05 Beam Dynamics and Electromagnetic Fields
D06 Code Developments and Simulation Techniques

Paper	Title	Page
MOYCP01	Design and Simulation of IOTA - a Novel Concept of Integrable Optics Test Accelerator	16
	S. Nagaitsev, A. Valishev Fermilab, Batavia, USA V.V. Danilov ORNL, Oak Ridge, Tennessee, USA D.N. Shatilov BINP SB RAS, Novosibirsk, Russia
	The use of nonlinear lattices with large betatron tune spreads can increase instability and space charge thresholds due to improved Landau damping. Unfortunately, the majority of nonlinear accelerator lattices turn out to be nonintegrable, producing chaotic motion and a complex network of stable and unstable resonances. Recent advances in finding the integrable nonlinear accelerator lattices have led to a proposal to construct at Fermilab a test accelerator with strong nonlinear focusing which avoids resonances and chaotic particle motion. This presentation will outline the main challenges, theoretical design solutions and construction status of the Integrable Optics Test Accelerator underway at Fermilab.
	Slides MOYCP01 [2.816 MB]
MOPPC053	Modeling of Bending Magnets for SIRIUS	250
	X.R. Resende, R. Basílio, L. Liu, P.P. Sanchez, G. Tosin LNLS, Campinas, Brazil
	The new Brazilian synchrotron source, Sirius, will be a 3 GeV storage ring with a triple bend lattice with a minimum emittance of 1.7 nm rad. The ring dipoles are excited with permanent magnets. The middle bend has a small 1.4 degree slice in its center with 1.94 T field and serve as an additional hard X-ray source with critical energy of 11.6 keV. Other bending magnets have low 0.50 T field with gradients, allowing for a further emittance reduction. The bending slice shows a longitudinal profile with no uniform field plateau and with long-range fringe fields which are coupled with the fields of neighbouring dipoles. To take into account the interaction of the field-intersecting dipoles, realistic 3D models of the magnets have been created and their field configuration solved using finite element techniques. Field maps calculated from the 3D magnet models were used for the construction of segmented models of bend elements in beam dynamics codes.
MOPPC054	Multi-code Modelling of Momentum Collimation in the TRIUMF ARIEL Linac	253
	F.W. Jones, Y.-C. Chao, C. Gong TRIUMF, Canada's National Laboratory for Particle and Nuclear Physics, Vancouver, Canada
	The electron linac component of the TRIUMF-ARIEL facility will provide CW beams of 50-75 MeV and up to 0.5 MW of beam power, with consequent requirements for low-loss operation. One factor in controlling beam quality is the reduction of the low-momentum tail arising from the rf-modulated 300 KV electron gun and initial capture elements prior to acceleration in the 10 MeV Injector linac. To study momentum collimation in the 10 MeV transfer line to the main linac, and its implications for downstream beam characteristics, a simulation model has been constructed using several tracking and optics codes, linked together by scripts and data converters. The model follows the evolution of the beam from the e-gun through the injector cryo-module and the medium energy transfer line where the proposed collimator is located. The components, methods and results of this application are described in detail.
MOPPC055	A New Platform for Global Optimization	256
	C. Gong, Y.-C. Chao TRIUMF, Canada's National Laboratory for Particle and Nuclear Physics, Vancouver, Canada
	Funding: Funding is received from Natural Sciences and Engineering Research Council of Canada and National Research Council of Canada for this research. This paper describes a new platform for the multi-objective global optimization of accelerator design. While local optimization is relatively simple, global optimization for accelerator design remains a challenging task. The user often must write many lines of code to combine the output of a large variety of simulation engines, then send the results to the optimization engine. The optimization code also requires significant revision when applied to different problems. This paper presents an alternative method. The TRIUMF optimization platform, based on the genetic algorithm, is an extension of the PISA framework. It uses a flexible XML input format, in which users can easily combine multiple physics engines, such as ASTRA and PARMELA, into the same optimization problem. The TRIUMF platform is also parallel capable, designed to take advantage of computation clusters such as WestGrid. Results of the optimization platform applied to TRIUMF's 50 MeV, 0.5 MW electron linac are shown.
MOPPC056	The SolMaxP Code	259
	A. Chancé, N. Chauvin, R.D. Duperrier CEA/DSM/IRFU, France
	In modern sciences, use of high performance computing (HPC) has become a necessity to move forward in the modeling of complex systems. For large-scale instruments like accelerators, HPC permits the virtual prototyping of very onerous parts and, thus, helps to reduce development costs. The SolMaxP code (for Solving Maxwell in Plasma) has been developed to allow complex simulations of multi-species plasma coupled with electromagnetic fields, whether the electromagnetic background is or is not self-consistent with the plasma dynamics. This paper presents the main algorithm of the code and gives several examples of applications.
