EPAC 2006 - Classification:05 Beam Dynamics and Electromagnetic Fields/D05 Code Developments and Simulation Techniques

05 Beam Dynamics and Electromagnetic Fields

D05 Code Developments and Simulation Techniques

Paper	Title	Page
WEYFI01	Modelling of Space Charge and CSR Effects in Bunch Compressor Systems	1897
	M. Dohlus DESY, Hamburg
	Bunches with high peak currents of the order of kilo-Amperes are required in linac based X-ray free electron lasers. These bunches cannot be produced directly in guns because space charge forces would destroy the brilliance within a short distance. Therefore bunches with a peak current of a few tens of Amperes are created in laser-driven radio-frequency sources and are compressed in length by two orders of magnitude. In most designs, the compression is achieved in magnet chicanes, where particles with different energies have different path lengths so that a bunch with an energy distribution correlated with longitudinal particle position can shrink in length. The principle problem is that short bunches on curved trajectories will emit coherent synchrotron radiation (CSR). The CSR effects and the space charge fields play an important role in the particle dynamic and the design of a bunch compression system. This presentation will provide an overview of computational methods and simulation tools for space charge and coherent synchrotron radiation effects in magnetic bunch compression systems.
	Transparencies
WEOFI03	Beam Dynamics Simulation in e^- Rings in SRFF Regime	1908
	L. Falbo INFN-Pisa, Pisa D. Alesini INFN/LNF, Frascati (Roma) M. Migliorati Rome University La Sapienza, Roma
	The concept of strong RF focusing has been recently proposed to obtain locally short bunches in electron/positron colliders, by modulating the longitudinal bunch dimensions along the rings. To study the single bunch dynamics, a macroparticle numerical code has been written which simulates the effects of the objects generating broad band impedance along the ring and the effects of the coherent synchrotron radiation in dipoles and wigglers. The obtained results are shown and discussed.
	Transparencies
WEPCH106	Stationary Beam Electron Transport in AIRIX for the TRAJENV Code	2161
	O. Mouton CEA, Bruyères-le-Châtel
	In the framework of the AIRIX program, the electron beam propagation between the injector and the X-conversion target is routinely simulated with the 2D TRAJENV code. We describe the physical models implemented in the code for a intense stationary beam. We present both the modeling of applied electromagnetic forces in induction cells and self generated ones. To avoid the cell damage due to target debris generated by the electron beam impact, a thin debris shield has been tested upstream the X-ray converter. Such a thin foil located in the beam pass, is taken into account in TRAJENV. We describe the modeling and the influence of the foil on the beam.
WEPCH107	Contributors to AIRIX Focal Spot Size	2164
	N. Pichoff, M. Caron, F. Cartier, D.C. Collignon, A. Compant La Fontaine, G. Grandpierre, L.H. Hourdin, M. Mouillet, D.P. Paradis CEA, Bruyères-le-Châtel
	High intensity electron beam focusing is a key issue for the successful development of flash radiography at hydro test facilities. AIRIX is a 2 kA, 19 MeV, 60 ns, single shot linear accelerator that produces X-rays from the interaction between relativistic electrons and a Tantalum solid target (Ta). A simulation tool has been developed to model the pulsed-beam dynamics through the accelerator from the cathode to the target. This simulator has allowed to estimate the contribution to the beam size on the target (focal spot) of beam emittance, pulse energy dispersion, pulse rising and falling fronts and the ion production on the target. The quantified contributions of these phenomena are reviewed here.
WEPCH109	Comprehensive Benchmark of Electromagnetic 3D Codes in Time and Frequency Domain	2167
	V. Serriere, N. Guillotin, J. Jacob ESRF, Grenoble F. Marhauser, E. Weihreter BESSY GmbH, Berlin
	A comprehensive benchmark of todays most powerful numerical 3D Eigenmode and Time Domain Solvers has been performed using the input geometry of a HOM-damped cavity and a highly lossy waveguide load developed at BESSY. The paper details the simulations results together with existing experimental data.
WEPCH110	Calculation of Wake Potentials in General 3D Structures	2170
	H. Henke TET, Berlin W. Bruns CERN, Geneva
	The wake potential is defined as an integration along an axis of a structure. It includes the infinitely long beam pipe regions and in case of numerical evaluation leads to pipe wake artefacts. If the structure is cavity like one can position the integration path on the pipe wall and only the integration over the cavity gap remains. In case of axis-symmetric protruding structures it was proposed by O. Napoly et al. to deform the path such that the integration in the pipe regions is again on the wall. The present paper generalizes this method of path deformation to 3D structures with incoming and outgoing beam pipes. Its usefulness is verified with the code GdfidL and no artifacts were observed.
WEPCH111	Time Domain Radiation of a Gaussian Charge Sheet Passing a Slit in a Conducting Screen	2173
	M. Filtz, H. Henke TET, Berlin
	A semi-analytical method is proposed to calculate in time-domain the radiation of a relativistic Gaussian charge sheet travelling parallel to a slotted conducting screen. The method is based on transient line current elements as basis functions which have a triangular time dependence. Making use of duality magnetic current elements are used in the slot region. Radiation fields are shown and the transverse kick received by a test charge is given. The dual problem, the scattering of the fields at a conducting strip, is also treated. The main purpose of the paper is to present an effective algorithm which is easy to implement for computing and visualising plane scattering and diffraction problems in time domain.
