IPAC2014 - Classification: 05 Beam Dynamics and Electromagnetic Fields / D06 Code Developments and Simulation Techniques

Paper	Title	Page
MOPRO007	GPU-Accelerated Long-Term Simulations of Beam-Beam Effects in Colliders	77
	B. Terzić, F. Lin, V.S. Morozov, Y. Roblin, H. Zhang JLab, Newport News, Virginia, USA M. Aturban, D. Ranjan, M. Zubair ODU CS, Norfolk, Virginia, USA
	Funding: Authored by Jefferson Science Associates, LLC under U.S. DOE Contract No. DE-AC05-06OR23177. We present an update on the development of the new code for long-term simulation of beam-beam effects in particle colliders. The underlying physical model relies on a matrix-based arbitrary-order particle tracking (including a symplectic option) for beam transport and the generalized Bassetti-Erskine approximation for beam-beam interaction. The computations are accelerated through a parallel implementation on a hybrid GPU/CPU platform. With the new code, previously computationally prohibitive long-term simulations become tractable. The new code will be used to model the proposed Medium-energy Electron-Ion Collider (MEIC) at Jefferson Lab.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPRO007
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MOPRO067	Analytic Calculation of Electric Fields of Coherent THz Pulses	234
	M. Schwarz, P. Basler, M. Guenther, A.-S. Müller, M. von Borstel KIT, Karlsruhe, Germany M.T. Schmelling MPI-K, Heidelberg, Germany
	The coherently emitted electric field pulse of a short electron bunch is obtained by summing the fields of the individual electrons, taking phase differences due to different longitudinal positions into account. For an electron density, this sum becomes an integral over the charge density and frequency spectrum of the emitted radiation, which, however, is difficult to evaluate numerically. In this paper, we present a fast analytic method valid for arbitrary bunch shapes. We also include shielding effects of the beam pipe and consider ultra-short bunches, where the high frequency part of the coherent synchrotron spectrum is cut-off not by the inverse bunch length but by the critical frequency of synchrotron radiation. Our technique is applied to bunches, simulated simulated for the linac-based FLUTE accelerator test facility at KIT.
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MOPRO095	Application Program for Automatically Getting the First Turn and Closed Orbit in TPS Commissioning	310
	M.-S. Chiu, H.-P. Chang, P.J. Chou, F.H. Tseng NSRRC, Hsinchu, Taiwan
	Taiwan Photon Source (TPS) is a 3 GeV third generation electron synchrotron light source, consist of 5 major modules: LINAC, LTB transfer line, booster ring, BTS transfer line and storage ring. Its beam commissioning is scheduled in 2014. Getting the first turn and approaching the closed orbit is a crucial step for achieving stored beam in ring-based accelerator commissioning. In order to make first turn beam commissioning efficient, we develop a MATLAB-based application program based on AT and MML for automatic beam steering and closed orbit search. The algorithm and simulation results are presented.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPRO095
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MOPME002	Simulation of the Thermal Deformation and the Cooling of a Four-rod Radio Frequency Quadrupole	376
	B. Masschaele, H. De Gersem, T. Roggen KU Leuven, Kortrijk, Belgium H. Podlech IAP, Frankfurt am Main, Germany D. Vandeplassche SCK•CEN, Mol, Belgium
	Funding: This work is supported by the European Atomic Energy Community’s Seventh Framework Programme under grant agreement nr. 269565 (MAX project). A four-rod radio frequency quadrupole (RFQ) contains four modulated rods kept in place by a number of stems and fixed within a resonating cavity. The position and the modulation of the rods determines the focusing and accelerating properties of the RFQ. The resonating field induces currents, and by that Joule losses, in the stems, rods and tuning plates. The temperature increase causes a mechanical deformation which may lead to a deteriorated performance of the RFQ. The temperature increase is kept small by cooling the rods and stems. A new layout of cooling channels has been proposed. The paper reports about coupled electromagnetic, fluid-dynamic, thermal and structural dynamic field simulations carried out for predicting the mechanical deformation of the stems and the rods. The results for the four-rod RFQ planned for the MYRRHA proton accelerator indicate a change of 47 μm of the distance between the rods when cooling water with a velocity of 3 m/s is applied.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPME002
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MOPME003	Radio Frequency Quadrupole Surrogate Field Models Based on 3D Electromagnetic Field Simulation Results	379
	T. Roggen, H. De Gersem, B. Masschaele KU Leuven, Kortrijk, Belgium W. Ackermann, S. Franke, T. Weiland TEMF, TU Darmstadt, Darmstadt, Germany
	Funding: This research is funded by grant ”KUL 3E100118” ”Electromagnetic Field Simulation for Future Particle Accelerators”, Project FP7-Euratom No. 269565 and the Belgian Nuclear Research Centre (SCK•CEN) Surrogate field models for the different sections of a Radio Frequency Quadrupole (RFQ) are developed, identified on the basis of finite element (FE) simulation and embedded in a moment method beam dynamics simulation code. The models are validated for both theoretical and realistic RFQ designs.
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MOPME004	RFQ Solver based on the Method of Moments	382
	C. Raucy, C.V.G. Craeye UCL, Louvain-la-Neuve, Belgium D. Vandeplassche SCK•CEN, Mol, Belgium
	Funding: SCK•CEN The aim of this research is to improve the accuracy and the simulation time of solvers devoted to Radio Frequency Quadrupoles (RFQ). The Method of Moments is a full-wave method used to solve scattering problems. Its main advantage over FE or FDTD solvers is that unknowns are limited to the boundaries of the object. The resulting dense system of equations can be solved very rapidly with the help of domain-decomposition approaches (e.g. Macro Basis Functions), especially when the level of detail is very fine compared to the wavelength, which is definitely the case for RFQ’s. Such a method however needs a first regularization method to overcome the low-frequency breakdown in order to compute the Macro Basis Functions. The respective field contributions of different parts of the global structure (e.g. rods vs. stems) can also easily be finely investigated. Numerical results will be presented based on the Myrrha RFQ. The low-frequency breakdown issue due to the very fine mesh will be discussed and a solution based on the so-called Loop-Tree* decomposition will be detailed. * Ozdemir, N.A.; Gonzalez-Ovejero, D.; Craeye, C., IEEE Tr.AP, vol.61, no.4, pp.2088, 2098, April 2013 ** Andriulli, F.P., IEEE Tr.AP, vol.60, no.5, pp.2347, 2356, May 2012
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MOPME005	Simulation of the Extraction and Transport of a Beam from the SILHI Source with the Warp Code	385
	A. Chancé, N. Chauvin CEA/DSM/IRFU, France
	In a low energy beam transfer (LEBT) line, space charge effects are dominant and make the motion of the particles strongly non-linear. So, the beam dynamics is directly dependent on the 6D distribution of the particles after the ion source extraction system. It is thus essential to simulate accurately the source extraction region and the space charge compensation after it to try to reach an agreement between the simulations and the measurements. Generally, the ion source extraction system is simulated with electrostatic codes (often using simple model for space charge) from which the 6D beam distribution is derived. Then, this distribution can be used as an initial condition to simulate the beam transport in the LEBT with a time dependent PIC code that takes into account space charge compensation. We propose here to simulate accurately the SILHI source extraction system with the Warp and AXCEL-INP codes. The SILHI ion source will be quickly presented and some simulations results will be given and discussed.
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MOPME007	Multi-objective Optimization of the Linear and Non-linear Beam Dynamics of Synchrotron SOLEIL	388
	X.N. Gavaldà, A. Díaz Ortiz, L.S. Nadolski SOLEIL, Gif-sur-Yvette, France
	One of the most important challenges for the actual and new third generation of synchrotron light sources is to optimize the linear and the non-linear beam dynamics of these strong focusing lattices. The optimization of a storage ring lattice is a multi-objective problem that involves a high number of constraints in a multi-dimensional parameter space. In this paper we used Multi-Objective Genetic Algorithm (MOGA) and the tracking code ELEGANT to optimize the linear and non-linear beam dynamics of the SOLEIL synchrotron light source. The objectives of our optimization are the dynamical aperture and the momentum aperture which are strongly correlated to the injection efficiency and the Touschek lifetime, respectively. This paper will discuss the deployment of this computational approach using the SOLEIL computer cluster. The first results will also be presented and we will discuss possible improvements.
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MOPME008	3d Full Electromagnetic Beam Dynamics Simulations of the Pitz Photoinjector	391
	Y. Chen, E. Gjonaj, W.F.O. Müller, T. Weiland TEMF, TU Darmstadt, Darmstadt, Germany
	Funding: work supported by DESY, Hamburg and Zeuthen sites The electromagnetic (EM) simulation software CST STUDIO SUITE® * has been applied to investigate the beam dynamics for the electron gun of the Photo Injector Test facility at DESY, Zeuthen site (PITZ). A series of 3D beam dynamics simulations are performed to study the bunch injection process at PITZ with the objective of clarifying the discrepancies between measurements and simulations. Multiple comparisons are presented for the transverse emittance and the total emitted charge between the measurement data and simulation results using CST STUDIO SUITE®and Astra *. Computer Simulation Technology AG, website: http://www.cst.com/ ** K. Floettmann A Space Charge Tracking Algorithm, user manual (version 3), 2011
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPME008
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MOPME009	Numerical Calculation of Electromagnetic Fields in Acceleration Cavities under Precise Consideration of Coupler Structures	394
	C. Liu, W.A. Ackermann2, W.F.O. Müller, T. Weiland TEMF, TU Darmstadt, Darmstadt, Germany
