10 Controls and Simulation
Paper Title Page
MOAAI2
 Latest Developments in 3D Charged Particle Simulations  
 
  • M.C. Balk, F. Wolfheimer
    CST, Darmstadt, Germany
  
  In the last decades the usage of simulation tools has helped not only to reduce prototype costs but also to improve the understanding of modern electronic devices. Simulation is especially critical for charged particle applications since the complexity of the electromagnetic field calculation is further compounded by the need to take charged particle motion into account. All necessary technology for such a simulation is available in CST STUDIO SUITE under the same interface: A static solver for magnet and electrode design, transient and eigenmode solver for the resonator analysis, PIC and wakefield solver for the simulation of charged particle dynamics and a thermal solver to take heating effects due to material losses or particle impact into account. In parallel to an increasing acceptance of simulation tools, also the expectations have increased. Nowadays, the possibility of simulation is not sufficient and the performance is a key issue. Thus, high performance computing options such as MPI and GPU computing are implemented. In this paper recent developments will be presented, starting from an explanation of the method and demonstrated by various application examples.  
slides icon Slides MOAAI2 [3.869 MB]  
 
MOSBI1 Automatic Computer Algorithms for Beam-based Setup of the LHC Collimators 15
 
  • G. Valentino, N.J. Sammut
    University of Malta, Information and Communication Technology, Msida, Malta
  • R.W. Aßmann, R. Bruce, S. Redaelli, B. Salvachua, D. Wollmann
    CERN, Geneva, Switzerland
  
  Funding: FP7 EuCARD - WP8 ColMat
Beam-based setup of the LHC collimators is necessary to establish the beam centers and beam sizes at the collimator locations and determine the operational settings during various stages of the LHC machine cycle. Automatic software algorithms have been successful in reducing the costly beam time required for the alignment, as well as significantly reducing human error. In this paper, the beam-based alignment procedure is described, and the design of algorithms such as a BLM feedback loop, parallel collimator alignment, pattern recognition of BLM loss spikes, automatic loss threshold selection and coarse BPM-interpolation guided alignment is explained. A comparison on the alignment results from the 2010 to the 2012 LHC runs is presented to illustrate the improvements achieved with the automatic algorithms. 		 
slides icon Slides MOSBI1 [10.572 MB]  
 
MOSBC2 Linac Beam Dynamics Simulations with PyORBIT 20
 
  • A.P. Shishlo
    ORNL, Oak Ridge, Tennessee, USA
  
  Funding: ORNL/SNS is managed by UT-Battelle, LLC, for the U.S. Department of Energy under Contract No. DE-AC05-00OR22725
Linac dynamics simulation capabilities of the PyORBIT code are discussed. The PyORBIT is an open source and a further development of the original ORBIT code that was developed and used for design, studies, and commissioning of the SNS ring. The PyORBIT code like the original one has a two layers structure. The C++ is used to perform time consuming computations, and a program flow is controlled from the Python language shell. The flexible structure allowed using the PyORBIT also for linac dynamics simulations. The benchmark of the PyORBIT with Parmila and the XAL Online model is presented. 		 
slides icon Slides MOSBC2 [1.857 MB]  
 
MOSBC3 An Implementation of the Virtual Accelerator in the Tango Control System 23
 
  • P.P. Goryl, A.I. Wawrzyniak
    Solaris, Kraków, Poland
  • M. Sjöström
    MAX-lab, Lund, Sweden
  • T. Szymocha
    Cyfronet, Kraków, Poland
  
  Funding: Work supported by the European Regional Development Fund within the frame of the Innovative Economy Operational Program: POIG.02.01.00-12-213/09
Integration of simulating codes into the control system gives a possibility to improve machine operation. Providing tools for making computations directly within the control system and letting exchange data between the control system and models is a way of simplifying the whole process of calculating and applying machine's operational parameters as well as keeping track of them. In addition, having so-called an on-line model could be useful for system diagnostic and faults detection, especially when the objective approach is considered. The concept of the Virtual Accelerator will be presented as well as its implementation for the Tango control system as it is planned to be used for both facilities: the Solaris in Kraków, Poland and the MAX IV in Lund, Sweden. This includes the ModelServer tango device, the simplified C/C++ Tango API to be used with codes like Tracy and the tango2elegant script providing easy solution for integrating the Elegant tool with the Tango. 		 
slides icon Slides MOSBC3 [2.232 MB]  
 
WEAAC2 Simulation of Baseband BTFs Using a Particle-in-cell Code 121
 
  • P.A. Görgen
    TEMF, TU Darmstadt, Darmstadt, Germany
  • O. Boine-Frankenheim
    GSI, Darmstadt, Germany
  • W. Fischer, S.M. White
    BNL, Upton, Long Island, New York, USA
  