WEPCH112	Database Extension for the Beam Dynamics Simulation Tool V-code	2176
	W. Ackermann, W.F.O. Müller, B. Steiner, T. Weiland TEMF, Darmstadt J. Enders, H.-D. Gräf, A. Richter TU Darmstadt, Darmstadt
	The beam dynamics simulation tool V-Code has been proved to be very useful in redesigning the injector layout at the superconducting linear accelerator in Darmstadt (S-DALINAC). Modifications in the beam optics are necessary because a new source of polarized electrons should be installed in addition to the existing thermionic gun. The calculations are performed with V-Code which is designed to handle a large amount of individual beam line elements and can therefore be used for extensive accelerator studies. The available database includes all the necessary components like solenoids, quadrupoles and rf cavities, but as a result of their consecutive treatment overlapping external fields are not allowed. Due to geometrical restrictions in the assembly of the new source a space-saving candidate of a quadrupole triplet violates this software-related condition if it is regarded as three distinct quadrupoles. Consequently, a more general beam line element has to be created which treats the lenses as a single unit without interference of their fields to attached cells. The indispensable data base extension together with simulation results and implementation verifications will be presented.
WEPCH113	Numerical Impedance Calculations for the GSI SIS-100/300 Kickers	2179
	B. Doliwa, H. De Gersem, T. Weiland TEMF, Darmstadt
	Fast kicker modules represent a potential source for beam instabilities in the planned Facility for Antiproton and Ion Research (FAIR) at the Gesellschaft für Schwerionenforschung (GSI), Darmstadt. In particular, the more than fifty kicker modules to be installed in the SIS-100 and SIS-300 synchrotrons are expected to have a considerable parasitic influence on the high-current beam dynamics. Here we present our numerical investigations of the longitudinal and transverse kicker coupling impedances using a specialized electromagnetic field software. Besides the coupling to the external network, particular attention is paid to the question whether a resistively-coated ceramic beam pipe is able to reduce coupling impedances and ferrite heating significantly.
WEPCH114	On the Development of a Self-consistent Particle-in-cell (PIC) Code Using a Time-adaptive Mesh Technique	2182
	S. Schnepp, E. Gjonaj, T. Weiland TEMF, Darmstadt
	For a large class of problems the self-consistent simulation of charged particle beams in linear accelerators is necessary. Especially, in all low-energetic sections such as injectors the self-consistent interaction of particles and fields has to be taken into account. Well-known programs like the MAFIA TS Modules typically use the Particle-in-cell (PIC) method for beam dynamics simulations. Since they use a fixed computational grid which has to resolve the bunch adequately, they suffer from enormous memory consumption. Therefore and especially in the 3D case, only rather short sections can be simulated. A remedy to this limitation is the usage of a grid which refines itself in the vicinity of particles. For this purpose, a new code called SMOVE based on a time-adaptive grid is being developed. First promising results will be presented at the conference.
WEPCH115	Numerical Simulation and Optimization of a 3-GHz Chopper/Prebuncher System for the S-DALINAC	2185
	N. Somjit, W.F.O. Müller, T. Weiland TEMF, Darmstadt R. Eichhorn, J. Enders, H.-D. Gräf, C. Heßler, Y. Poltoratska, A. Richter TU Darmstadt, Darmstadt
	A new source of polarized electrons with an energy of 100 keV is presently being developed at the superconducting Darmstadt electron linear accelerator S-DALINAC for future nuclear- and radiation-physics experiments. The pulsed electron beam emitted by the photocathode will be cut to 50 ps by a chopper operated at 3 GHz, and further bunch compression down to 5 ps will be achieved by a two-stage prebuncher section. The chopper-prebuncher system is based on similar devices used at the Mainz Mikrotron (MAMI) where the accelerator frequency is slightly smaller (2.4 GHz). For the chopper, a cylindrical resonator operating at TM110 mode is selected to deflect the electron beam onto an ellipse, i.e., both horizontally and vertically. This is simply achieved by particular slits on both ends of the resonator. The prebunching system consists of two cavities. For increasing the longitudinal capture efficiency, the first cavity will be operated at the fundamental accelerator frequency of the S-DALINAC of 3 GHz, and the second cavity at 6 GHz. The cavities are designed to work at the TM010 mode and TM020 mode for the fundamental and first harmonic, respectively.
WEPCH116	Recent Simulation Results of the Polarized Electron Injector (SPIN) of the S-DALINAC	2188
	B. Steiner, W.F.O. Müller, T. Weiland TEMF, Darmstadt J. Enders, H.-D. Gräf, C. Heßler, G. Iancu, A. Richter, M. Roth TU Darmstadt, Darmstadt
	Recent design and development for a polarized electron source (SPIN) for the recirculating superconducting electron linear accelerator S-DALINAC will be presented. The polarized electron beam will be produced by photoemission from an InAlGaAs/GaAs superlattice cathode and will be accelerated to 100 kV electrostatically. The results of the beam dynamics simulation will be shown in detail. The start phase space of the electron bunch behind the gun has been approximated. The transverse focusing system consists of very short quadrupoles. Further main components of the new injector are a Wien filter, a Mott polarimeter, a chopper-prebuncher system (based on devices used at the Mainz Mikrotron MAMI), and diverse beam diagnostic tools. For the approximation of the start phase space CST MAFIA is used, and for the beam dynamic simulation VCode is used.