	Funding: Work supported by BMBF under contract 05H12RD5 During the design phase of superconducting radio frequency (RF) accelerating cavities a challenging and difficult task is to determine the electromagnetic field distribution inside the structure with the help of proper computer simulations. Although dissipation due to lossy materials is neglected in the current work, in reality, because energy transfer appears due to the design of the superconducting cavities, the numerical eigenmode analysis based on real-valued variables is no longer suitable to describe the dissipative acceleration structure. Dissipation can appear with the help of dedicated higher order mode (HOM) couplers, the power coupler as well as the beam tube once the resonance frequency is above the cutoff frequency of the corresponding waveguide. At the Computational Electromagnetics Laboratory (TEMF) a robust parallel eigenmode solver based on complex-valued finite element analysis is available. The eigenmode solver has been applied to the TESLA 1.3 GHz and the third harmonic 3.9 GHz nine-cell cavities to determine the resonance frequency, the quality factor and the corresponding field distribution of eigenmodes.
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MOPME010	A MAD-X Model of the HIT Accelerator	397
	R. Cee, M. Galonska, T. Gläßle, Th. Haberer, K. Höppner, A. Peters, S. Scheloske HIT, Heidelberg, Germany
	For a medical accelerator facility like the Heidelberg Ion-Beam Therapy Centre (HIT) an online simulation tool with read and write access to the control system and the database is essential for effective beam alignment and beam spot size adjustment at the patient position. Since the commissioning of HIT the simulation programme Mirko from GSI Darmstadt has been in use for the simulation of the beamlines and the synchrotron. While Mirko fully complies with the demands and is still in regular use, the long-term support of the HIT-Mirko derivate cannot be guaranteed. We have therefore started to set up a new simulation environment based on the MAD-X programme from CERN. In a first step we built a MAD-X model of the HIT accelerator using the MAD-X export function of Mirko. The resulting sequences were transformed and extended into executable MAD-X files. The simulation results were validated against Mirko and a good agreement of the calculated beam envelopes could be achieved. Works on the graphical user interface (GUI) for visualisation of and interaction with the beam envelopes and the link to the control system are in progress.
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MOPME011	Matrix Integration of ODEs for Spin-orbit Dynamics Simulation	400
SUSPSNE063	use link to see paper's listing under its alternate paper code
	A.N. Ivanov, Y. Senichev FZJ, Jülich, Germany
	MODE (Matrix integration of Ordinary Differential Equations) is a software package that provides nonlinear matrix maps building for spin-orbit beam dynamics simulation. In this article we briefly describe the developed integrated development environment features and present computational comparison with other simulation tools. MODE mathematical model is based on Newton-Lorentz and T-BMT equations that are expanded to Taylor series up to the necessary order of nonlinearity. The numerical algorithm is based on matrix presentation of Lie propagator. Spin-orbit simulation results of MODE are compared with results of COSY Infinity and OptiM. MODE provides a flexible graphic user interface, code auto complete technology and visual designer for accelerators. There is also a possibility to generate codes in different programming languages and parallelization techniques.
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MOPME012	A New Tool for Automated Orbit and Spin Motion Analysis	403
SUSPSNE066	use link to see paper's listing under its alternate paper code
	D. Zyuzin FZJ, Jülich, Germany
	There are a lot of tools to simulate beam dynamics in accelerators of various types. Many of them are intended to use for specific purposes, and there are universal codes that can simulate both orbit and spin motion in magnetic and electrostatic structures. To start using these codes beam physicist first should have learn syntax, know features and methods how to describe lattice and beams in this particular code. Output data structures of different simulation programs are also vary and depend on peculiarities of each program. This paper proposes a new tool for automated generation and execution of input files for simulation programs and for data analysis of output data. The developed tool allows to describe a lattice, calculate different lattice parameters (like tunes) using simulation program, track particles inside the lattice and analyze various parameters of output data (like beam depolarization). Simulations and analysis can be done in parallel using built-in parallelization mechanisms, and all results can be stored in the database and can be easily fetched when needed. The tool is used to simulate beam and spin dynamics in different lattices to increase spin coherence time.
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MOPME013	A Python Poisson Solver for 3D Space Charge Computations in Structures with Arbitrary Shaped Boundaries	406
	G. Pöplau, C. Potratz COMPAEC e.G., Rostock, Germany
	Numerical techniques in the field of particle accelerators are mainly driven by the design of next-generation accelerators: The need for higher simulation complexity and the necessity for more and more specialized algorithms arises from the ever increasing need to include a broader range of physical effects and geometrical details in a computer simulation. This, on the other hand requires fast and reliable simulation tools for a limited user base. Therefore, new approaches in simulation software development are necessary to provide useful tools that are well-suited for the task at hand and that can be easily maintained and adapted by a small user community. We show how Python can be used to solve numerical problems arising from particle accelerator design efficiently. As model problem, the computation of space charge effects of a bunch in RFQs including the vane geometry was chosen and a suited solver was implemented in Python.
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MOPME014	Automated Mode Recognition Algorithm for Accelerating Cavities	409
	K. Brackebusch, T. Galek, 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 contract 05K13HR1. Eigenmode simulations of accelerating structures often involve a large number of computed modes that need to be catalogued and compared. In order to effectively process all the information gathered from eigenmode simulations a new algorithm was developed to automatically recognize modes’ field patterns. In this paper we present the principles of the algorithm and investigate its applicability by means of different single and multi cell cavities. The highest achievable order of correctly recognized modes is of particular interest.
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MOPME017	Study of Higher Order Modes in Multi-Cell Cavities for BESSY-VSR Upgrade	412
	T. Galek, K. Brackebusch, Sh. Gorgi Zadeh, 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 contract 05K13HR1. BESSY-VSR is a planned scheme to upgrade the existing BESSY II storage ring to support variable electron pulse lengths. In addition to the present 0.5 GHz energy replenishment cavity, two additional SRF bunch compressing cavities operating at 1.5 GHz (3rd harmonic) and 1.75 GHz (sub-harmonic), will be installed. These cavities are essential to produce short 1.5 ps bunches with current of up to 0.8 mA per bunch. In order to achieve such high beam currents, higher order modes must be damped in the superconducting cavities. In this work we present analysis of higher order modes in cavities with different mid-cell shapes.
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MOPME018	Quantification of Geometric Uncertainties in Single Cell Cavities for BESSY VSR using Polynomial Chaos	415
SUSPSNE062	use link to see paper's listing under its alternate paper code
	J. Heller, T. Flisgen, C. Schmidt, U. van Rienen Rostock University, Faculty of Computer Science and Electrical Engineering, Rostock, Germany
	Funding: Federal Ministry for Research and Education Germany under contract 05K13HR1 The electromagnetic properties of SRF cavities are mostly determined by their shape. Due to fabrication tolerances, tuning and limited resolution of measurement systems, the exact shape remains uncertain. In order to make assessments for the real life behaviour it is important to quantify how these geometrical uncertainties propagate through the mathematical system and influence certain electromagnetic properties, like the resonant frequencies of the structure's eigenmodes. This can be done by using non-intrusive straightforward methods like Monte-Carlo (MC) simulations. However, such simulations require a large number of deterministic problem solutions to obtain a sufficient accuracy. In order to avoid this scaling behaviour, the so-called polynomial chaos (PC) expansion is used. This technique allows for the relatively fast computation of uncertainty propagation for few uncertain parameters in the case of computationally expensive deterministic models. In this paper we use the PC expansion to quantify the propagation of uncertain geometry on the example of single cell cavities used for BESSY VSR as well as to compare the obtained results with the MC simulation.
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MOPME019	Study of a Fast Convolution Method for Solving the Space Charge Fields of Charged Particle Bunches	418
	D. Zheng, A. Markoviḱ, G. Pöplau, U. van Rienen Rostock University, Faculty of Computer Science and Electrical Engineering, Rostock, Germany
	The kernel of beam dynamics simulations using the particle-in-cell (PIC) model is the solution of Poisson's equation for the electric potential. A very common way to solve Poisson's equation is to use the convolution of charge density and Green's function, the so-called Green's function method. Additionally, the integrated Green's function method* is being used in order to achieve a higher accuracy. For both methods, the convolutions are done using fast Fourier transform based on the convolution theorem. However, the construction of the integrated Green's function and the further convolution is still very time-consuming. The computation can be accelerated without loosing precision if the calculation of Green’s function values is limited to that part of the computational domain with non-zero grid charge density. In this paper we present a general numerical study of these Green's function methods for computing the potential of different bunches: The results can also be used in other simulation codes to improve efficiency. * J. Qiang, S. Lidia, R. D. Ryne, and C. Limborg-Deprey, “A Three-Dimensional Quasi-Static Model for High Brightness Beam Dynamics simulation,” Phys. Rev. ST Accel. Beams, vol 9, 044204 (2006).