MOPPC057	Some Comments to Magnetic Field Representation for Beam Dynamic Calculations	262
	P. Schnizer, E.S. Fischer GSI, Darmstadt, Germany A. Mierau TEMF, TU Darmstadt, Darmstadt, Germany B. Schnizer TUG/ITP, Graz, Austria
	Machines with high currents and small apertures, as used for SIS100 of the FAIR project, require a sincere understanding of the resonances excited by the magnetic field distortions; typically performed by tracking codes. These codes model the field errors using a Taylor Series approximation of the field quality at the track of the ideal particle. The path of the particle within the elliptic aperture of the dipole is curved; thus the standard approach of using plane circular multipoles fails to model the real symmetry of the magnetic field, an important feature of effective field description for beam loss calculations. Therefore toroidal elliptic multipoles were developed which allow describing the magnetic field concisely in an elliptic vacuum chamber in curved dipoles and quadrupoles. In this talk we present the appropriate description and its limitation, illustrate their usefullness based on the static and transient magnetic field measurements of the first curved SIS100 dipole next to the SIS18 dipole.
MOPPC058	Eigenmode Computation for Ferrite-loaded Cavity Resonators	265
	K. Klopfer, W. Ackermann, T. Weiland TEMF, TU Darmstadt, Darmstadt, Germany
	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.
MOPPC059	Various Approaches to Electromagnetic Field Simulations for RF Cavities	268
	C. Liu, W. Ackermann, W.F.O. Müller, T. Weiland TEMF, TU Darmstadt, Darmstadt, Germany
	Funding: Work supported by BMBF under contract 05H09RD5. The Superconducting Proton Linac (SPL) cavity is mainly designed and conducted by CERN. It is a part of the planned injector upgrade of the Large Hadron Collider (LHC). The SPL cavity is used to accelerate the ion beam from 160 MeV to 5GeV and served as a driver for neutrino facilities and radioactive beam facilities. In the Superconducting Proton Linac (SPL) cavity, it is very important to calculate the eigenmodes precisely, because many higher-order modes (HOMs) can lead to particle beam instabilities. We used and compared three different ways to calculate the eigenmodes in the SPL cavity: field simulation with hexahedron mesh in frequency domain, field simulation with hexahedron mesh in time domain, and field simulation with tetrahedral mesh and higher order curvilinear elements. In this paper the principles of the three numerical methods will be introduced and compared. Finally the calculated results will be presented.
MOPPC060	Investigations into Beam Life Time in Low Energy Storage Rings	271
	A.I. Papash, A.V. Smirnov MPI-K, Heidelberg, Germany A.I. Papash JINR, Dubna, Moscow Region, Russia C.P. Welsch Cockcroft Institute, Warrington, Cheshire, United Kingdom
	Funding: Work supported by the Helmholtz Association of National Research Centers and GSI under contract VH-NG-328. In low energy storage rings, beam life time critically depends on the residual gas pressure, scattering effects caused by in-ring experiments and the available machine acceptance. A comprehensive simulation study into these effects has been realized with a focus on the TSR storage ring in Heidelberg and the electrostatic rings ELISA, the AD recycler and the ultra-low energy storage ring (USR). This was done by using the computer code BETACOOL in combination with the OPERA-3D and MAD-X programs. In this contribution, the results from these studies are presented and compared to available experimental data. Based on these simulations, criteria for stable ring operation are then presented.
MOPPC062	Eigenmode Computation for Cavities with Perturbed Geometry Based on a Series Expansion of Unperturbed Eigenmodes	277
	K. Brackebusch, U. van Rienen Rostock University, Faculty of Computer Science and Electrical Engineering, Rostock, Germany
	Funding: Work supported by Federal Ministry for Research and Education BMBF under contracts 05H09HR5 and 05K10HRC. The geometry of an accelerator cavity determines its eigenmodes and thereby its performance characteristics. Therefore, accelerating performance and wakefield characteristics may be improved by an intentional modification of the geometry. However, undesired geometry perturbations due to manufacturing tolerances and operational demands can likewise impair it. To analyze the effects of geometry variations on the eigenmodes, parameter studies are to be undertaken. Using common eigenmode solvers it usually is necessary to perform a full eigenmode computation for each variation step, even if the geometry is only slightly altered. Parameter studies for cavity perturbations thus tend to be computationally extensive and inefficient. In this paper, we present the fundamentals of an efficient eigenmode computation method for varying cavity geometries. Knowing a set of initial eigenmodes of an unperturbed geometry, the method allows expanding the eigenmodes of any geometry that is part of the unperturbed one as a series of the initial eigenmodes. Thereby the computation effort may be significantly reduced. The method is demonstrated by means of analytically evaluable cavity geometries.