WEPCH117	Beam Dynamics of an Integrated RFQ-drifttube-combination	2191
	A. Bechtold, M. Otto, A. Schempp IAP, Frankfurt-am-Main
	In the frame of a collaboration with the GSI in Darmstadt an RFQ-Drifttube-Combination for the Heidelberg cancer therapy center HICAT has been designed, built and successfully beam tested at the IAP Frankfurt. The integration and combination of both an RFQ and a rebunching drifttube unit inside a common cavity forming one single resonant RF-structure has been realized for the first time with this machine. The results of the beam measurements and questions about the beam dynamics simulations of such a combination have been investigated in detail with the code RFQSIM.
WEPCH118	LORASR Code Development	2194
	R. Tiede, G. Clemente, H. Podlech, U. Ratzinger, A.C. Sauer IAP, Frankfurt-am-Main S. Minaev ITEP, Moscow
	LORASR is specialized on the beam dynamics design of Separate Function DTL's based on the 'Combined 0 Degree Structure (KONUS)' beam dynamics concept. The code has been used for the beam dynamics design of several linacs already in operation (GSI-HLI, GSI-HSI, CERN Linac 3, TRIUMF ISAC-I) or scheduled for the near future (Heidelberg Therapy Injector, GSI Proton Linac). Recent code development was focused on the implementation of a new PIC 3D FFT space charge routine, facilitating time-efficient simulations with up to 1 million macro particles routinely, as well as of tools for error study and loss profile investigations. The LORASR code was successfully validated within the European HIPPI Project activities: It is the Poisson solver benchmarking and the GSI UNILAC Alvarez section tracking comparison programme. The error study tools are a stringent necessity for the design of future high intensity linacs. The new LORASR release will have a strong impact on the design of the GSI FAIR Facility Proton Linac, as well as the transmission investigations on the IFMIF Accelerator. This paper presents the status of the LORASR code development and the benchmarking results.
WEPCH119	Beam Performance with Internal Targets in the High-energy Storage Ring (HESR)	2197
	A. Lehrach, R. Maier, D. Prasuhn FZJ, Jülich O. Boine-Frankenheim, R.W. Hasse GSI, Darmstadt F. Hinterberger Universität Bonn, Helmholtz-Institut für Strahlen- und Kernphysik, Bonn
	The High-energy Storage Ring of the future International Facility for Antiproton and Ion Research (FAIR) at GSI in Darmstadt is planned as an antiproton synchrotron storage ring in the momentum range of 1.5 to 15 GeV/c. An important feature of HESR is the combination of phase space cooled beams and dense internal targets (e.g., pellet targets), which results in demanding beam parameter requirements for two operation modes: high luminosity mode with peak luminosities of up to 2·10³² cm-2 s-1, and high resolution mode with a momentum spread down to 10-5, respectively. The beam cooling equilibrium and beam loss with internal target interaction is analyzed. Rate equations are used to predict the rms equilibrium beam parameters. The cooling and intra-beam scattering rate coefficients are obtained from simplified models. Energy loss straggling in the target and the associated beam loss are analyzed analytically assuming a thin target. A longitudinal kinetic simulation code is used to study the evolution of the momentum distribution in coasting and bunched beam. The analytic expressions for the target induced momentum tail are found in good agreement with the simulation results. *A. Lehrach et al. Beam Performance and Luminosity Limitations in the High-Energy Storage Ring (HESR), Nuclear Inst. and Methods in Physics Research, A44704 (2006).
WEPCH120	Simulation of 3D Space-charge Fields of Bunches in a Beam Pipe of Elliptical Shape	2200
	A. Markovik, G. Pöplau, U. van Rienen Rostock University, Faculty of Computer Science and Electrical Engineering, Rostock K. Floettmann DESY, Hamburg
	Recent applications in accelerator design require precise 3D calculations of space-charge fields of bunches of charged particles additionally taking into account the shape of the beam pipe. An actual problem of this kind is the simulation of e-clouds in damping rings. In this paper a simulation tool for 3D space-charge fields is presented where a beam pipe with an arbitrary elliptical shape is assumed. The discretization of the Poisson equation by the method of finite differences on a Cartesian grid is performed having the space charge field solved only in the points inside the elliptical cross-section of the beam pipe taking care of the conducting boundaries of the pipe. The new routine will be implemented in the tracking code ASTRA. Numerical examples demonstrate the performance of the solution strategy underling the new routine. Further tracking results with the new method are compared to established space-charge algorithms such as the FFT-approach.
WEPCH121	3D Space-charge Calculations for Bunches in the Tracking Code ASTRA	2203
	G. Pöplau, U. van Rienen Rostock University, Faculty of Computer Science and Electrical Engineering, Rostock K. Floettmann DESY, Hamburg
	Precise and fast 3D space-charge calculations for bunches of charged particles are of growing importance in recent accelerator designs. One of the possible approaches is the particle-mesh method computing the potential of the bunch in the rest frame by means of Poisson's equation. In that, the charge of the particles are distributed on a mesh. Fast methods for solving Poisson's equation are the direct solution applying Fast Fourier Methods (FFT) and a finite difference discretization combined with a multigrid method for solving the resulting linear system of equations. Both approaches have been implemented in the tracking code ASTRA. In this paper the properties of these two algorithms are discussed. Numerical examples will demonstrate the advantages and disadvantages of each method, respectively.