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MOPME021	Vicky: Computer Code Update	421
	F. Iazzourene Elettra-Sincrotrone Trieste S.C.p.A., Basovizza, Italy
	Vicky is a computer code for designing and simulating charged particle accelerators. We recall mainly that Vicky is a very user friendly code, the particle motion is described by 10 parameters: four beta-functions, four alpha-functions and two phase advances, and a large variety of insertion devices, wigglers and undulators, linearly and elliptically polarized, are treated. The features include Twiss functions matching, orbit correction, tune and chromaticity adjustment, dynamic aperture and phase space tracking. The paper describes new aspects and the present status. F. IAZZOURENE, “Vicky: A Computer Code for Use in the Design and Simulation of Particle Accelerators”, proceedings IPAC 2011.
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MOPME022	Investigation of the Breakdown and RF Sheath Potential for EAST ICRF Antenna	424
	H. Yang, S. Dong, L. Shang, K. Tang, C.-F. Wu USTC/NSRL, Hefei, Anhui, People's Republic of China
	A new ion cyclotron range of frequency (ICRF) antenna was designed with four current straps in Experimental Advanced Superconducting Tokamak (EAST). It is to provide heating, current drive and some physics experiments in EAST. The breakdown and RF sheath potential for the antenna are investigated by a three dimension electromagnetic code in the paper. The plasma is simulated by a slab with high relative permittivity approximating the plasma loading of the antenna. Calculations show that the maximum of electric field is around the end of the coaxial feeds and the strip line and the electric field is strongly dependent on antenna phasing. Especially the maximum of electric field is decreased to 27.5 KV/cm with the (0,π,π,0) phasing between toroidal straps while the value is 32.8 KV/cm with (0,0,π,π) phasing. A challenge in ICRF is the impurity contamination which is related to sheath potential. The topology of the radio frequency (RF) sheath is optimized to reduce the potential for EAST ICRF antenna. The RF potential is mitigated obviously with the broader side limiter by a factor of 2.
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MOPME023	A High Precision Particle-moving Algorithm for Particle-in-cell Simulation of Plasma	427
SUSPSNE064	use link to see paper's listing under its alternate paper code
	X.F. Li, D.Z. Chen, D. Li, H.K. Yue HUST, Wuhan, People's Republic of China
	A new particle-moving algorithm for particle-in-cell simulation of plasma is developed based on the Linear Multistep Method. The conventional and the new algorithms are investigated by numerical experiments, which are conducted in three typical fashions of the electron motions in electromagnetic fields, that is, cyclotron in homogeneous magnetic field, drift in field and motions in inhomogeneous magnetic field. The new algorithm not only improves the accuracy but also relaxes the time step condition for the simulation. It can increase the computation efficiency.
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MOPME025	New Possibilities of MultP-M Code	433
	M. Gusarova, S. Khudyakov, I.I. Petrushina, Ya.V. Shashkov MEPhI, Moscow, Russia
	Implementation and Testing of the new module package for geometry import of the MultP-M 3D code for multipacting prediction was performed. The results of simulations for the coaxial line specimen using this new module are presented. These results are compared with analytical calculations and experimental data.
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MOPME026	IBS Simulations with Compute Unified Device Architecture (CUDA) Technology	436
	S.A. Glukhov, E.B. Levichev, S.A. Nikitin, P.A. Piminov, D.N. Shatilov, S.V. Sinyatkin BINP SB RAS, Novosibirsk, Russia
	A program code for 6D tracking has been developed taking into account IBS (Intra-Beam Scattering) and Touschek effect and using Monte-Carlo method. The simulation algorithm has been developed on the basis of well-known IBS theory presented in (). The resulting program can be executed using GPGPU devices (General-Purpose Graphics Processing Units) supporting CUDA technology (Compute Unified Device Architecture). J. Le Duff, Single and multiple Touschek effects // Published in In Rhodos 1993, Advanced accelerator physics, vol. 2 573-586. CERN Geneva - CERN-95-06 (95/11,rec. Mar.96) 1993. p. 573-586.
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MOPME027	Parallel Three-dimensional PIC Code for Beam-beam Simulation in Linear Colliders	439
	M.A. Boronina, V.D. Korneev, V.A. Vshivkov ICM&MG SB RAS, Novosibirsk, Russia
	We present our parallel 3D3V particle-in-cell code for the numerical simulations of ultrarelativistic charged beams in supercolliders. In the algorithm we employ the three-dimensional set of Maxwell equations and the Vlasov-Liouville equation for the distribution function of beam particles in 6-dimensional phase space. The code allows performing numerical experiments with an arbitrary density distribution, beam crossing angle and relative offset. From the mathematical point of view the main problem of the three-dimensional modeling is the presence of the high relativistic factor values (the field gradients are high), the convergence conditions for PIC method and the necessary number of particles in 3D cell. Thus the parallel algorithm is based on the mixed Euler-Lagrangian decomposition in order to achieve good load balancing, and demonstrates the high scalability. With the advances of the code it will be possible to apply it for one-passage beam-beam simulations in linear colliders with supercritical parameters. We present the results of numerical simulations of colliding beams using dummy parameters and parameters close to the ones of the newest ILC project.
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MOPME029	Simulation of Low Energy Charged Particle Beams	442
	O. Karamyshev, C.P. Welsch Cockcroft Institute, Warrington, Cheshire, United Kingdom O. Karamyshev, C.P. Welsch The University of Liverpool, Liverpool, United Kingdom
	Low energy particle beams pose specific challenges to simulation codes and experiments alike as a number of effects become important that can often be neglected at higher beam energies, including e.g. space-charge or fringe field effects. The optimization of low energy charged particle beam transport through arbitrary electromagnetic fields is the purpose of a code aimed at tracking low-energy particles from the sub-eV to the MeV energy range with high precision. The code is based on Matlab/Simulink and able to use 3-dimensional field maps from either Finite Elements Method (FEM) solvers, such as Comsol, OPERA 3D or CST particle studio, fields calculated by the code itself, or field maps from measurements. This contribution describes the code structure and presents its performance limitations. It also gives a summary of results obtained from beam dynamics simulations of cyclotrons injection systems, storage ring extraction systems, electrostatic and magnetic beamlines, as well as from photocathode optimization studies.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPME029
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MOPME031	SolCalc: A Suite for the Calculation and the Display of Magnetic Fields Generated by Solenoid Systems	445
	M.L. Lopes Fermilab, Batavia, Illinois, USA
	SolCalc is a software suite that computes and displays magnetic fields generated by a three dimensional (3D) solenoid system. Examples of such systems are the Mu2e magnet system and Helical Solenoids for muon cooling systems. SolCalc was originally coded in Matlab, and later upgraded to a compiled version (called MEX) to improve solving speed. Matlab was chosen because its graphical capabilities represent an attractive feature over other computer languages. Solenoid geometries can be created using any text editor or spread sheets and can be displayed dynamically in 3D. Fields are computed from any given list of coordinates. The field distribution on the surfaces of the coils can be displayed as well. SolCalc was benchmarked against a well-known commercial software for speed and accuracy and the results compared favorably.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPME031
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MOPME032	PIC Simulations in Low Energy Part of PIP-II Proton Linac	448
	G.V. Romanov Fermilab, Batavia, Illinois, USA
	The front end of PIP-II linac is composed of a 30 keV ion source, low energy beam transport line (LEBT), 2.1 MeV radio frequency quadrupole (RFQ), and medium energy beam transport line (MEBT). This configuration is currently being assembled at Fermilab to support a complete systems test. The front end represents the primary technical risk with PIP-II, and so this step will validate the concept and demonstrate that the hardware can meet the specified requirements. SC accelerating cavities right after MEBT require high quality and well defined beam after RFQ to avoid excessive particle losses. In this paper we will present recent progress of beam dynamic study, using CST PIC simulation code, to investigate partial neutralization effect in LEBT, halo and tail formation in RFQ, total emittance growth and beam losses along low energy part of the linac.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPME032
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MOPME033	Beam Dynamics in an Electron Lens with the Warp Particle-in-cell Code	451
	G. Stancari Fermilab, Batavia, Illinois, USA V. Moens EPFL, Lausanne, Switzerland S. Redaelli CERN, Geneva, Switzerland
	Funding: Fermi Research Alliance, LLC operates Fermilab under Contract DE-AC02-07CH11359 with the US Department of Energy. Research supported in part by US LARP and EU FP7 HiLumi LHC, Grant Agreement 284404. Electron lenses are a mature technique for beam manipulation in colliders and storage rings. In an electron lens, a pulsed, magnetically confined electron beam with a given current-density profile interacts with the circulating beam to obtain the desired effect. Electron lenses were used in the Fermilab Tevatron collider for beam-beam compensation, for abort-gap clearing, and for halo scraping. They will be used in RHIC at BNL for head-on beam-beam compensation, and their application to the Large Hadron Collider for halo control is under development. At Fermilab, electron lenses will be implemented as lattice elements for nonlinear integrable optics. The design of electron lenses requires tools to calculate the kicks and wakefields experienced by the circulating beam. We use the Warp particle-in-cell code to study generation, transport, and evolution of the electron beam. For the first time, a fully 3-dimensional code is used for this purpose.