MOPPC063	Computation of the 2D Transverse Wake Function of an Electron Cloud for Different Parameters	280
	A. Markoviḱ, G. Pöplau, U. van Rienen Rostock University, Faculty of Computer Science and Electrical Engineering, Rostock, Germany
	Funding: Work supported by DFG under contract number RI 814/20-2. A PIC simulation of the interaction of a positive charged bunch with an e-cloud yields the wake kick from the electrons on the tail particles of the bunch. The wake is induced from a certain offset in the transverse position of the head parts of the bunch which perturb the electron distribution. Such a pre-computed wake functions of each offset part of the bunch are forming a matrix which could be used for investigating single bunch stability under several assumptions. In this paper we investigate the linear scalability of the kick with the offset value. Furthermore we investigate the wake values for different realistic electron densities. Another important parameter for realizing the single bunch stability simulation is the optimal number of bunch slices in longitudinal direction. Here we study the thickness of the slices in conjunction with the mobility of the electrons around the beam axis.
MOPPC064	Simulation of the Behavior of Ionized Residual Gas in the Field of Electrodes	283
	G. Pöplau, U. van Rienen Rostock University, Faculty of Computer Science and Electrical Engineering, Rostock, Germany A. Meseck HZB, Berlin, Germany
	Funding: Work supported by BMBF under contract number 05K10HRC Light sources of the next generation such as ERLs require minimal beam losses as well as a stable beam position and emittance over the time. Instabilities caused by ionized residual gas have to be avoided. In this paper we present simulations of the behavior of ionized residual gas in the field of clearing electrodes and investigate e.g. clearing times. For these simulations we apply MOEVE PIC Tracking developed at Rostock University. We demonstrate numerical results with parameters planed for the ERL BERLinPro.
MOPPC066	A Design of Thermionic Electron Gun for Traveling Wave Electron-linac in order to Inject Beam into Booster Synchrotron Accelerator	286
	S. Ahmadian, F. AbbasiDavani, F. Ghasemi, M.Sh. Shafiee sbu, Tehran, Iran
	Applying computational codes functioning on the basis of methods such as Finite Integration caused the designing of different parts of an accelerator to be done faster and with more precision. The first step in using new software is the validation of these codes by experimental results, analytic relations or validating them against other codes whose validity has already been proved. This research aims to design an appropriate structure for thermionic electron gun of traveling wave electron-linac to be used to inject beam into synchrotron accelerators. Firstly, a simple structure of an electron gun used in TWT tube was simulated, and the parameters such as current, perveance, waist beam position, waist beam radius, beam radius entering anode aperture, and also the electric potential variation in the anode-cathode distance and the electric field of anode aperture were compared by experimental results and analytic relations. After verifying the software accuracy, a design for an electron gun with energy and current respectively 200 keV, 18 A and also initial beam radius of 8mm and minimum beam radius of 2.4 mm situated at the distance of 67.44mm from the cathode, was presented.
MOPPC069	Quantitative Simulation of NIRS-930 Cyclotron	292
	V.L. Smirnov, S.B. Vorozhtsov JINR/DLNP, Dubna, Moscow region, Russia A. Goto, S. Hojo, T. Honma, K. Katagiri NIRS, Chiba-shi, Japan
	The results of the computer modelling of the structural elements of the NIRS-930 cyclotron operational at the National Institute of Radiological Sciences (Chiba, Japan) are presented. The integrated approach to modelling of the cyclotron, including calculation of electromagnetic fields of the structural elements and beam dynamics simulations is described. A computer model of the cyclotron was constructed. Electric and magnetic field distributions and mechanical structures were converted to the beam dynamics code for simulations, in which particle losses on the surfaces of the system elements were estimated. The existing data on the axial injection, magnetic, acceleration and extraction systems of the cyclotron and beam parameter measurements are used for calibration of the simulations. New acceleration regimes could be formulated with the help of the constructed computer model of the machine.
MOPPC070	Field Emission Simulation for KEK-ERL 9-Cell Superconducting Cavity	295
	E. Cenni Sokendai, Ibaraki, Japan T. Furuya, H. Sakai, M. Satoh, K. Shinoe, K. Umemori KEK, Ibaraki, Japan M. Sawamura JAEA/ERL, Ibaraki, Japan
	In order to develop the Energy Recovery Linac at KEK, we are studying the performance of L-band superconducting cavities by means of vertical tests. One of the limiting factor for the cavities performance is power losses due to field emitted electrons. With regard to this phenomena, a particle tracking code is used to study electron trajectories and deposited energy on the inner surface of the cavity. Different emitters location were tested within a range of accelerating field and phases in order to reproduce different scenario. The final goal of this study is to locate the sources of the electrons inside the cavity through a deeper understanding of the phenomena. To validate the results from the simulation the outcome data are compared with other particle tracking codes.