WEPCH122	2D Wake Field Calculations of Tapered Structures with Different FDTD Discretization Schemes	2206
	C. Schmidt Rostock University, Institute for General Electrical Engn., Rostock H.-W. Glock, U. van Rienen Rostock University, Faculty of Engineering, Rostock
	The continual performance improvement of particle accelerators requires advanced prediction of parasitic wake field effects, even in structures of comparatively weak influence like tapers. In the case of smooth tapered components, even well established codes like MAFIA* demonstrate strong discretization dependency of the results or solver instabilities, making them not reliable in such applications. Grid dispersion is assumed to generate this failure. In Ref.** an alternative discretization scheme is described, using a homogeneous rotated mesh intended to eliminate such grid dispersion effects. In order to study the dependence on the discretization applied, we use this scheme to calculate wake fields in prototype taper structures of rotational symmetry. Furthermore a comparison is provided with the results of a non-rotated mesh, MAFIA runs and - so far applicable - analytical approaches. MAFIA V4.107: CST GmbH, Bad Nauheimer Str. 19, D-64289 Darmstadt*R. Hampel et al. New discretization scheme for wake field computation in cylindrically symmetric structure. Proc. EPAC'04, pp 2559
WEPCH123	Large Simulation of High Order Short Range Wakefields	2209
	A. Bungau Cockcroft Institute, Warrington, Cheshire R.J. Barlow UMAN, Manchester
	We present a formalism for incorporating intra-bunch wake fields into particle-by-particle tracking codes, such as MERLIN and BDSIM. Higher order wake field effects are incorporated in a manner which is computationally efficient. Standard formulae for geometric, resistive and dielectric wake fields are included for various apertures, particularly those relevant for ILC collimators. Numerous examples are given.
WEPCH124	BDSIM - Beamline Simulation Toolkit Based on Geant4	2212
	I.V. Agapov, G.A. Blair, J. Carter Royal Holloway, University of London, Surrey O. Dadoun LAL, Orsay
	BDSIM is a code that combines accelerator-style particle tracking with traditional Geant-style tracking based on Runge-Kutta techniques. This approach means that particle beams can be tracked efficiently when inside the beampipe, while also enabling full Geant4 processes when beam-particles interact with beamline apertures. Tracking of the resulting secondary particles is automatic. The code is described, including a new MAD-style interface and new geometry description, and key performance parameters are listed.
WEPCH125	New Design Tools for a Cyclotron Central Region	2215
	D. Battaglia, L. Calabretta, D. Campo, M.M. Maggiore, L.A.C. Piazza, D. Rifuggiato INFN/LNS, Catania
	A code that allows us to design the spiral inflector and the central region of the SCENT cyclotron was implemented. The code integrates the main equations of motion of a particle in an electromagnetic field and provides an useful interface to describe the geometry and the physical constraints of the inflector and the central region to be simulated. The mechanical drawings of the inflector and the central region is made using a standard CAD. These drawings are then imported in OPERA 3D to produce the maps of the electric and magnetic field. An application interface allows us to enter the emittance and the particles’ distributions to be transported through the inflector. An iterative process to design the central region was also developed and tested.
WEPCH126	Issues in Modelling of Negative Ion Extraction	2218
	M. Cavenago INFN/LNL, Legnaro, Padova V. Antoni, F. Sattin CNR/RFX, Padova
	In the context of negative ion sources proposed for neutral beam injectors for tokamaks, halo of the extracted beam is typically large (about 10 %) and optimum shape of the multiaperture extraction electrode is a matter of research. Present designs range from an aperture angle of 45 degree (low current, convergent beam) to 90 degrees (flat electrode, high current, large divergence and halo). Two major difficulties of the beam extraction modelling are here discussed. First, the generation processes of negative ion show some shortcomings: volume production seems low; wall production is large, but ions have wrong directions and/or large nonuniformity in current density; elastic scattering of wall generated ions into the extraction direction must compete with mutual neutralization. Second, the plasma sheath charge has to be negative on the extraction hole surface and positive on the nearby wall surface, which enhances beam aberration near hole edge. After discussing limitation of existing codes and model, result from an ad hoc code are discussed. Also 2D equation for the selfconsistent electrostatic field can be written and implemented into a multiphysics general purpose program.
WEPCH127	Analysis of Radiative Effects in the Electron Emission from the Photocathode and in the Acceleration inside the RF Cavity of a Photoinjector using the 3D Numerical Code RETAR	2221
	V. Petrillo, C. Maroli Universita' degli Studi di Milano, Milano G. Alberti Università degli Studi di Milano, Milano A. Bacci, A.R. Rossi, L. Serafini INFN-Milano, Milano M. Ferrario INFN/LNF, Frascati (Roma)
	The three-dimensional fully relativistic and self-consistent code RETAR has been developed to model the dynamics of high-brightness electron beams and in particular to assess the importance of the retarded radiative part of the emitted electromagnetic fields in all conditions where the electrons experience strong accelerations. In this analysis we evaluate the radiative energy losses in the electron emission process from the photocathode of an injector, during the successive acceleration of the electron beam in the RF cavity and the focalization due to the magnetic field of the solenoid, taking also into account the e.m. field of the laser illuminating the cathode. The analysis is specifically carried out with parameters of importance in the framework of the SPARC and PLASMONX projects.