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MOPME035	Current Status of the GPU-Accelerated ELEGANT	454
	I.V. Pogorelov, K.M. Amyx, J.R. King Tech-X, Boulder, Colorado, USA M. Borland, R. Soliday ANL, Argonne, Ilinois, USA
	Funding: Work supported by the DOE Office of Science, Office of Basic Energy Sciences grant No. DE-SC0004585, and in part by Tech-X Corporation. Efficient implementation of general-purpose particle tracking on GPUs can result in significant performance benefits to large-scale tracking simulations. This presentation is an update on the current status of our work on accelerating Argonne National Lab’s particle accelerator simulation code ELEGANT using CUDA-enabled GPU. We summarize the performance of beamline elements ported to GPU, and discuss optimization techniques for some important collective effects kernels, in particular our methods of avoiding costly thread contention. We also present preliminary results of a scaling study of the GPU-accelerated version of the code.
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MOPME037	The Development of Stochastic Processes in COSY Infinity	457
	J.D. Kunz IIT, Chicago, Illinois, USA M. Berz, K. Makino MSU, East Lansing, Michigan, USA P. Snopok Illinois Institute of Technology, Chicago, Illlinois, USA
	Funding: Work supported by U.S. Department of Energy. COSY Infinity is an arbitrary-order beam dynamics simulation code. It can determine high-order transfer maps of combinations of particle optical elements. New features are being developed for inclusion in COSY to follow the distribution of particles through matter. To study in detail the properties of muons passing through material, the transfer map approach alone is not sufficient. The interplay of beam optics and atomic processes must be studied by a hybrid transfer map–Monte-Carlo approach in which transfer map methods describe the average behavior of the particles including energy loss, and Monte-Carlo methods are used to provide small corrections to the predictions of the transfer map accounting for the stochastic nature of scattering and straggling of particles. The advantage of the new approach is that the vast majority of the dynamics is represented by fast application of the high-order transfer map of an entire element and accumulated stochastic effects. The gains in speed will aid the optimization of muon cooling channels. Progress on the development of the required algorithms is reported.
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MOPME038	Space Charge Simulation in COSY using The Fast Multipole Method	460
	B.T. Loseth, M. Berz, K. Makino MSU, East Lansing, Michigan, USA P. Snopok Fermilab, Batavia, Illinois, USA H. Zhang JLab, Newport News, Virginia, USA
	A method is implemented in COSY Infinity that allows the computation of space charge effects of arbitrary and large distributions of particles in an efficient and accurate way based on a variant of the Fast Multipole Method (FMM). It relies on an automatic multigrid-based decomposition of charges in near and far regions and the use of high-order differential algebra methods to obtain decompositions of far fields that lead to an error that scales with a high power of the order. Given an ensemble of N particles, the method allows the computation of the self-fields of all particles on each other with a computational expense that scales as O(N). Furthermore, the method allows the computation of all high-order multipoles of the space charge fields that are necessary for the computation of high-order transfer maps and all resulting aberrations. Space charge effects are crucial in modeling the latter stages of the six-dimensional (6D) cooling channel for the Muon Collider. Results of simulating the 6D cooling channel for the Muon Collider using the FMM method and other tools and improvements implemented for ionization cooling lattices are presented.
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MOPME040	MadFLUKA Beam Line 3D Builder. Simulation of Beam Loss Propagation in Accelerators	463
	M. Santana-Leitner, Y. Nosochkov, T.O. Raubenheimer SLAC, Menlo Park, California, USA
	Funding: This work was supported by Department of Energy contract DE-AC02-76-SFO0515 Beam tracking programs provide information of orbits along the nominal trajectory to design beam-line optics. Other aspects like machine or radiation protection, which inspect the transverse dimensions and volumes, are simulated with radiation transport Monte Carlo codes, some of which also include magnetic tracking capabilities. Evaluation of certain aspects, like beam loss shower induced propagation along a beam line, or beam mis-steering phase-space, would require to combine features of both types of codes, or use the latter ones with full accelerator 3D implementations, often too cumbersome and time consuming. This paper presents MadFLUKA, a program that produces FLUKA compatible geometries from MAD files. Objects selected from a user user-configurable database are auto-replicated with the rules of ‘twiss’ and ‘survey’ files to create beam lines with hundreds of components. FLUKA magnetic subroutine is generated from MAD optics, including history randomization of fields for ray-trace analysis of mis-steering failures. MadFLUKA is used in the design of the LCLS-II, at SLAC.
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MOPME043	Modeling and Simulation of Beam-induced Plasma in Muon Cooling Devices	466
	K. Yu SBU, Stony Brook, USA M. Chung, A.V. Tollestrup, K. Yonehara Fermilab, Batavia, Illinois, USA B.T. Freemire IIT, Chicago, Illinois, USA V. Samulyak BNL, Upton, Long Island, New York, USA V. Samulyak SUNY SB, Stony Brook, New York, USA
	Understanding of the interaction of muon beams with plasma in muon cooling devices is important for the optimization of the muon cooling process. We have developed numerical algorithms and parallel software for self-consistent simulation of the plasma production and its interaction with particle beams and external fields. Simulations support the experimental program on the hydrogen gas filled RF cavities in the Mucool Test Area (MTA) at Fermilab. Computational algorithms are based on the electromagnetic particle-in-cell (PIC) code SPACE combined with a probabilistic, macroparticle-based implementation of atomic physics processes such as the absorption of the incident particles, ionization of the absorber material, and the generation and evolution of secondary particles in dense, neutral gas. In particular, we have proposed a novel algorithm for dealing with repetitive incident beam, enabling simulations of long time scale processes. Benchmarks and simulations of the experiments on gas-filled RF cavities and prediction for future experiments are discussed. * kwangmin.yu@stonybrook.edu ** rosamu@bnl.gov
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MOPRI069	Computing Angularly-resolved Far Field Emission Spectra in Particle-in-cell Codes using GPUs	761
	R.G. Pausch, H. Burau, M.H. Bussmann, J.P. Couperus, A.D. Debus, A. Huebl, A. Irman, A. Köhler, U. Schramm, K. Steiniger, R. Widera Helmholtz-Zentrum Dresden-Rossendorf (HZDR), Institute of Radiation Physics, Dresden, Germany T.E. Cowan HZDR, Dresden, Germany
	Angularly resolved far field radiation spectra computed from the Lienard Wiechert Potentials of accelerated electrons give information on the microscopic particle dynamics. We present recent results using our many-GPU, fully relativistic 3D3V particle-in-cell code PIConGPU for which we have developed fully synthetic radiation diagnostics that is capable of computing angularly-resolved radiation spectra of more than 10¹⁰ electrons for several hundred to a thousand wavelengths and directions in a single simulation in less than a day on large-scale supercomputers. With such a technique it is possible to use precision spectroscopic methods for understanding the dynamics of electron acceleration in scenarios where other diagnostics fail. We present studies on laser-driven wakefield acceleration and astrophysical jet dynamics to underline the power of this new technique.
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TUXB01	Recent Progress in 3D Numerical Wakefield Calculations	944
	W. Bruns WBFB, Berlin, Germany
	The 3D electromagnetic Field Simulator GdfidL computes Wakepotentials on standard CPUs with a Speed comparable to GPU-Based Implementations. This is achieved via Computing only in interesting Cells, having the FD-Coefficients in compressed Form, traversing the Grid in a Cache-friendly Order and applying a blocked Update Scheme which is NuMA-aware. A Dispersion optimised Scheme is described. Fields in dispersive Materials are computed via solving the Equations of the Electron Hulls of the Material. Moving Mesh Computations have the Grid-generation on the Fly.
	Slides TUXB01 [16.169 MB]
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TUOAB01	Computation of Eigenmodes in Long and Complex Accelerating Structures by Means of Concatenation Strategies	947
	T. Flisgen, J. Heller, U. van Rienen Rostock University, Faculty of Computer Science and Electrical Engineering, Rostock, Germany
	Funding: This research was partially funded by the EuCARD project which is co-funded by European Commission 7th in Framework Programme (FP7). The computation of eigenmodes for complex accelerating structures is a challenging and important task for the design and operation of particle accelerators. Discretizing long and complex structures to determine its eigenmodes leads to demanding computations typically performed on super computers. This contribution presents an application example of a method to compute eigenmodes and other parameters derived from these eigenmodes for long and complex structures using standard workstation computers. This is accomplished by the decomposition of the complex structure into several single segments. In a next step, the electromagnetic properties of the segments are described in terms of a compact state space model. Subsequently, the state space models of the single structures are concatenated to the full structure. The results of direct calculations are compared with results obtained by the concatenation scheme in terms of computational time and accuracy.
	Slides TUOAB01 [1.781 MB]
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Paper