MOPPC072	Mathematical Model of Charged Particles Dynamics Optimization in RFQ Accelerators	298
	A.D. Ovsyannikov St. Petersburg State University, St. Petersburg, Russia
	Mathematical model of optimization of transverse motion of charged particles in accelerators is suggested. Linear and nonlinear systems are considered when describing the transverse motion. Interaction of the particles is taken into account. Optimization algorithm based on minimax functionals is built. Numerical results for RFQ accelerators are presented.
MOPPC073	Improvements in the PLACET Tracking Code	301
	A. Latina, E. Adli, D. Schulte, J. Snuverink CERN, Geneva, Switzerland B. Dalena CEA/IRFU, Gif-sur-Yvette, France
	The tracking code PLACET simulates beam transport and orbit corrections in linear accelerators. It incorporates single- and multi-bunch effects, static and dynamic imperfections. It has an interface based on both Tcl/Tk and Octave to provide maximum flexibility and easy programming of complex scenarios. Recently, new functionality has been added to expand its simulation and tuning capabilities, such as: tools to perform beam-based alignment of non-linear optical systems, possibility to track through the interaction region in presence of external magnetic fields (detector solenoid), higher order imperfections in magnets, better tools for integrated feedback loops. Moreover, self contained frameworks have been created to ease the simulation of CLIC Drive Beam, CLIC Main Beam, and other existing electron machines such as CTF3 and FACET.
MOPPC074	Evolution of MAD-X in the Framework of LHC Upgrade Studies	304
	A. Latina, L. Deniau CERN, Geneva, Switzerland
	The design efforts for the High Luminosity upgrade of the Large Hadron Collider (HL-LHC) will require significant extensions of the MAD-X code widely used for designing and simulating particles accelerators. For this purpose, several new capabilities have been added to the code, namely the possibility to simulate crab cavities for crossing angle compensation, with their imperfections; the selective introduction of thick quadrupole elements for particles tracking, improving the previous implementation entirely based on thin-lenses; and the upgrade of the interface to SixTrack used for distributed tracking with, e.g., LHC@home. These changes are framed into a global redesign of the MAD-X architecture meant to consolidate its structure, improve its performances, and increase its flexibility. Such improvements are described in details in the present paper.
MOPPC075	A Generic Data Model for HeadTail: Design and Implementation with Examples	307
	K.S.B. Li, G. Rumolo CERN, Geneva, Switzerland
	HeadTail has been developed in 2002 for the efficient simulation of instabilities and collective effects in large circular accelerators. Since then, the capabilities of the code have been continuously extended and the output data has become increasingly complex and large-scale ranging from the statistical description of single bunches to the statistical description of all slices within bunches up to the dynamics of the full 6D phase space over several thousands of turns. Processing this data in an effective manner and endowing it with a structure that provides a physical concept calls for new and optimised data formats. To meet state-of-the-art standards, the hierarchical data format (HDF5) has been selected as native output data format together with H5Part and XDMF as native data structures. We describe the implementation of the H5Part and the XDMF data structures into HeadTail and show some illustrative examples for data processing.
MOPPC076	New Features of the Parallel TRACY for Nonlinear Beam Dynamics	310
	M.-S. Chiu, H.-P. Chang NSRRC, Hsinchu, Taiwan
	The TRACY code is used to analyze and simulate the nonlinear beam dynamics of the designed lattice. To speed up the lattice design flow, we parallelized the TRACY by MPI and developed a GUI by GTK+ to integrate the functions of TRACY and added a function of nonlinear optimization adapted from OPA, which is used to optimize the nonlinear driving terms by powell algorithm. The GUI is used for parameter input and data visualization. The procedures of nonlinear optimization and beam dynamics analysis are integrated and streamlined. Users do not need to write and compile the code any more. The results will be demonstrated in this report.
MOPPC077	Simulation and Analysis of the Beam Signal in Taiwan Photon Source Booster	313
	C.C. Chiang, H.-P. Chang, P.J. Chou NSRRC, Hsinchu, Taiwan S.-Y. Lee IUCEEM, Bloomington, Indiana, USA
	The TPS (Taiwan Photon Source) booster is a combined function FODO lattice with six super-periods; the total circumference is 496.8 m. To prepare the analysis tools for beam commissioning, we simulate the TPS booster turn-by-turn BPM data with two programs, MAD-X PTC and Tracy-2.6, which are for both DC (constant beam energy) and AC (beam energy in regular ramping) modes. We analyze the simulation data with MIA (Model Independent Analysis) and ICA (Independent Component Analysis), in order to reconstruct beam parameters like beta function, phase advance, dispersion, etc. We include multipole errors, alignment errors, BPM noises or other noises in simulation, and try to design a good strategy for real data analysis.