WEPCH128	Virtual Accelerator as an Operation Tool at J-PARC 3 GeV Rapid Cycling Synchrotron (RCS)	2224
	H. Harada, K. Shigaki Hiroshima University, Higashi-Hiroshima K. Furukawa KEK, Ibaraki H. Hotchi, F. Noda, H. Sako, H. Suzuki JAEA/J-PARC, Tokai-Mura, Naka-Gun, Ibaraki-Ken S. Machida CCLRC/RAL/ASTeC, Chilton, Didcot, Oxon
	We developed a virtual accelerator based on EPICS for 3 GeV Rapid-Cycle Synchrotron (RCS) in J-PARC. It is important to have an on-line model of optics parameters, such as tunes, Twiss parameters, dispersion function, at the commissioning stage in a high intensity proton machine. It gives a strong feedback for the RCS operation as a commissioning tool as well as for the studies of beam dynamics issues. Beam position monitors with finite resolutions, a transverse exciter to measure the betatron frequency, and a RF system with variable frequency to simulate off-momentum optics have been implemented into the system. The virtual accelerator system itself and some results of beam dynamics studies will be presented.
WEPCH130	Analysis of Symmetry in Accelerating Structures with Group Theory	2227
	S. Sakanaka KEK, Ibaraki
	Many rf cavities for modern accelerators have a variety of symmetry. There is a question as to what is the connection between the symmetry of a cavity and of its eigenmodes. This can be clarified* using the representation theory of groups. The geometric symmetry of a cavity can be expressed by a group of symmetry operations. The structure of this group can be represented by a set of matrices called representation. The group is associated with several irreducible representations which can express possible patterns of transformations under the symmetry operations. The irreducible representations are very suitable to express the symmetry of each eigenmode. This method can be used to improve the understanding of non-axially symmetric structures. In this paper, this method is first explained, and then, it is extended to the application of symmetric periodic structures. *S. Sakanaka, Phys. Rev. ST Accel. Beams 8, 072002 (2005).
WEPCH131	Development of Numerical Code for Self-consistent Wake Field Analysis with Curved Trajectory Electron Bunches	2230
	H. Kawaguchi Muroran Institute of Technology, Department of Electrical and Electronic Engineering, Muroran K. Fujita Hokkaido University, Sapporo
	Strongly interacting phenomena of electromagnetic radiation fields and ultra-relativistic electron is one of great interests in accelerator science such as in electron beam dynamics at the bunch compressor. The phenomena are described by time domain boundary value problem for the Lienard-Wiechert solutions. Authors develop a time domain boundary element method for self-consistent wake fields analysis of electromagnetic fields and charged particles. To use boundary integral equation for describing the electromagnetic fields, the time domain boundary value problems for the Lienard-Wiechert solution can be naturally formulated and we can simulate the wake fields phenomena with electron beam dynamics. In this paper, beam dynamics of curved trajectory electron bunches inside uniform beam tube are numerically simulated by using 2.5 dimension time domain boundary element technique. Various effects of closed beam tube for ultra-relativistic electron dynamics are considered comparing with the Lienard-Wiechert solutions in free space.
WEPCH132	Design Study of Dedicated Computer System for Wake Field Analysis with Time Domain Boundary Element Method	2233
	K. Fujita, T. Enoto Hokkaido University, Sapporo H. Kawaguchi Muroran Institute of Technology, Department of Electrical and Electronic Engineering, Muroran
	Time domain boundary element method (TDBEM) has advantages of dispersion free calculations and modeling of curved beam trajectories in wake field analysis compared to conventional methods. These advantages give us powerful possibilities for analysis of beam dynamics due to CSR in bunch compressors of next-generation accelerators. On the other hand, the TDBEM also has a serious difficulty of large computational costs. In this paper, a dedicated computer system for wake field analysis with the TDBEM is proposed as one of solutions for high performance computing (HPC) technologies. Recent remarkable progress of LSI hardware design environments such as HDL compiler tools and large scale FPGAs enables us to make up computer hardware systems with very low cost in a short development period. The authors have been working in design studies of the TDBEM dedicated computer system on such LSI design environments. This paper presents a system design and VHDL simulations of a wake field analysis machine based on the TDBEM.
WEPCH134	Development of Code for Simulation of Acceleration of Ions from Internal Source to End of Extraction System in Cyclotrons and Preliminary Design Study of 8MeV Cyclotron for Production of Radioisotopes	2236
	S.A. Kostromin JINR, Dubna, Moscow Region
	From the users' point of view modern cyclotrons must be compact, energy-saving, low-radiation and very reliable facilities. To provide all these characteristics, a very detailed design study of all systems of an accelerator under development is required. Thus, particle tracking from the "beginning" to the "end" in modern cyclotrons with small gaps in the main acceleration region and with efficient extraction systems becomes a very important task for designers. Codes for beam dynamics simulation at the center, main acceleration region and through the extraction system of the cyclotron have been developed. It is possible to monitor all main beam parameters at the different stages of acceleration, radial, axial and phase motion of the beam and the energy increase. During tracking particles through the extraction system it is possible to calculate rms envelopes of radial and vertical motion of the beam and beam losses at the aperture of the extraction system elements. A preliminary design of a compact 8-MeV proton cyclotron was studied using created codes. The accelerator is supposed to have a four sector compact magnet system with the pole 64 cm in diameter.