Title

Page

GPU-Accelerated Long-Term Simulations of Beam-Beam Effects in Colliders

77

B. Terzić, F. Lin, V.S. Morozov, Y. Roblin, H. Zhang
JLab, Newport News, Virginia, USA
M. Aturban, D. Ranjan, M. Zubair
ODU CS, Norfolk, Virginia, USA

Funding: Authored by Jefferson Science Associates, LLC under U.S. DOE Contract No. DE-AC05-06OR23177.
We present an update on the development of the new code for long-term simulation of beam-beam effects in particle colliders. The underlying physical model relies on a matrix-based arbitrary-order particle tracking (including a symplectic option) for beam transport and the generalized Bassetti-Erskine approximation for beam-beam interaction. The computations are accelerated through a parallel implementation on a hybrid GPU/CPU platform. With the new code, previously computationally prohibitive long-term simulations become tractable. The new code will be used to model the proposed Medium-energy Electron-Ion Collider (MEIC) at Jefferson Lab.

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MOPRO067

Analytic Calculation of Electric Fields of Coherent THz Pulses

234

M. Schwarz, P. Basler, M. Guenther, A.-S. Müller, M. von Borstel
KIT, Karlsruhe, Germany
M.T. Schmelling
MPI-K, Heidelberg, Germany

The coherently emitted electric field pulse of a short electron bunch is obtained by summing the fields of the individual electrons, taking phase differences due to different longitudinal positions into account. For an electron density, this sum becomes an integral over the charge density and frequency spectrum of the emitted radiation, which, however, is difficult to evaluate numerically. In this paper, we present a fast analytic method valid for arbitrary bunch shapes. We also include shielding effects of the beam pipe and consider ultra-short bunches, where the high frequency part of the coherent synchrotron spectrum is cut-off not by the inverse bunch length but by the critical frequency of synchrotron radiation. Our technique is applied to bunches, simulated simulated for the linac-based FLUTE accelerator test facility at KIT.

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MOPRO095

Application Program for Automatically Getting the First Turn and Closed Orbit in TPS Commissioning

310

M.-S. Chiu, H.-P. Chang, P.J. Chou, F.H. Tseng
NSRRC, Hsinchu, Taiwan

Taiwan Photon Source (TPS) is a 3 GeV third generation electron synchrotron light source, consist of 5 major modules: LINAC, LTB transfer line, booster ring, BTS transfer line and storage ring. Its beam commissioning is scheduled in 2014. Getting the first turn and approaching the closed orbit is a crucial step for achieving stored beam in ring-based accelerator commissioning. In order to make first turn beam commissioning efficient, we develop a MATLAB-based application program based on AT and MML for automatic beam steering and closed orbit search. The algorithm and simulation results are presented.

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MOPME002

Simulation of the Thermal Deformation and the Cooling of a Four-rod Radio Frequency Quadrupole

376

B. Masschaele, H. De Gersem, T. Roggen
KU Leuven, Kortrijk, Belgium
H. Podlech
IAP, Frankfurt am Main, Germany
D. Vandeplassche
SCK•CEN, Mol, Belgium

Funding: This work is supported by the European Atomic Energy Community’s Seventh Framework Programme under grant agreement nr. 269565 (MAX project).
A four-rod radio frequency quadrupole (RFQ) contains four modulated rods kept in place by a number of stems and fixed within a resonating cavity. The position and the modulation of the rods determines the focusing and accelerating properties of the RFQ. The resonating field induces currents, and by that Joule losses, in the stems, rods and tuning plates. The temperature increase causes a mechanical deformation which may lead to a deteriorated performance of the RFQ. The temperature increase is kept small by cooling the rods and stems. A new layout of cooling channels has been proposed. The paper reports about coupled electromagnetic, fluid-dynamic, thermal and structural dynamic field simulations carried out for predicting the mechanical deformation of the stems and the rods. The results for the four-rod RFQ planned for the MYRRHA proton accelerator indicate a change of 47 μm of the distance between the rods when cooling water with a velocity of 3 m/s is applied.

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MOPME003

Radio Frequency Quadrupole Surrogate Field Models Based on 3D Electromagnetic Field Simulation Results

379

T. Roggen, H. De Gersem, B. Masschaele
KU Leuven, Kortrijk, Belgium
W. Ackermann, S. Franke, T. Weiland
TEMF, TU Darmstadt, Darmstadt, Germany

Funding: This research is funded by grant ”KUL 3E100118” ”Electromagnetic Field Simulation for Future Particle Accelerators”, Project FP7-Euratom No. 269565 and the Belgian Nuclear Research Centre (SCK•CEN)
Surrogate field models for the different sections of a Radio Frequency Quadrupole (RFQ) are developed, identified on the basis of finite element (FE) simulation and embedded in a moment method beam dynamics simulation code. The models are validated for both theoretical and realistic RFQ designs.

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MOPME004

RFQ Solver based on the Method of Moments

382

C. Raucy, C.V.G. Craeye
UCL, Louvain-la-Neuve, Belgium
D. Vandeplassche
SCK•CEN, Mol, Belgium

Funding: SCK•CEN
The aim of this research is to improve the accuracy and the simulation time of solvers devoted to Radio Frequency Quadrupoles (RFQ). The Method of Moments is a full-wave method used to solve scattering problems. Its main advantage over FE or FDTD solvers is that unknowns are limited to the boundaries of the object. The resulting dense system of equations can be solved very rapidly with the help of domain-decomposition approaches (e.g. Macro Basis Functions*), especially when the level of detail is very fine compared to the wavelength, which is definitely the case for RFQ’s. Such a method however needs a first regularization method to overcome the low-frequency breakdown in order to compute the Macro Basis Functions. The respective field contributions of different parts of the global structure (e.g. rods vs. stems) can also easily be finely investigated. Numerical results will be presented based on the Myrrha RFQ. The low-frequency breakdown issue due to the very fine mesh will be discussed and a solution based on the so-called Loop-Tree** decomposition will be detailed.
* Ozdemir, N.A.; Gonzalez-Ovejero, D.; Craeye, C., IEEE Tr.AP, vol.61, no.4, pp.2088, 2098, April 2013
** Andriulli, F.P., IEEE Tr.AP, vol.60, no.5, pp.2347, 2356, May 2012

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MOPME005

Simulation of the Extraction and Transport of a Beam from the SILHI Source with the Warp Code

385

A. Chancé, N. Chauvin
CEA/DSM/IRFU, France

In a low energy beam transfer (LEBT) line, space charge effects are dominant and make the motion of the particles strongly non-linear. So, the beam dynamics is directly dependent on the 6D distribution of the particles after the ion source extraction system. It is thus essential to simulate accurately the source extraction region and the space charge compensation after it to try to reach an agreement between the simulations and the measurements. Generally, the ion source extraction system is simulated with electrostatic codes (often using simple model for space charge) from which the 6D beam distribution is derived. Then, this distribution can be used as an initial condition to simulate the beam transport in the LEBT with a time dependent PIC code that takes into account space charge compensation. We propose here to simulate accurately the SILHI source extraction system with the Warp and AXCEL-INP codes. The SILHI ion source will be quickly presented and some simulations results will be given and discussed.

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MOPME007

Multi-objective Optimization of the Linear and Non-linear Beam Dynamics of Synchrotron SOLEIL

388

X.N. Gavaldà, A. Díaz Ortiz, L.S. Nadolski
SOLEIL, Gif-sur-Yvette, France

One of the most important challenges for the actual and new third generation of synchrotron light sources is to optimize the linear and the non-linear beam dynamics of these strong focusing lattices. The optimization of a storage ring lattice is a multi-objective problem that involves a high number of constraints in a multi-dimensional parameter space. In this paper we used Multi-Objective Genetic Algorithm (MOGA) and the tracking code ELEGANT to optimize the linear and non-linear beam dynamics of the SOLEIL synchrotron light source. The objectives of our optimization are the dynamical aperture and the momentum aperture which are strongly correlated to the injection efficiency and the Touschek lifetime, respectively. This paper will discuss the deployment of this computational approach using the SOLEIL computer cluster. The first results will also be presented and we will discuss possible improvements.