  A simulation model for transverse bunched beam transfer functions (BTFs) at the base harmonic is presented. It is based on a code including different machine effects, most notably transverse space charge using a two-dimensional (2D) Poisson solver. A simplified model for the simulation of the strong-strong beam-beam effect was implemented using either 2D field data or analytic expressions under the assumption of Gaussian beams for the beam-beam interaction. The validity of the BTF model is verified based on the comparison of BTF and Schottky spectra features with analytic expectations from literature. The simulation model is then applied to the RHIC proton lattice. A linear transfer map is used between interaction points. BTFs including the beam-beam effect are simulated. Measurements are compared to simulation results at machine conditions.  
slides icon Slides WEAAC2 [2.829 MB]  
 
WEAAC3 Dynamics of Ferrite Cavities and their Effect on Longitudinal Dipole Oscillations 124
 
  • C. Spies, M. Glesner
    TUD, Darmstadt, Germany
  • U.K. Hartel, H. Klingbeil
    TEMF, TU Darmstadt, Darmstadt, Germany
  • H.G. König
    GSI, Darmstadt, Germany
  
  Funding: This work is supported by the German Federal Ministry of Education and Research under grant number 06DA9028I.
In a synchrotron, particles are accelerated by repeatedly passing through RF cavities. In the SIS18 synchrotron at GSI, ferrite cavities are used. Each cavity is equipped with local control systems to adjust the amplitude and phase of the accelerating field. In this paper, we consider ferrite cavities of the type that is currently used in the SIS18 at GSI and will be used in the future SIS100 which is being built in the frame of the FAIR project. We analyze the dynamics of the cavities in conjunction with their local control loops. An emphasis is put on the cavities' reaction to changes in the desired amplitude or resonant frequency. Using simulations, we show that the cavities' dynamics hardly influence longitudinal dipole oscillations, and conclude that a high-level model for the RF cavities is sufficient. 		 
slides icon Slides WEAAC3 [1.055 MB]  
 
WEAAC4 Design of a Computer Based Resonator-Simulator for Tests of RF Control Systems 127
 
  • T. Bahlo, C. Burandt, R. Eichhorn, J. Enders, M. Konrad, P.N. Nonn
    TU Darmstadt, Darmstadt, Germany
  
  Funding: supported by the BMBF contract 06DA9024I
In order to test RF control systems for accelerator cavities without being dependent on available prototypes, a resonator-simulator has been developed. The Simulator is based on a Xilinx-VIRTEX-4 FPGA-module and has been configured using MATLAB-Simulink with a special Xilinx-Blockset. The underlying model for this configuration is a parallel RLC-circuit that has been parameterised with common RF-quantities like the resonance frequency, driving frequency, bandwidth and quality factor. This approach allows to simulate the behaviour of normal conducting cavities with quality factors up to 104 as well as superconducting cavities with quality factors up to 109. Besides, it can as well be operated in a continuous-wave as in a pulsed mode. We report on the mathematical model, its digital representation and on the benchmarking against real cavity behaviour. 		 
slides icon Slides WEAAC4 [2.540 MB]  
 
WEACI1 Design and Applications of the Bmad Library for the Simulation of Particle Beams and X-Rays 179
 
  • D. Sagan
    CLASSE, Ithaca, New York, USA
  
  The Bmad software library has been developed for simulations of high-energy particle beams along with simulations of the x-rays produced by the particle beams. Owing to its modular, object-oriented design, Bmad is now used in a number of programs at Cornell's Laboratory for Elementary-Particle Physics. This paper will discuss the design of the Bmad library. Features such as the ability to have overlapping elements, the ability to define in a lattice file the action of control-room ‘‘knobs'', and the ability to choose from a number of different tracking options on an element-by-element basis have all contributed to a versatile simulation environment that eases the task of programmers and users using Bmad. Also discussed is the uses that Bmad has been put to including synchrotron radiation tracking with reflections from the vacuum chamber walls, spin tracking, beam break-up instability, intra-beam scattering, etc. Besides simulation and design programs, Bmad can be used in control programs to do such things as orbit and Twiss correction calculations.  
slides icon Slides WEACI1 [1.884 MB]  
 
THP12
 Computation of an Uniform Irradiation Method for the Vertical Proton Beam using Chi-square fitting and 2D Target Stage  
 
  • Y.S. Park, S.J. Cho, G. Hahn, H.B. Hong, I.S. Jung, J. Kang, T.K. Yang
    KIRAMS, Seoul, Republic of Korea
  