MOPPC079	Modelling of the EMMA ns-FFAG Ring Using GPT	319
	R.T.P. D'Arcy, S. Jolly UCL, London, United Kingdom J.K. Jones, B.D. Muratori STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom S.B. van der Geer Pulsar Physics, Eindhoven, The Netherlands
	EMMA (Electron Machine with Many Applications) is a prototype non-scaling Fixed-Field Alternating Gradient (ns-FFAG) accelerator whose construction at Daresbury Laboratory, UK, was completed in the autumn of 2010. The energy recovery linac ALICE will serve as an injector for EMMA, within an energy range of 10 to 20 MeV. The injection line consists of a symmetric 30 degree dogleg to extract the beam from ALICE, a matching section and a tomography section for transverse emittance measurements. This is followed by a transport section to the injection point of the EMMA ring. The ring is composed of 42 cells, each containing one focusing and one defocusing quadrupole. Acceleration over many turns of the EMMA machine has recently been confirmed. In some cases the bunch will traverse upwards of 100 turns, at which point the effects of space-charge may be significant. It is therefore necessary to model the electron beam transport in the ring using a code capable of both calculating the effect of and compensating for space-charge. Therefore the General Particle Tracer (GPT) code has been used. A range of injection beam parameters have been modeled for comparison with experimental results.
MOPPC080	Modeling Space Charge in an FFAG with Zgoubi	322
	S.C. Tygier, R. Appleby, H.L. Owen UMAN, Manchester, United Kingdom R.J. Barlow University of Huddersfield, Huddersfield, United Kingdom
	The Zgoubi particle tracker uses a ray tracing algorithm that can accurately track particles with large offset from any reference momentum and trajectory, making it suitable for FFAGs. In high current FFAGs, for example an ADSR driver, space charge has a significant effect on the beam. A transverse space charge model was added to Zgoubi using the interface pyZgoubi. The magnets are sliced and a space charge kick is applied between each slice. Results are presented for an ADSR driver lattice.
MOPPC081	Simulation of RF Cavity Dark Current in Presence of Helical Magnetic Field	325
	G.V. Romanov, V.S. Kashikhin Fermilab, Batavia, USA
	In order to produce muon beam of high enough quality to be used for a Muon Collider, its large phase space must be cooled several orders of magnitude. This task can be accomplished by ionization cooling. Ionization cooling consists of passing a high-emittance muon beam alternately through regions of low-Z material, such as liquid hydrogen, and very high accelerating RF cavities within a multi-Tesla solenoidal focusing channel. But first high power tests of an RF cavity with beryllium windows in a solenoidal magnetic field showed a dramatic drop in accelerating gradient due to RF breakdowns. It has been concluded that external magnetic fields parallel to the RF electric field significantly modifies the performance of RF cavities. However, the magnetic field in a Helical Cooling Channel has a strong dipole component in addition to a solenoidal one. The dipole component essentially changes electron motion in a cavity compared to a pure solenoidal case, making dark current less focused at field emission sites. The simulation of a dark current dynamic in HCC performed with CST Studio Suite is presented in this paper.
MOPPC082	Beam Dynamics Simulations inProject X RFQ with CST Studio Suite	328
	G.V. Romanov Fermilab, Batavia, USA
	Typically the RFQs are designed using the Parmteq, DesRFQ and other similar specialized codes, which produces the files containing the field and geometrical parameters for every cell. The beam dynamic simulations with these analytical fields are, of course, ideal realizations of the designed RFQs. The new advanced computing capabilities made it possible to simulate beam and even dark current in the realistic 3D electromagnetic fields in the RFQs that may reflect cavity tuning, presence of tuners and couplers, RFQ segmentation etc. The paper describes the utilization of full 3D field distribution obtained with CST Studio Suite for beam dynamic simulations using both PIC solver of CST Particle Studio and the beam dynamic code TRACK.
MOPPC083	LinguaFranca - A Graphical User Interface for Accelerator Modeling	331
	T.J. Roberts Muons, Inc, Batavia, USA
	This is a proposed project to develop an innovative Graphical User Interface that permits users to construct, explore, optimize, and evaluate accelerator systems efficiently and effectively. While it will be designed with students in mind, accelerator physicists will also find it useful in dealing with the plethora of modeling tools and their different languages. The internal representation of the system is specifically designed to be useable as a text-based description of the system, and to make it easy for users to interface it to essentially any accelerator-modeling tool, regardless of its description language. Many accelerator designers have expressed frustration with the current “Tower of Babel” among modeling programs, and this project will address that directly. In particular, this will make it straightforward to use fast but less realistic programs to design and optimize a system, and then use slower but more realistic programs to evaluate its performance. Graphical interfaces are emphasized, making it easy to construct the system graphically, display the system and its beam, and use on-screen controls to vary parameters and observe their effects immediately.