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MOPME008

3d Full Electromagnetic Beam Dynamics Simulations of the Pitz Photoinjector

391

Y. Chen, E. Gjonaj, W.F.O. Müller, T. Weiland
TEMF, TU Darmstadt, Darmstadt, Germany

Funding: work supported by DESY, Hamburg and Zeuthen sites
The electromagnetic (EM) simulation software CST STUDIO SUITE® * has been applied to investigate the beam dynamics for the electron gun of the Photo Injector Test facility at DESY, Zeuthen site (PITZ). A series of 3D beam dynamics simulations are performed to study the bunch injection process at PITZ with the objective of clarifying the discrepancies between measurements and simulations. Multiple comparisons are presented for the transverse emittance and the total emitted charge between the measurement data and simulation results using CST STUDIO SUITE®and Astra **.
* Computer Simulation Technology AG, website: http://www.cst.com/
** K. Floettmann A Space Charge Tracking Algorithm, user manual (version 3), 2011

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MOPME009

Numerical Calculation of Electromagnetic Fields in Acceleration Cavities under Precise Consideration of Coupler Structures

394

C. Liu, W.A. Ackermann2, W.F.O. Müller, T. Weiland
TEMF, TU Darmstadt, Darmstadt, Germany

Funding: Work supported by BMBF under contract 05H12RD5
During the design phase of superconducting radio frequency (RF) accelerating cavities a challenging and difficult task is to determine the electromagnetic field distribution inside the structure with the help of proper computer simulations. Although dissipation due to lossy materials is neglected in the current work, in reality, because energy transfer appears due to the design of the superconducting cavities, the numerical eigenmode analysis based on real-valued variables is no longer suitable to describe the dissipative acceleration structure. Dissipation can appear with the help of dedicated higher order mode (HOM) couplers, the power coupler as well as the beam tube once the resonance frequency is above the cutoff frequency of the corresponding waveguide. At the Computational Electromagnetics Laboratory (TEMF) a robust parallel eigenmode solver based on complex-valued finite element analysis is available. The eigenmode solver has been applied to the TESLA 1.3 GHz and the third harmonic 3.9 GHz nine-cell cavities to determine the resonance frequency, the quality factor and the corresponding field distribution of eigenmodes.

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MOPME010

A MAD-X Model of the HIT Accelerator

397

R. Cee, M. Galonska, T. Gläßle, Th. Haberer, K. Höppner, A. Peters, S. Scheloske
HIT, Heidelberg, Germany

For a medical accelerator facility like the Heidelberg Ion-Beam Therapy Centre (HIT) an online simulation tool with read and write access to the control system and the database is essential for effective beam alignment and beam spot size adjustment at the patient position. Since the commissioning of HIT the simulation programme Mirko from GSI Darmstadt has been in use for the simulation of the beamlines and the synchrotron. While Mirko fully complies with the demands and is still in regular use, the long-term support of the HIT-Mirko derivate cannot be guaranteed. We have therefore started to set up a new simulation environment based on the MAD-X programme from CERN. In a first step we built a MAD-X model of the HIT accelerator using the MAD-X export function of Mirko. The resulting sequences were transformed and extended into executable MAD-X files. The simulation results were validated against Mirko and a good agreement of the calculated beam envelopes could be achieved. Works on the graphical user interface (GUI) for visualisation of and interaction with the beam envelopes and the link to the control system are in progress.

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MOPME011

Matrix Integration of ODEs for Spin-orbit Dynamics Simulation

400

SUSPSNE063

use link to see paper's listing under its alternate paper code

A.N. Ivanov, Y. Senichev
FZJ, Jülich, Germany

MODE (Matrix integration of Ordinary Differential Equations) is a software package that provides nonlinear matrix maps building for spin-orbit beam dynamics simulation. In this article we briefly describe the developed integrated development environment features and present computational comparison with other simulation tools. MODE mathematical model is based on Newton-Lorentz and T-BMT equations that are expanded to Taylor series up to the necessary order of nonlinearity. The numerical algorithm is based on matrix presentation of Lie propagator. Spin-orbit simulation results of MODE are compared with results of COSY Infinity and OptiM. MODE provides a flexible graphic user interface, code auto complete technology and visual designer for accelerators. There is also a possibility to generate codes in different programming languages and parallelization techniques.

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MOPME012

A New Tool for Automated Orbit and Spin Motion Analysis

403

SUSPSNE066

use link to see paper's listing under its alternate paper code

D. Zyuzin
FZJ, Jülich, Germany

There are a lot of tools to simulate beam dynamics in accelerators of various types. Many of them are intended to use for specific purposes, and there are universal codes that can simulate both orbit and spin motion in magnetic and electrostatic structures. To start using these codes beam physicist first should have learn syntax, know features and methods how to describe lattice and beams in this particular code. Output data structures of different simulation programs are also vary and depend on peculiarities of each program. This paper proposes a new tool for automated generation and execution of input files for simulation programs and for data analysis of output data. The developed tool allows to describe a lattice, calculate different lattice parameters (like tunes) using simulation program, track particles inside the lattice and analyze various parameters of output data (like beam depolarization). Simulations and analysis can be done in parallel using built-in parallelization mechanisms, and all results can be stored in the database and can be easily fetched when needed. The tool is used to simulate beam and spin dynamics in different lattices to increase spin coherence time.

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MOPME013

A Python Poisson Solver for 3D Space Charge Computations in Structures with Arbitrary Shaped Boundaries

406

G. Pöplau, C. Potratz
COMPAEC e.G., Rostock, Germany

Numerical techniques in the field of particle accelerators are mainly driven by the design of next-generation accelerators: The need for higher simulation complexity and the necessity for more and more specialized algorithms arises from the ever increasing need to include a broader range of physical effects and geometrical details in a computer simulation. This, on the other hand requires fast and reliable simulation tools for a limited user base. Therefore, new approaches in simulation software development are necessary to provide useful tools that are well-suited for the task at hand and that can be easily maintained and adapted by a small user community. We show how Python can be used to solve numerical problems arising from particle accelerator design efficiently. As model problem, the computation of space charge effects of a bunch in RFQs including the vane geometry was chosen and a suited solver was implemented in Python.

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MOPME014

Automated Mode Recognition Algorithm for Accelerating Cavities

409

K. Brackebusch, T. Galek, 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 contract 05K13HR1.
Eigenmode simulations of accelerating structures often involve a large number of computed modes that need to be catalogued and compared. In order to effectively process all the information gathered from eigenmode simulations a new algorithm was developed to automatically recognize modes’ field patterns. In this paper we present the principles of the algorithm and investigate its applicability by means of different single and multi cell cavities. The highest achievable order of correctly recognized modes is of particular interest.

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MOPME017

Study of Higher Order Modes in Multi-Cell Cavities for BESSY-VSR Upgrade

412

T. Galek, K. Brackebusch, Sh. Gorgi Zadeh, 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 contract 05K13HR1.
BESSY-VSR is a planned scheme to upgrade the existing BESSY II storage ring to support variable electron pulse lengths. In addition to the present 0.5 GHz energy replenishment cavity, two additional SRF bunch compressing cavities operating at 1.5 GHz (3rd harmonic) and 1.75 GHz (sub-harmonic), will be installed. These cavities are essential to produce short 1.5 ps bunches with current of up to 0.8 mA per bunch. In order to achieve such high beam currents, higher order modes must be damped in the superconducting cavities. In this work we present analysis of higher order modes in cavities with different mid-cell shapes.

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MOPME018

Quantification of Geometric Uncertainties in Single Cell Cavities for BESSY VSR using Polynomial Chaos

415

SUSPSNE062

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J. Heller, T. Flisgen, C. Schmidt, U. van Rienen
Rostock University, Faculty of Computer Science and Electrical Engineering, Rostock, Germany

Funding: Federal Ministry for Research and Education Germany under contract 05K13HR1
The electromagnetic properties of SRF cavities are mostly determined by their shape. Due to fabrication tolerances, tuning and limited resolution of measurement systems, the exact shape remains uncertain. In order to make assessments for the real life behaviour it is important to quantify how these geometrical uncertainties propagate through the mathematical system and influence certain electromagnetic properties, like the resonant frequencies of the structure's eigenmodes. This can be done by using non-intrusive straightforward methods like Monte-Carlo (MC) simulations. However, such simulations require a large number of deterministic problem solutions to obtain a sufficient accuracy. In order to avoid this scaling behaviour, the so-called polynomial chaos (PC) expansion is used. This technique allows for the relatively fast computation of uncertainty propagation for few uncertain parameters in the case of computationally expensive deterministic models. In this paper we use the PC expansion to quantify the propagation of uncertain geometry on the example of single cell cavities used for BESSY VSR as well as to compare the obtained results with the MC simulation.

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MOPME019

Study of a Fast Convolution Method for Solving the Space Charge Fields of Charged Particle Bunches

418

D. Zheng, A. Markoviḱ, G. Pöplau, U. van Rienen
Rostock University, Faculty of Computer Science and Electrical Engineering, Rostock, Germany

The kernel of beam dynamics simulations using the particle-in-cell (PIC) model is the solution of Poisson's equation for the electric potential. A very common way to solve Poisson's equation is to use the convolution of charge density and Green's function, the so-called Green's function method. Additionally, the integrated Green's function method* is being used in order to achieve a higher accuracy. For both methods, the convolutions are done using fast Fourier transform based on the convolution theorem. However, the construction of the integrated Green's function and the further convolution is still very time-consuming. The computation can be accelerated without loosing precision if the calculation of Green’s function values is limited to that part of the computational domain with non-zero grid charge density. In this paper we present a general numerical study of these Green's function methods for computing the potential of different bunches: The results can also be used in other simulation codes to improve efficiency.
* J. Qiang, S. Lidia, R. D. Ryne, and C. Limborg-Deprey, “A Three-Dimensional Quasi-Static Model for High Brightness Beam Dynamics simulation,” Phys. Rev. ST Accel. Beams, vol 9, 044204 (2006).