WEPCH136	Monte Carlo Simulation Model of Internal Pellet Targets	2239
	O.A. Bezshyyko, K.A. Bezshyyko, I.M. Kadenko, R.V. Yermolenko National Taras Shevchenko University of Kyiv, The Faculty of Physics, Kyiv A. Dolinskii NASU/INR, Kiev V.G. Ziemann UU/ISV, Uppsala
	We develop a numerical model of a pellet target and use it for Monte Carlo simulations of the interaction of a circulating beam with a pellet target. Real geometry details of the pellet beam and the beam are taken into account. We emphasize the role of tails of non-Gaussian distributions for transverse scattering and energy loss. These effects are especially important for simultaneous calculations of electron cooling, intrabeam scattering and target influence. Black-box algorithms for the generation of automatic nonuniform random variate distributions are used for the effective time averaging of scattering angle and energy loss distributions.
WEPCH137	FAKTOR2: A Code to Simulate the Collective Effects of Electrons and Ions	2242
	W. Bruns, D. Schulte, F. Zimmermann CERN, Geneva
	A new code for computing the multiple effects of slowly moving charges is being developed. The basic method is electrostatic particle in cell. The underlying grid is rectangular and locally homogeneous. At regions of interest, e.g., where the beam is, or near material boundaries, the mesh is refined recursively. The motion of the macroparticles is integrated with an adapted timestep. Fast particles are treated with a smaller timestep, and particles in regions of fine grids are also treated with a fine timestep. The position of collision of particles with material boundaries is accurately resolved. Secondary particles are then created according to user-specified yield functions.
WEPCH138	Simulations of Long-range Beam-beam Interaction and Wire Compensation with BBTRACK	2245
	U. Dorda, F. Zimmermann CERN, Geneva
	We present weak-strong simulation results for the effect of long-range beam-beam collisions in LHC, SPS, RHIC and DAFNE, as well as for proposed wire compensation schemes or wire experiments, respectively. In particular, we discuss details of the simulation model, instability indicators, the effectiveness of compensation, the difference between nominal and PACMAN bunches for the LHC, beam experiments, and wire tolerances. The simulations are performed with the new code BBTRACK.
WEPCH139	WISE: An Adaptative Simulation of the LHC Optics	2248
	P. Hagen, M. Giovannozzi, J.-P. Koutchouk, T. Risselada, S. Sanfilippo, E. Todesco, E.Y. Wildner CERN, Geneva
	The LHC beam dynamics requires a tight control of the magnet field quality and geometry. As the production of the magnets advances, decisions have to be made on the acceptance of possible imperfections. To ease decision making, an adaptative model of the LHC optics has been built, based on the current information available (e.g. magnetic measurements at warm or cold, magnet allocation to machine slots) as well as on statistical evaluations for the missing information (e.g. magnets yet to be built, measured, or for non-allocated slots). The uncertainties are included: relative and absolute measurement errors, warm-to-cold correlations for the fraction of magnets not measured at cold, hysteresis and power supply accuracy. A pre-processor generates instances of the LHC ring for the MADX program, with the possibility of selecting various error sources. A post-processor computes ranges for relevant beam optics parameters and distributions. This approach has been applied to the expected beta-beating, to the possible impact of permeability issues in some quadrupole collars, to the geometrical displacements of the multipolar correctors and to prioritize the magnetic measurement programme.
WEPCH140	Recent Improvements of PLACET	2251
	A. Latina, H. Burkhardt, L. Neukermans, G. Rumolo, D. Schulte, R. Tomas CERN, Geneva P. Eliasson Uppsala University, Uppsala J. Resta-López IFIC, Valencia
	The tracking code PLACET is used to simulate the beam transport in linear colliders from the damping ring to the interaction point and beyond. Recent improvements of the code are presented. They include the possibility to simulate bunch compressors and to use parallel computer systems.
WEPCH141	Accelerator Physics Code Web Repository	2254
	F. Zimmermann, R. Basset, E. Benedetto, U. Dorda, M. Giovannozzi, Y. Papaphilippou, T. Pieloni, F. Ruggiero, G. Rumolo, F. Schmidt, E. Todesco CERN, Geneva D.T. Abell Tech-X, Boulder, Colorado R. Bartolini Diamond, Oxfordshire O. Boine-Frankenheim, G. Franchetti, I. Hofmann GSI, Darmstadt Y. Cai, M.T.F. Pivi SLAC, Menlo Park, California Y.H. Chin, K. Ohmi, K. Oide KEK, Ibaraki S.M. Cousineau, V.V. Danilov, J.A. Holmes, A.P. Shishlo ORNL, Oak Ridge, Tennessee L. Farvacque ESRF, Grenoble A. Friedman LLNL, Livermore, California M.A. Furman, D.P. Grote, J. Qiang, G.L. Sabbi, P.A. Seidl, J.-L. Vay LBNL, Berkeley, California D. Kaltchev TRIUMF, Vancouver T.C. Katsouleas USC, Los Angeles, California E.-S. Kim PAL, Pohang, Kyungbuk S. Machida CCLRC/RAL/ASTeC, Chilton, Didcot, Oxon J. Payet CEA, Gif-sur-Yvette T. Sen Fermilab, Batavia, Illinois J. Wei BNL, Upton, Long Island, New York B. Zotter Honorary CERN Staff Member, Grand-Saconnex
	In the framework of the CARE HHH European Network, we have developed a web-based dynamic accelerator-physics code repository. We describe the design, structure and contents of this web repository, illustrate its usage, and discuss our future plans.
