radiation | CSR, synchrotron, synchrotron-radiation, simulation | 2829 | ||||
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Coherent Synchrotron Radiation (CSR) can severely limit the performance of planned light sources and storage rings which push the envelope to ever higher bunch densities. In order to better simulate CSR, the formalism of Saldin is extended to work at lower energies and shorter length scales. The formalism is also generalized to cover the case of an arbitrary configuration of multiple bends.
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*E. L. Saldin et al. Nucl. Instrum. Methods Phys. Res., Sect. A 398, 373 (1997). |
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THPCH026 | Parallel 3-D Space Charge Calculations in the Unified Accelerator Library | simulation, synchrotron, AGS, instrumentation | 2835 | ||||
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The paper presents the integration of the SIMBAD space charge module in the UAL framework. SIMBAD is a Particle-in-Cell (PIC) code. Its 3-D parallel approach features an optimized load balancing scheme based on a genetic algorithm. The UAL framework enhances the SIMBAD standalone version with the interactive ROOT-based analysis environment and an open catalog of accelerator algorithms. The composite package addresses complex high intensity beam dynamics studies and has been developed as a part of the FAIR SIS 100 project.
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THPCH047 | Maps for Electron Clouds: Application to LHC | electron, simulation, LHC, CERN | 2889 | ||||
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Electron Cloud studies performed so far were based on very heavy computer simulations taking into account photoelectron production, secondary electron emission, electron dynamics, and space charge effects providing a very detailed description of the electron cloud evolution. In a recent paper* it has been shown that, for the typical parameters of RHIC, the bunch-to-bunch evolution of the electron cloud density can be represented by a cubic map. Simulations based on this map formalism are orders of magnitude faster than those based on usual codes. In this communication we show that the map formalism is also reliable in the range of typical LHC parameters, and discuss the dependence of the polynomial map coefficients on the physical parameters affecting the electron cloud (SEY, chamber dimensions, bunch spacing, bunch charge, etc.).
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*U. Iriso and S. Peggs. "Maps for Electron Clouds", Phys. Rev. ST-AB 8, 024403, 2005. |
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THPCH060 | Simulation Study on the Energy Dependence of the TMCI Threshold in the CERN-SPS | electron, simulation, impedance, SPS | 2922 | ||||
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This paper concentrates on theoretical studies of Transverse Mode Coupling Instability at the SPS. It shows the expected thresholds based on a HEADTAIL tracking model and on impedance values estimated from previous measurements. First, the effect of space charge is addressed as an important ingredient at the low energies. Subsequently, the change of TMCI threshold possibly induced by a higher injection energy into the SPS (plausible according to the upgrade studies) is investigated and a scaling law with energy is derived.
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THPCH065 | Suppression of Transverse Instability by a Digital Damper | damping, impedance, kicker, antiproton | 2934 | ||||
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When a beam phase space density increases, it makes its motion intrinsically unstable. To suppress the instabilities, dampers are required. With a progress of digital technology, digital dampers are getting to be more and more preferable, compared with analog ones. Conversion of an analog signal into digital one is described by a linear operator with explicit time dependence. Thus, the analog-digital converter (ADC) does not preserve a signal frequency. Instead, a monochromatic input signal is transformed into a mixture of all possible frequencies, combining the input one with multiples of the sampling frequency. Stability analysis has to include a cross-talk between all these combined frequencies. In this paper, we are analyzing a problem of stability for beam transverse microwave oscillations in a presence of digital damper; the impedance and the space charge are taken into account. The developed formalism is applied for antiproton beam in the Recycler Ring at Fermilab.
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THPLS105 | Characterization of the SPARC Photo-injector with the Movable Emittance Meter | emittance, cathode, laser, diagnostics | 3523 | ||||
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As a first stage of the commissioning of SPARC accelerator a complete characterization of the photo-injector is planned. The objective is the optimization of the RF-gun setting that best matches the design working point and, generally, a detailed study of the emittance compensation process providing the optimal value of emittance at the end of the linac. For this purpose a novel beam diagnostic, the emittance-meter, consisting of a movable emittance measurement system, was conceived and built. This paper presents the results of the first measurements with the emittance-meter showing the characteristics and the performance at the SPARC photo-injector.
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