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MOPME021

Vicky: Computer Code Update

421

F. Iazzourene
Elettra-Sincrotrone Trieste S.C.p.A., Basovizza, Italy

Vicky is a computer code for designing and simulating charged particle accelerators*. We recall mainly that Vicky is a very user friendly code, the particle motion is described by 10 parameters: four beta-functions, four alpha-functions and two phase advances, and a large variety of insertion devices, wigglers and undulators, linearly and elliptically polarized, are treated. The features include Twiss functions matching, orbit correction, tune and chromaticity adjustment, dynamic aperture and phase space tracking. The paper describes new aspects and the present status.
* F. IAZZOURENE, “Vicky: A Computer Code for Use in the Design and Simulation of Particle Accelerators”, proceedings IPAC 2011.

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MOPME022

Investigation of the Breakdown and RF Sheath Potential for EAST ICRF Antenna

424

H. Yang, S. Dong, L. Shang, K. Tang, C.-F. Wu
USTC/NSRL, Hefei, Anhui, People's Republic of China

A new ion cyclotron range of frequency (ICRF) antenna was designed with four current straps in Experimental Advanced Superconducting Tokamak (EAST). It is to provide heating, current drive and some physics experiments in EAST. The breakdown and RF sheath potential for the antenna are investigated by a three dimension electromagnetic code in the paper. The plasma is simulated by a slab with high relative permittivity approximating the plasma loading of the antenna. Calculations show that the maximum of electric field is around the end of the coaxial feeds and the strip line and the electric field is strongly dependent on antenna phasing. Especially the maximum of electric field is decreased to 27.5 KV/cm with the (0,π,π,0) phasing between toroidal straps while the value is 32.8 KV/cm with (0,0,π,π) phasing. A challenge in ICRF is the impurity contamination which is related to sheath potential. The topology of the radio frequency (RF) sheath is optimized to reduce the potential for EAST ICRF antenna. The RF potential is mitigated obviously with the broader side limiter by a factor of 2.

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MOPME023

A High Precision Particle-moving Algorithm for Particle-in-cell Simulation of Plasma

427

SUSPSNE064

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X.F. Li, D.Z. Chen, D. Li, H.K. Yue
HUST, Wuhan, People's Republic of China

A new particle-moving algorithm for particle-in-cell simulation of plasma is developed based on the Linear Multistep Method. The conventional and the new algorithms are investigated by numerical experiments, which are conducted in three typical fashions of the electron motions in electromagnetic fields, that is, cyclotron in homogeneous magnetic field, drift in field and motions in inhomogeneous magnetic field. The new algorithm not only improves the accuracy but also relaxes the time step condition for the simulation. It can increase the computation efficiency.

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MOPME025

New Possibilities of MultP-M Code

433

M. Gusarova, S. Khudyakov, I.I. Petrushina, Ya.V. Shashkov
MEPhI, Moscow, Russia

Implementation and Testing of the new module package for geometry import of the MultP-M 3D code for multipacting prediction was performed. The results of simulations for the coaxial line specimen using this new module are presented. These results are compared with analytical calculations and experimental data.

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MOPME026

IBS Simulations with Compute Unified Device Architecture (CUDA) Technology

436

S.A. Glukhov, E.B. Levichev, S.A. Nikitin, P.A. Piminov, D.N. Shatilov, S.V. Sinyatkin
BINP SB RAS, Novosibirsk, Russia

A program code for 6D tracking has been developed taking into account IBS (Intra-Beam Scattering) and Touschek effect and using Monte-Carlo method. The simulation algorithm has been developed on the basis of well-known IBS theory presented in (*). The resulting program can be executed using GPGPU devices (General-Purpose Graphics Processing Units) supporting CUDA technology (Compute Unified Device Architecture).
* J. Le Duff, Single and multiple Touschek effects // Published in In Rhodos 1993, Advanced accelerator physics, vol. 2 573-586. CERN Geneva - CERN-95-06 (95/11,rec. Mar.96) 1993. p. 573-586.

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MOPME027

Parallel Three-dimensional PIC Code for Beam-beam Simulation in Linear Colliders

439

M.A. Boronina, V.D. Korneev, V.A. Vshivkov
ICM&MG SB RAS, Novosibirsk, Russia

We present our parallel 3D3V particle-in-cell code for the numerical simulations of ultrarelativistic charged beams in supercolliders. In the algorithm we employ the three-dimensional set of Maxwell equations and the Vlasov-Liouville equation for the distribution function of beam particles in 6-dimensional phase space. The code allows performing numerical experiments with an arbitrary density distribution, beam crossing angle and relative offset. From the mathematical point of view the main problem of the three-dimensional modeling is the presence of the high relativistic factor values (the field gradients are high), the convergence conditions for PIC method and the necessary number of particles in 3D cell. Thus the parallel algorithm is based on the mixed Euler-Lagrangian decomposition in order to achieve good load balancing, and demonstrates the high scalability. With the advances of the code it will be possible to apply it for one-passage beam-beam simulations in linear colliders with supercritical parameters. We present the results of numerical simulations of colliding beams using dummy parameters and parameters close to the ones of the newest ILC project.

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MOPME029

Simulation of Low Energy Charged Particle Beams

442

O. Karamyshev, C.P. Welsch
Cockcroft Institute, Warrington, Cheshire, United Kingdom
O. Karamyshev, C.P. Welsch
The University of Liverpool, Liverpool, United Kingdom

Low energy particle beams pose specific challenges to simulation codes and experiments alike as a number of effects become important that can often be neglected at higher beam energies, including e.g. space-charge or fringe field effects. The optimization of low energy charged particle beam transport through arbitrary electromagnetic fields is the purpose of a code aimed at tracking low-energy particles from the sub-eV to the MeV energy range with high precision. The code is based on Matlab/Simulink and able to use 3-dimensional field maps from either Finite Elements Method (FEM) solvers, such as Comsol, OPERA 3D or CST particle studio, fields calculated by the code itself, or field maps from measurements. This contribution describes the code structure and presents its performance limitations. It also gives a summary of results obtained from beam dynamics simulations of cyclotrons injection systems, storage ring extraction systems, electrostatic and magnetic beamlines, as well as from photocathode optimization studies.

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MOPME031

SolCalc: A Suite for the Calculation and the Display of Magnetic Fields Generated by Solenoid Systems

445

M.L. Lopes
Fermilab, Batavia, Illinois, USA

SolCalc is a software suite that computes and displays magnetic fields generated by a three dimensional (3D) solenoid system. Examples of such systems are the Mu2e magnet system and Helical Solenoids for muon cooling systems. SolCalc was originally coded in Matlab, and later upgraded to a compiled version (called MEX) to improve solving speed. Matlab was chosen because its graphical capabilities represent an attractive feature over other computer languages. Solenoid geometries can be created using any text editor or spread sheets and can be displayed dynamically in 3D. Fields are computed from any given list of coordinates. The field distribution on the surfaces of the coils can be displayed as well. SolCalc was benchmarked against a well-known commercial software for speed and accuracy and the results compared favorably.

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MOPME032

PIC Simulations in Low Energy Part of PIP-II Proton Linac

448

G.V. Romanov
Fermilab, Batavia, Illinois, USA

The front end of PIP-II linac is composed of a 30 keV ion source, low energy beam transport line (LEBT), 2.1 MeV radio frequency quadrupole (RFQ), and medium energy beam transport line (MEBT). This configuration is currently being assembled at Fermilab to support a complete systems test. The front end represents the primary technical risk with PIP-II, and so this step will validate the concept and demonstrate that the hardware can meet the specified requirements. SC accelerating cavities right after MEBT require high quality and well defined beam after RFQ to avoid excessive particle losses. In this paper we will present recent progress of beam dynamic study, using CST PIC simulation code, to investigate partial neutralization effect in LEBT, halo and tail formation in RFQ, total emittance growth and beam losses along low energy part of the linac.

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MOPME033

Beam Dynamics in an Electron Lens with the Warp Particle-in-cell Code

451

G. Stancari
Fermilab, Batavia, Illinois, USA
V. Moens
EPFL, Lausanne, Switzerland
S. Redaelli
CERN, Geneva, Switzerland

Funding: Fermi Research Alliance, LLC operates Fermilab under Contract DE-AC02-07CH11359 with the US Department of Energy. Research supported in part by US LARP and EU FP7 HiLumi LHC, Grant Agreement 284404.
Electron lenses are a mature technique for beam manipulation in colliders and storage rings. In an electron lens, a pulsed, magnetically confined electron beam with a given current-density profile interacts with the circulating beam to obtain the desired effect. Electron lenses were used in the Fermilab Tevatron collider for beam-beam compensation, for abort-gap clearing, and for halo scraping. They will be used in RHIC at BNL for head-on beam-beam compensation, and their application to the Large Hadron Collider for halo control is under development. At Fermilab, electron lenses will be implemented as lattice elements for nonlinear integrable optics. The design of electron lenses requires tools to calculate the kicks and wakefields experienced by the circulating beam. We use the Warp particle-in-cell code to study generation, transport, and evolution of the electron beam. For the first time, a fully 3-dimensional code is used for this purpose.