WEPCH143	Electron Linac Based e,X-radiation Facility	2257
	V.I. Nikiforov, A. Dovbnya, N.A. Dovbnya, V.L. Uvarov NSC/KIPT, Kharkov
	In a number of technologies based on high-current electron accelerators bremsstrahlung is generated in the interaction of the beam with the irradiated object. Thus, in addition to the electron radiation, the bremsstahlung may be used for carring out of different technolodgical programs (e,X-facility). A method for the numerical analysis and optimization of the radiation characteristics of such installation is proposed. The accelerator beam track, starting from the electron source and up to output devices is considered as a single multicomponent target consisting of the layers of different materials. The thickness of each layer is measured in the generalized units of the "stopping length". Using the method of simulation based on the PENELOPE/2001 system the characteristics of the mixed e,gamma-radiation field (energy yield of electrons, photons and their ratio) as function of the stopping length for actual or anticipated version of output equipment can be calculated. To illustrate the method, the parameters of the beam path of the NSC KIPT Linacs used as e,X-facilities was analyzed.
WEPCH144	CSR Effects in a Bunch Compressor: Influence of the Transverse Force and Shielding	2260
	G. Bassi, J.A. Ellison, K.A. Heinemann UNM, Albuquerque, New Mexico
	We study the influence of CSR on particle bunches traveling on arbitrary planar orbits between parallel conducting plates with a fixed "vertical" charge distribution. Our goal is a numerical solution of the 2 degree-of-freedom Vlasov-Maxwell equations. This provides simulations with lower numerical noise than the macroparticle method and allows the study of emittance degradation and microbunching. As reported, we calculate the fields excited by the bunch in the lab frame using a new formula that leads to a simplification. The Vlasov equation is integrated in the beam frame interaction picture using the method of local characteristics. The transformation between traditional beam frame and lab frame coordinates is carefully treated. Here we report on our implementation of the algorithm in the context of a chicane bunch compressor, where the strong correlation between phase space variables requires an adaptive grid. In particular, we present a complete analysis (moments + reduced densities) of the bunch evolution under the fields produced by the unperturbed bunch density. Finally, our progress on the fully self-consistent case is discussed. Vlasov treatment of coherent synchrotron radiation from arbitrary planar orbits, Nucl. Instr. Meth. Phys. Res. A, in press.** ICFA Beam Dynamics Mini-Workshop on CSR, Berlin-Zeuthen, 2002. See http://www.desy.de/csr.
WEPCH145	Particle Tracking and Simulation on the .NET Framework	2263
	H. Nishimura, T. Scarvie LBNL, Berkeley, California
	Particle tracking and simulation studies are becoming complex. In addition to the sophisticated graphics, interactive scripting is becoming popular. A compatibility with the control system requires network and database capabilities. It is not a trivial task to fulfill various requirements without sacrificing the runtime performance. We evaluate the use of .NET to solve this issue by converting a C++ code Goemon* that is an object-oriented version of Tracy developed at ALS. The portability to other platforms will be mentioned in terms of Mono. *H. Nishimura, PAC'01, Chicago, July 2001, p.3066.
WEPCH146	Intrabeam Scattering Studies for the ILC Damping Rings Using a New Matlab Code	2266
	I. Reichel, A. Wolski LBNL, Berkeley, California
	A new code to calculate the effects of intrabeam scattering (IBS)has been developed in Matlab based on the approximation suggested by K. Bane. It interfaces with the Accelerator Toolbox* but can also read in lattice functions from other codes. The code has been benchmarked against results from other codes for the ATF*** that use this approximation or do the calculation in a different way. The new code has been used to calculate the emittance growth due to intrabeam scattering for the lattices currently proposed for the ILC Damping Rings, as IBS is a concern, especially for the electron ring. A description of the code and its user interface, as well as results for the Damping Rings, will be presented. K. Bane, in Proceedings of EPAC2002, p.1443. A. Terebilo, Accelerator Toolbox for MATLAB, SLAC-PUB-8732 and www-ssrl.slac.stanford.edu/at/. **K. Kubo et al. PhysRevST AB.8.081001 (2005).
WEPCH147	Simulations of Electron Effects in Superconducting Cavities with the VORPAL Code	2269
	C. Nieter, J.R. Cary, P. Messmer, D.S. Smithe, P. Stoltz Tech-X, Boulder, Colorado G.R. Werner CIPS, Boulder, Colorado
	Modeling the complex boundaries of superconducting radio frequency (SRF) accelerating cavities on a Cartesian grid is a challenge for many Finite Difference Time Domain (FDTD) electromagnetic PIC codes. The simulation of such cavities require conformal (curve fitting) boundaries. Modeling the full cavity including couplers and ports is fundamentally a three dimensional problem requiring capability to run in parallel on large numbers of processors. We have recently added conformal boundaries using the method of Zagorodnov* to the plasma simulation code VORPAL. Using this higher order boundary algorithm and the surface physics package TxPhysics, we have begun studies of self-consistent electron effects in SRF cavities. We have modeled the beam excitation of cavity modes and the effects of electron multipacting. Results from these studies will be presented using the new user friendly visualization tool that now ships with VORPAL. *I. A. Zagorodnov et al. “A uniformly stable conformal FDTD-method in Cartesian grids,” International Journal of Numerical Modeling 16, 127 (2003).