  Funding: Ministry of Educational Science and Technology(MEST)
There are several methods to implement uniform irradiation on the wide target area for accelerated ion beam. Usually, the methods can be divided into two categories, in terms of physical perspective and algorithmic one. Moving beam or target itself belong to the former, while scanning algorithm like spot, raster, and line, belongs to the latter. In this work, we computed an uniform irradiation method for the vertical proton beam using chi-square fitting and XY target stage. The reasons why we select the target movement method instead of the beam itself are that there was not enough space to install the large magnet for modification of accelerated beam path within gantry system of MC-50 cyclotron, and also it was impossible to modify the structure of the gantry system itself. Beam scanning algorithms, spot, raster, and line scan, were applied to the motion control program of the target stage after carrying out a computer simulation using chi-square fitting for obtaining the optimal solution under the required conditions. We performed experiment at vertical beam-line of the MC-50 cyclotron gantry in KIRAMS and compared the experimental result with the simulated one. 		 
 
THP13 Emission Studies of Photocathode RF Gun at PITZ 242
 
  • J. Li, G. Asova, M. Groß, L. Hakobyan, I.I. Isaev, Ye. Ivanisenko, M. Khojoyan, G. Klemz, G. Kourkafas, M. Krasilnikov, K. Kusoljariyakul, M. Mahgoub, D. Malyutin, B. Marchetti, A. Oppelt, B. Petrosyan, S. Rimjaem, A. Shapovalov, F. Stephan, G. Vashchenko
    DESY Zeuthen, Zeuthen, Germany
  • G. Feng
    DESY, Hamburg, Germany
  • D. Richter
    HZB, Berlin, Germany
  • L. Shang
    USTC/NSRL, Hefei, Anhui, People's Republic of China
  
  The Photo Injector Test facility at DESY, Zeuthen site (PITZ), was built to develop and optimize electron sources for linac based Free Electron Lasers(FELs) like FLASH and the European XFEL. For the value of the bunch charge extracted from a photocathode, discrepancy has been observed between the data measured at PITZ and simulation results from the ASTRA code. As a factor which could explain the discrepancy, a Schottky-like effect is considered. Meanwhile, the Parmela code was applied to the emission studies on the PITZ gun as benchmark. Since Parmela cannot be used to simulate a Schottky-like effect with its own modules, MATLAB scripts have been developed to implement this feature of the photoemission in an RF gun.  
 
FRSAI3 PIC Simulations of Laser Ion Acceleration via TNSA 290
 
  • L. Lecz
    TEMF, TU Darmstadt, Darmstadt, Germany
  • O. Boine-Frankenheim, V. Kornilov
    GSI, Darmstadt, Germany
  
  The laser acceleration of protons via the TNSA (Target Normal Sheath Acceleration) mechanism from a thin metal foil (few micrometer) interacting with intense and short (several 100 fs) laser pulse is investigated by using 1D and 2D particle-in-cell electro-magnetic VORPAL [1] simulations. The protons originate from the very thin hydrogen-rich contamination layer on the target rear surface. In the 1D view we have found that two models well describe the longitudinal acceleration in the two extreme cases: quasi-static acceleration [2] for mono-layers and isothermal plasma expansion [3] for thick layers. The grid heating, which is the most important issue in 2D simulations, and its effect on the proton acceleration is discussed. The required numerical parameters and boundary conditions for stable and reliable 2D simulations are also presented.
[1] http://www.txcorp.com/products/VORPAL/
[2] M. Passoni et al., Phys Rev E 69, 026411 (2004)
[3] P. Mora, Phys. Rev. Lett., 90, 185002 (2003) 		 
slides icon Slides FRSAI3 [4.325 MB]  
 
FRABI1 Independent Component Analysis (ICA) Applied to Long Bunch Beams in the Los Alamos Proton Storage Ring 294
 
  • J.S. Kolski, R.J. Macek, R.C. McCrady, X. Pang
    LANL, Los Alamos, New Mexico, USA
  
  Independent component analysis (ICA) is a powerful blind source separation (BSS) method. Compared to the typical BSS method, principal component analysis (PCA), which is the BSS foundation of the well known model independent analysis (MIA), ICA is more robust to noise, coupling, and nonlinearity. ICA of turn-by-turn beam position data has been used to measure the transverse betatron phase and amplitude functions, dispersion function, linear coupling, sextupole strength, and nonlinear beam dynamics. We apply ICA in a new way to slices along the bunch, discuss the source signals identified as betatron motion and longitudinal beam structure, and for betatron motion, compare the results of ICA and PCA.  
slides icon Slides FRABI1 [8.062 MB]