MOPPC084	G4beamline Code Development	334
	T.J. Roberts Muons, Inc, Batavia, USA
	Funding: Supported in part by DoE STTR grant DE-FG02-06ER86281. G4beamline is a single-particle-tracking simulation program based on Geant4, optimized specifically for beam lines. It is currently used by several hundred physicists and designers around the world, who apply it to a diverse set of interesting problems. As it includes particle decays and interactions, it is applicable to beams for which decays and interactions are important, such as modern muon facilities that involve ionization cooling. Its description language has been designed to be both versatile and user-friendly, and the program includes high-quality visualization and histogramming capabilities. This paper discusses recent code development and new features, and some interesting applications of the program. G4beamline is an open-source program freely available at http://g4beamline.muonsinc.com
MOPPC085	An Integrated Green Function Poisson Solver for Rectangular Waveguides	337
	R.D. Ryne LBNL, Berkeley, California, USA
	Funding: DOE Office of Science, Office of High Energy Physics and Office of Advanced Scientific Computing Research A new method is presented for solving Poisson's equation inside a rectangular waveguide. The method uses Fast Fourier Transforms (FFTs) to perform mixed convolutions and correlations of the charge density with an integrated Green function. Due to its similarity to the widely used Hockney algorithm for solving Poisson's equation in free space, this capability can be easily implemented in many existing particle-in-cell beam dynamics codes.
MOPPC086	Accelerator Simulation - Beyond High Performance Computing	340
	S. James, G.M. Jung, B.C. Li, K. Muriki, H. Nishimura, Y. Qin, K. Song, C. Sun LBNL, Berkeley, California, USA
	Funding: Work supported by the U.S. Department of Energy under Contract No. DE-AC02-05CH11231. Accelerator modeling and simulation studies heavily rely on High Performance Computing (HPC). Public Cloud computing has opened a new service horizon for HPC by offering an on-demand, Virtual Private Cloud (VPC). Previously, we investigated using Amazon HPC public Cloud for lattice optimization applications and evaluated performance*. In this research, we use the Amazon VPC technology to extend local HPC resources to provide a seamless, hybrid, and secure environment when the demand for computing capacity spikes. * C. Sun et al., "HPC Cloud Applied to Lattice Optimization," Proc. PAC2011, New York, WEP151, p. 1767 (2011).
MOPPC089	CUDA Kernel Design for GPU-based Beam Dynamics Simulations	343
	I.V. Pogorelov, K.M. Amyx, J. Balasalle, J. James Tech-X, Boulder, Colorado, USA M. Borland, R. Soliday, Y. Wang ANL, Argonne, USA
	Funding: Work supported by the US DOE Office of Science, Office of Basic Energy Sciences under grant number DE-SC0004585. Efficient implementation of general-purpose particle tracking on GPUs can result in significant performance benefits to large-scale particle tracking and tracking-based accelerator optimization simulations. We present our work on CUDA kernels for transfer maps of single-particle-dynamics and collective-effects beamline elements, to be incorporated into a GPU-accelerated version of the ANL's accelerator code ELEGANT. In particular, we discuss techniques for efficient utilization of the device shared, cache, and local memory in the design of single-particle and collective-effects kernels. We also discuss the use of data-parallel and hardware-assisted approaches (segmented scan and atomic updates) for resolving memory contention issues at the charge deposition stage of algorithms for modeling collective effects. We present and discuss performance results for the CUDA kernels developed and optimized as part of this project.
MOPPC091	Parallel 3D Simulations to Support Commissioning of a Solenoid-based LEBT Test Stand	349
	B.T. Schwartz, D.T. Abell, D.L. Bruhwiler, Y. Choi, S. Mahalingam, P. Stoltz, J. von Stecher Tech-X, Boulder, Colorado, USA B. Han, M.P. Stockli ORNL, Oak Ridge, Tennessee, USA
	Funding: This work is supported by the US DOE Office of Science, Office of Basic Energy Sciences, including grant No. DE-SC0000844. A solenoid-based low-energy beam transport (LEBT) test stand is under development for the Spallation Neutron Source (SNS). To support commissioning of the test stand, the parallel Vorpal framework is being used for 3D electrostatic particle-in-cell (PIC) simulations of H− beam dynamics in the LEBT, including impact ionization physics and MHz chopping of the partially-neutralized \Hm beam. Here we describe the process of creating a partially-neutralized beam and examine the effects of a single chopping event on the beam's emittance.