WEPCH148	Computing TRANSPORT/TURTLE Transfer Matrices from MARYLIE/MAD Lie Maps	2272
	G.H. Gillespie G.H. Gillespie Associates, Inc., Del Mar, California
	Modern optics codes often utilize a Lie algebraic formulation of single particle dynamics. Lie algebra codes such as MARYLIE and MAD offer a number of advantages that makes them particularly suitable for certain applications, such as the study of higher order optics and for particle tracking. Many of the older more traditional optics codes use a matrix formulation of the equations of motion. Matrix codes such as TRANSPORT and TURTLE continue to find useful applications in many areas where the power of the Lie algebra approach is not necessary. Arguably the majority of practical optics applications can be addressed successfully with either Lie algebra or matrix codes, but it is often a tedious exercise to compare results from the two types of codes in any detail. Differences in the choice of dynamic variables, between Lie algebra and matrix codes, compounds the comparison difficulties already inherent in the different formulations of the equations of motion. This paper summarizes key relationships and methods that permit that direct numerical comparison of results from MARYLIE and MAD with those from TRANSPORT and TURTLE.
WEPCH149	PBO LAB (tm) Tools for Comparing MARYLIE/MAD Lie Maps and TRANSPORT/TURTLE Transfer Matrices	2275
	G.H. Gillespie, W. Hill G.H. Gillespie Associates, Inc., Del Mar, California
	Particle optics codes frequently utilize either a Lie algebraic formulation or a matrix formulation of the equations of motion. Examples of codes utilizing the Lie algebra approach include MARYLIE and MAD, whereas TRANSPORT and TURTLE use the matrix formulation. Both types of codes have common application to many particle optics problems. However, it is often a very tedious exercise to compare results from the two types of codes in any great detail. As described in a companion paper in these proceedings, differences in the choice of phase space variables, as well as the inherent differences between the Lie algebraic and matrix formulations, make for unwieldy and complex relations between results from the two types of codes. Computational capabilities have been added to the PBO Lab software that automates the calculation of transfer matrices from Lie maps, and that converts phase space distributions between the different representations used by the codes considered here. Graphical and quantitative comparison tools have been developed for quick and easy visual comparisons of transfer maps and matrices.
WEPCH150	The Accelerator Markup Language and the Universal Accelerator Parser	2278
	D. Sagan, M. Forster Cornell University, Laboratory for Elementary-Particle Physics, Ithaca, New York D.A. Bates, A. Wolski LBNL, Berkeley, California T. Larrieu, Y. Roblin Jefferson Lab, Newport News, Virginia T.A. Pelaia ORNL, Oak Ridge, Tennessee S. Reiche UCLA, Los Angeles, California F. Schmidt CERN, Geneva P. Tenenbaum, M. Woodley SLAC, Menlo Park, California N.J. Walker DESY, Hamburg
	A major obstacle to collaboration on accelerator projects has been the sharing of lattice description files between modeling codes. To address this problem, a lattice description format called Accelerator Markup Language (AML) has been created. AML is based upon the standard eXtensible Markup Language (XML) format; this provides the flexibility for AML to be easily extended to satisfy changing requirements. In conjunction with AML, a software library, called the Universal Accelerator Parser (UAP), is being developed to speed the integration of AML into any program. The UAP is structured to make it relatively straightforward (by giving appropriate specifications) to read and write lattice files in any format. This will allow programs that use the UAP code to read a variety of different file formats. Additionally this will greatly simplify conversion of files from one format to another. Currently, besides AML, the UAP supports the MAD lattice format.
WEPCH152	Comment on Healy's Symplectification Algorithm	2281
	W.W. MacKay BNL, Upton, Long Island, New York
	For long-term tracking, it is important to have symplectic maps for the various electromagnetic elements in an accelerator ring. While many standard elements are handled well by modern tracking programs, new magnet configurations (e.g., a helical dipole with a superimposed solenoid) are being used in real accelerators. Transport matrices and higher terms may be calculated by numerical integration through model-generated or measured field maps. The resulting matrices are most likely not quite symplectic due to numerical errors in the integrators as well as the field maps. In his thesis, Healy presented a simple algorithm to symplectify a matrix. This paper presents a discussion of limitations of this method. L. M. Healy, "Lie Algebraic Methods for Treating Parameter Errors in Particle Accelerators", Doctoral Thesis. University of Maryland, unpublished (1986).
WEPCH153	Symplectic Interpolation	2284
	W.W. MacKay, A.U. Luccio BNL, Upton, Long Island, New York
	It is important to have symplectic maps for the various electromagnetic elements in an accelerator ring. For some tracking problems we must consider elements which evolve during a ramp. Rather than performing a complicated numerical integration for every turn, it should be possible to integrate the trajectory for a few sets of parameters, and then interpolate the transport map as a function of one or more parameters, such as energy. We present two methods for interpolation of symplectic matrices as a function of parameters: one method is based on the logarithm of the matrix, and the other is based on the related but simpler Healy symplectification method.
THXFI01	State of the Art in EM Field Computation	2763
	C.-K. Ng, V. Akcelik, A.E. Candel, S. Chen, N.T. Folwell, L. Ge, A. Guetz, H. Jiang, A.C. Kabel, K. Ko, L. Lee, Z. Li, E.E. Prudencio, G.L. Schussman, R. Uplenchwar, L. Xiao SLAC, Menlo Park, California
	This presentation will provide an up-to-date survey of the methods and tools for the computation of electromagnetic fields in accelerator systems and components.
	Transparencies