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MOPME035

Current Status of the GPU-Accelerated ELEGANT

454

I.V. Pogorelov, K.M. Amyx, J.R. King
Tech-X, Boulder, Colorado, USA
M. Borland, R. Soliday
ANL, Argonne, Ilinois, USA

Funding: Work supported by the DOE Office of Science, Office of Basic Energy Sciences grant No. DE-SC0004585, and in part by Tech-X Corporation.
Efficient implementation of general-purpose particle tracking on GPUs can result in significant performance benefits to large-scale tracking simulations. This presentation is an update on the current status of our work on accelerating Argonne National Lab’s particle accelerator simulation code ELEGANT using CUDA-enabled GPU. We summarize the performance of beamline elements ported to GPU, and discuss optimization techniques for some important collective effects kernels, in particular our methods of avoiding costly thread contention. We also present preliminary results of a scaling study of the GPU-accelerated version of the code.

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MOPME037

The Development of Stochastic Processes in COSY Infinity

457

J.D. Kunz
IIT, Chicago, Illinois, USA
M. Berz, K. Makino
MSU, East Lansing, Michigan, USA
P. Snopok
Illinois Institute of Technology, Chicago, Illlinois, USA

Funding: Work supported by U.S. Department of Energy.
COSY Infinity is an arbitrary-order beam dynamics simulation code. It can determine high-order transfer maps of combinations of particle optical elements. New features are being developed for inclusion in COSY to follow the distribution of particles through matter. To study in detail the properties of muons passing through material, the transfer map approach alone is not sufficient. The interplay of beam optics and atomic processes must be studied by a hybrid transfer map–Monte-Carlo approach in which transfer map methods describe the average behavior of the particles including energy loss, and Monte-Carlo methods are used to provide small corrections to the predictions of the transfer map accounting for the stochastic nature of scattering and straggling of particles. The advantage of the new approach is that the vast majority of the dynamics is represented by fast application of the high-order transfer map of an entire element and accumulated stochastic effects. The gains in speed will aid the optimization of muon cooling channels. Progress on the development of the required algorithms is reported.

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MOPME038

Space Charge Simulation in COSY using The Fast Multipole Method

460

B.T. Loseth, M. Berz, K. Makino
MSU, East Lansing, Michigan, USA
P. Snopok
Fermilab, Batavia, Illinois, USA
H. Zhang
JLab, Newport News, Virginia, USA

A method is implemented in COSY Infinity that allows the computation of space charge effects of arbitrary and large distributions of particles in an efficient and accurate way based on a variant of the Fast Multipole Method (FMM). It relies on an automatic multigrid-based decomposition of charges in near and far regions and the use of high-order differential algebra methods to obtain decompositions of far fields that lead to an error that scales with a high power of the order. Given an ensemble of N particles, the method allows the computation of the self-fields of all particles on each other with a computational expense that scales as O(N). Furthermore, the method allows the computation of all high-order multipoles of the space charge fields that are necessary for the computation of high-order transfer maps and all resulting aberrations. Space charge effects are crucial in modeling the latter stages of the six-dimensional (6D) cooling channel for the Muon Collider. Results of simulating the 6D cooling channel for the Muon Collider using the FMM method and other tools and improvements implemented for ionization cooling lattices are presented.

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MOPME040

MadFLUKA Beam Line 3D Builder. Simulation of Beam Loss Propagation in Accelerators

463

M. Santana-Leitner, Y. Nosochkov, T.O. Raubenheimer
SLAC, Menlo Park, California, USA

Funding: This work was supported by Department of Energy contract DE-AC02-76-SFO0515
Beam tracking programs provide information of orbits along the nominal trajectory to design beam-line optics. Other aspects like machine or radiation protection, which inspect the transverse dimensions and volumes, are simulated with radiation transport Monte Carlo codes, some of which also include magnetic tracking capabilities. Evaluation of certain aspects, like beam loss shower induced propagation along a beam line, or beam mis-steering phase-space, would require to combine features of both types of codes, or use the latter ones with full accelerator 3D implementations, often too cumbersome and time consuming. This paper presents MadFLUKA, a program that produces FLUKA compatible geometries from MAD files. Objects selected from a user user-configurable database are auto-replicated with the rules of ‘twiss’ and ‘survey’ files to create beam lines with hundreds of components. FLUKA magnetic subroutine is generated from MAD optics, including history randomization of fields for ray-trace analysis of mis-steering failures. MadFLUKA is used in the design of the LCLS-II, at SLAC.

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MOPME043

Modeling and Simulation of Beam-induced Plasma in Muon Cooling Devices

466

K. Yu
SBU, Stony Brook, USA
M. Chung, A.V. Tollestrup, K. Yonehara
Fermilab, Batavia, Illinois, USA
B.T. Freemire
IIT, Chicago, Illinois, USA
V. Samulyak
BNL, Upton, Long Island, New York, USA
V. Samulyak
SUNY SB, Stony Brook, New York, USA

Understanding of the interaction of muon beams with plasma in muon cooling devices is important for the optimization of the muon cooling process. We have developed numerical algorithms and parallel software for self-consistent simulation of the plasma production and its interaction with particle beams and external fields. Simulations support the experimental program on the hydrogen gas filled RF cavities in the Mucool Test Area (MTA) at Fermilab. Computational algorithms are based on the electromagnetic particle-in-cell (PIC) code SPACE combined with a probabilistic, macroparticle-based implementation of atomic physics processes such as the absorption of the incident particles, ionization of the absorber material, and the generation and evolution of secondary particles in dense, neutral gas. In particular, we have proposed a novel algorithm for dealing with repetitive incident beam, enabling simulations of long time scale processes. Benchmarks and simulations of the experiments on gas-filled RF cavities and prediction for future experiments are discussed.
* kwangmin.yu@stonybrook.edu
** rosamu@bnl.gov

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MOPRI069

Computing Angularly-resolved Far Field Emission Spectra in Particle-in-cell Codes using GPUs

761

R.G. Pausch, H. Burau, M.H. Bussmann, J.P. Couperus, A.D. Debus, A. Huebl, A. Irman, A. Köhler, U. Schramm, K. Steiniger, R. Widera
Helmholtz-Zentrum Dresden-Rossendorf (HZDR), Institute of Radiation Physics, Dresden, Germany
T.E. Cowan
HZDR, Dresden, Germany

Angularly resolved far field radiation spectra computed from the Lienard Wiechert Potentials of accelerated electrons give information on the microscopic particle dynamics. We present recent results using our many-GPU, fully relativistic 3D3V particle-in-cell code PIConGPU for which we have developed fully synthetic radiation diagnostics that is capable of computing angularly-resolved radiation spectra of more than 10¹⁰ electrons for several hundred to a thousand wavelengths and directions in a single simulation in less than a day on large-scale supercomputers. With such a technique it is possible to use precision spectroscopic methods for understanding the dynamics of electron acceleration in scenarios where other diagnostics fail. We present studies on laser-driven wakefield acceleration and astrophysical jet dynamics to underline the power of this new technique.

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TUXB01

Recent Progress in 3D Numerical Wakefield Calculations

944

W. Bruns
WBFB, Berlin, Germany

The 3D electromagnetic Field Simulator GdfidL computes Wakepotentials on standard CPUs with a Speed comparable to GPU-Based Implementations. This is achieved via Computing only in interesting Cells, having the FD-Coefficients in compressed Form, traversing the Grid in a Cache-friendly Order and applying a blocked Update Scheme which is NuMA-aware. A Dispersion optimised Scheme is described. Fields in dispersive Materials are computed via solving the Equations of the Electron Hulls of the Material. Moving Mesh Computations have the Grid-generation on the Fly.

Slides TUXB01 [16.169 MB]

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TUOAB01

Computation of Eigenmodes in Long and Complex Accelerating Structures by Means of Concatenation Strategies

947

T. Flisgen, J. Heller, U. van Rienen
Rostock University, Faculty of Computer Science and Electrical Engineering, Rostock, Germany

Funding: This research was partially funded by the EuCARD project which is co-funded by European Commission 7th in Framework Programme (FP7).
The computation of eigenmodes for complex accelerating structures is a challenging and important task for the design and operation of particle accelerators. Discretizing long and complex structures to determine its eigenmodes leads to demanding computations typically performed on super computers. This contribution presents an application example of a method to compute eigenmodes and other parameters derived from these eigenmodes for long and complex structures using standard workstation computers. This is accomplished by the decomposition of the complex structure into several single segments. In a next step, the electromagnetic properties of the segments are described in terms of a compact state space model. Subsequently, the state space models of the single structures are concatenated to the full structure. The results of direct calculations are compared with results obtained by the concatenation scheme in terms of computational time and accuracy.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-TUOAB01

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