MOPPC093	Optimal Fast Multipole Method Data Structures	352
	S. Abeyratne, B. Erdelyi Northern Illinois University, DeKalb, Illinois, USA S.L. Manikonda ANL, Argonne, USA
	The Fast Multipole Method (FMM) has been identified as one of the ten most significant numerical algorithms discovered in the 20th century. The FMM guarantees finding fast solutions to many problems in science, such as calculating Coulomb potentials among large number of particles by reducing memory footprint and run time while attaining very high accuracy levels. One important practical issue that we have to solve in implementing a FMM algorithm is organizing large amounts of data, also called data structuring. The non-adaptive FMM is appropriate when the particles are uniformly distributed while the adaptive FMM is most efficient when the distribution is non-uniform. In practice, we typically encounter highly non-uniform 3D particle distributions. This paper summarizes our implementation of a 3D adaptive FMM algorithm data structure setup for non-uniform particle distributions.
MOPPC094	Charge Density Estimations with Orthogonal Polynomials	355
	D. Hernandez, B. Erdelyi Northern Illinois University, DeKalb, Illinois, USA
	Funding: This work was supported by the Department of Energy under Contract No. DE-FG02-08ER41532 with Northern Illinois University. A beam’s charge density, treated as a smooth and continuous function can be approximated using orthogonal series, allowing a solution of Poisson’s equation to be found. Getting the most accurate solution to the electric potential requires the best approximated charge density. Several beam distributions are approximated using Jacobi polynomials generated by the recursion relation and the moment method. Varying both the particle number and order of the approximation gives a chance to not only compare the performance of the different polynomials, but allows to determine if a particular combination of order and particle number works better for a particular function. Although all three orthogonal polynomials used give similar results, the approximation coefficients should be allowed to converge and taken to high orders for best results. This is clearly seen on the single Gaussian approximation, where after five million particles, the difference between the distributions remains constant and the highest tested order gives best results.
MOPPC095	XAL's Online Model at ReA3 to Understand Beam Performance	358
	C. Benatti NSCL, East Lansing, Michigan, USA P. Chu, M.J. Syphers, X. Wu FRIB, East Lansing, Michigan, USA
	Funding: This material is based on work supported by the National Science Foundation under Grant No. PHY-1102511 and by Michigan State University. The ReA3 facility at the NSCL at MSU has been designed to reaccelerate rare isotope beams to 3MeV/u. ReA3 consists of a charge to mass selection section, a normal conducting RFQ, a superconducting linac, and transport beam lines that deliver the beam to the experiments. The beam optics designs were developed using COSY and IMPACT. A code with an online model capable of interacting with the control system, such as XAL, developed at SNS, would be ideal for studying this system*. New elements have been added to XAL’s already extensive list of supported devices in order to model elements unique to the NSCL. The benchmarking process has been completed for establishing the use of XAL’s Online Model at the NSCL, and preliminary results from its use at the ReA3 control room have been obtained. The development of applications to fit the needs of the program is ongoing. A summary of the benchmarking process is presented including both transverse and longitudinal studies. * J. Galambos et al., Proc. PAC 2005, p. 79, (2005); doi: 10.1109/PAC.2005.1590365.
MOPPC096	Multiphysics Applications of ACE3P	361
	K.H. Lee, C. Ko, Z. Li, C.-K. Ng, L. Xiao SLAC, Menlo Park, California, USA G. Cheng, H. Wang JLAB, Newport News, Virginia, USA
	Funding: Work supported by US DOE Offices of HEP, ASCR and BES under contract AC02-76SF00515. The TEM3P module of ACE3P, a parallel finite-element electromagnetic code suite from SLAC, focuses on the multiphysics simulation capabilities, including thermal and mechanical analysis for accelerator applications. In this pa- per, thermal analysis of coupler feedthroughs to supercon- ducting rf (SRF) cavities will be presented. For the realistic simulation, internal boundary condition is implemented to capture RF heating effects on the surface shared by a di- electric and a conductor. The multiphysics simulation with TEM3P matched the measurement within 0.4%.
MOPPD004	oPAC - Optimizing Accelerators through International Collaboration	373
	C.P. Welsch Cockcroft Institute, Warrington, Cheshire, United Kingdom C.P. Welsch The University of Liverpool, Liverpool, United Kingdom
	Funding: Work supported by the European Union under contract PITN-GA-2011-289485. The optimization of the performance of any particle accelerator critically depends on an in-depth understanding of the beam dynamics in the machine and the availability of simulation tools to study and continuously improve all accelerator components. It also requires a complete set of beam diagnostics methods to monitor all important machine and beam parameters with high precision and a powerful control and data acquisition system. Within the oPAC project all these aspects will be closely linked with the aim to optimize the performance of present and future accelerators that lie at the heart of many research infrastructures. The project brings together 22 institutions from around the world. With a project budget of 6 M€, it is one of the largest research and training networks ever funded by the EC. This contribution gives an overview of the network's broad research program and summarizes the training events that will be organized by the consortium within the next 4 years.
MOPPD061	LHC@home: a Volunteer Computing System for Massive Numerical Simulations of Beam Dynamics and High Energy Physics Events	505
	M. Giovannozzi, F. Grey, A. Harutyunyan, N. Hoimyr, P.L. Jones, A. Karneyeu, M.A. Marquina, E. McIntosh, B. Segal, P. Skands CERN, Geneva, Switzerland D. Lombraña González CCC, 1211Geneva 23, Switzerland L. Rivkin, I. Zacharov EPFL, Lausanne, Switzerland
	Recently, the LHC@home system has been revived at CERN. It is a volunteer computing system based on BOINC which allows boosting the available CPU-power in institutional computer centers by the help of individuals that donate the CPU-time of their PCs. Currently two projects are hosted on the system, namely SixTrack and Test4Theory. The first is aimed at performing beam dynamics simulations, while the latter deals with the simulation of high-energy events. In this paper the details of the global system, as well a discussion of the capabilities of either project will be presented. Milestones of progress of the projects will also be discussed.
TUOAA01	3-Dimensional Modeling of Electron Clouds in Non-uniform Magnetic Fields	1059
	S.A. Veitzer, P. Stoltz Tech-X, Boulder, Colorado, USA J.A. Crittenden, K.G. Sonnad CLASSE, Ithaca, New York, USA
	Funding: This work was performed under the auspices of the Department of Energy as part of the ComPASS SCiDAC-2 project (DE-FC02-07ER41499) and by the National Science Foundation Grant PHY-0734867. Electron clouds have the potential to pose serious limitations on accelerator performance in both hadron and lepton beams. Experiments using rf diagnostics are being performed to measure electron cloud densities at a number of accelerator facilities. However, it is difficult to calibrate plasma density with signal strength in these experiments, and modeling involves a number of technical and numerical challenges. Typically 2-Dimensional electrostatic methods have been used to model cloud buildup under beam crossing conditions. However, since traveling-wave rf experiments typically occur over many meters of beam pipe where magnetic fields are changing, one needs to develop 3-Dimensional electromagnetic models in order to accurately simulate rf diagnostics. We have developed accurate models of electron cloud-induced phase shifts in rf in a system with spatially varying magnetic field configurations using the plasma simulation code VORPAL. We present here results for measuring phase shifts in the CESR wiggler with realistic, spatially non-uniform magnetic field configurations.
	Slides TUOAA01 [18.367 MB]
TUEPPB007	A Self Consistent Multiprocessor Space Charge Algorithm that is Almost Embarrassingly Parallel	1128
	E.W. Nissen JLAB, Newport News, Virginia, USA B. Erdelyi Northern Illinois University, DeKalb, Illinois, USA S.L. Manikonda ANL, Argonne, USA
	Funding: Notice: Authored by Jefferson Science Associates, LLC under U.S. DOE Contract No. DE-AC05-06OR23177. We present a space charge code that is self consistent, massively parallelizeable, and requires very little communication between the computer nodes; making the calculation almost embarrassingly parallel. This method is implemented in the code COSY Infinity where the differential algebras used in this code are important to the algorithm's proper functioning. The method works by calculating the self consistent charge distribution using the statistical moments of the test particles, and converting them into polynomial series coefficients. These coefficients are combined with differential algebraic integrals to form the potential, and electric fields. The result is a transfer map which contains the effects of space charge. This method allows for massive parallelization since its statistics based solver doesn’t require any binning of the particles, and only requires a vector containing the partial sums of the statistical moments for the different nodes to be passed. All other calculations are done independently. The resulting maps can be used to analyze the system using normal form analysis, as well as advance particles in numbers and at speeds that were previously impossible.
FRXAB01	Symplectic Tracking and Compensation of Dynamic Field Integrals in Complex Undulator Structures	4165
	J. Bahrdt, G. Wüstefeld HZB, Berlin, Germany
	This presentation covers analytical models that describe the interaction of an electron beam with the magnetic field of undulators. Analytic approximations to the Hamilton-Jacobi equation yield generating functions useful for particle tracking and therefore efficient simulation. Analytic expressions for kick maps of APPLE II undulators are presented as well. Passive and active shimming schemes including magic fingers and current sheets are also modeled. Applications at BESSY II are discussed which ensure efficient injection during top-up to satisfy machine protection and radiation safety requirements.
	Slides FRXAB01 [1.922 MB]