Keyword: controls
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MOSBI1 Automatic Computer Algorithms for Beam-based Setup of the LHC Collimators alignment, feedback, injection, collimation 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]  
MOSBC3 An Implementation of the Virtual Accelerator in the Tango Control System lattice, simulation, diagnostics, storage-ring 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]  
MOSDC2 GPGPU Implementation of Matrix Formalism for Beam Dynamics Simulation simulation, target 59
  • N.V. Kulabukhova
    St. Petersburg State University, St. Petersburg, Russia
  Matrix formalism is a map integration method for ODE solving. It allows to present solution of the system as sums and multiplications of 2-indexes numeric matrix. This approach can be easy implement in parallel codes. As the most natural for matrix operation GPU architecture has been choosen. The set of the methods for beam dynamics has been implemented. Particles and envelope dynamics are supported. The computing facilities are located in St. Petersburg State University and presented by the NVIDIA Tesla clusters.  
slides icon Slides MOSDC2 [0.770 MB]  
TUAAI2 A Massively Parallel General Purpose Multi-objective Optimization Framework, Applied to Beam Dynamic Studies simulation, emittance, status, solenoid 62
  • Y. Ineichen, A. Adelmann
    PSI, Villigen, Switzerland
  • P. Arbenz
    ETH, Zurich, Switzerland
  • C. Bekas, A. Curioni
    IBM Research - Zurich, Rueschlikon, Switzerland
  Particle accelerators are invaluable tools for research in basic and applied sciences. The successful design, commissioning, and operation of accelerator facilities is non trivial. We implemented a framework for general simulation-based multi-optimization methods automating the investigation of optimal sets of machine parameters. In order to solve the emerging, huge problems we propose a massively-parallel master/slave approach. We employ the framework to identify optimal parameters of existing and new accelerators at PSI.  
slides icon Slides TUAAI2 [0.694 MB]  
TUSCC2 The Convergence and Accuracy of the Matrix Formalism Approximation 93
  • S.N. Andrianov
    St. Petersburg State University, St. Petersburg, Russia
  Funding: The work is supported by Federal Targeted Program "Scientific and Scientific-Pedagogical Personnel of the Innovative Russia in 2009-2013" (Governmental Contract no. p 793)
To the present time there has been developed a large number of different codes for the particles beam dynamics modeling. However, their precision, accuracy and reliability of the numerical results are not sufficiently guaranteed in the case of long-term evolution of particle beams in circular accelerators. Here we discuss convergence estimates of the matrix presentation for Lie series. We also consider some problems of the matrix formalism accuracy for constructing the evolution operator of the particle beam. In this article there is paid a special attention to problems of symplecticity and energy conservation for long time evolution of particle beams.
slides icon Slides TUSCC2 [1.475 MB]  
WEAAI1 Bringing Large-scale Analytics to Accelerators EPICS, target, monitoring, linac 116
  • N. Malitsky
    BNL, Upton, Long Island, New York, USA
  The report presents a new approach for storing and processing both the accelerator control data and the experimental results. It is based on the analysis and consolidation of several modern technologies, such as the EPICS control infrastructure, the SciDB array-oriented data management and analytics platform, the HDF5 file format, and others. The paper overviews the different features of the proposed system and the development of analytics algorithms in the context of the modern light source facilities.  
slides icon Slides WEAAI1 [2.505 MB]  
WEAAC3 Dynamics of Ferrite Cavities and their Effect on Longitudinal Dipole Oscillations cavity, simulation, resonance, synchrotron 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 cavity, resonance, linac, beam-loading 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]  
WEP06 Particle Tracking in Electrostatic Fields with Energy Conservation simulation, quadrupole, storage-ring, lattice 149
  • A.N. Ivanov
    St. Petersburg State University, St. Petersburg, Russia
  The key idea of the research is to consider spin dynamics in electrostatic fields. Due to the fact, that spin rotation frequency explicitly depends on velocity of the particle and its kinetic energy is changed in electrostatic fields it is important to use some technique that provides both conservation energy and symplicticity condition. An appropriate mathematical model is described and the results of numerical calculation are shown. In conclusion, fringe fields influence is examined and compared with case of ideal fields.  
WEP13 Model-Based Analysis of Digital Signal Processing Blocks in a Beam Phase Control System synchrotron, dipole, ion, heavy-ion 164
  • C. Spies, M. Glesner
    TUD, Darmstadt, Germany
  • H. Klingbeil
    TEMF, TU Darmstadt, Darmstadt, Germany
  Funding: This work is supported by the German Federal Ministry of Education and Research under grant number 06DA9028I.
A beam phase control system comprises digital phase detectors and band pass filters to detect coherent longitudinal dipole and higher order bunch oscillations. These digital signal processing functions can be implemented in several ways, e. g. in software or on a programmable logic device. In this paper, we consider different possible implementations and compare them in terms of their real-time performance and their system resource consumption. For the phase detectors, a software implementation is compared against different (e. g. look-up table and CORDIC-based) hardware implementations. For the band pass filters, we consider software, hardware and mixed implementations.
WEP15 Tools for Analysis and Improvement of Linac Optics Design for High Brightness Electron Beams optics, quadrupole, focusing, emittance 170
  • S. Di Mitri, M. Cornacchia, C. Scafuri
    ELETTRA, Basovizza, Italy
  The optics design of single pass high brightness electron linacs usually aims at the preservation of the transverse emittance. Collective effects mainly impose constraints to the optics design such as at the low-beta interaction points in colliders and magnetic compressors in FELs. Other constraints are from the trajectory correction scheme, performance of diagnostics, collimation systems and physical space limitations. Strong focusing is typically prescribed for all the aforementioned cases, although it may hamper the main goal of emittance preservation through the excitation of optical aberrations. Strong focusing also potentially leads, through focusing errors, to large beam optics mismatch. Based on these sometimes conflicting requirements, we have developed tools for the analysis and improvement of electron linac optics. They are based on the Elegant [1] code and allow the user to identify:
  1. local sources of phase space distortions and emittance dilution,
  2. lattice areas particularly sensitive to focusing errors,
  3. poor trajectory steering.
The analysis does not require massive particle tracking since it deals with the single particle motion in the normalized phase space.

[1] M. Borland, Advanced Photon Source LS-287 (2000).
WEP16 Analytical Presentation of Space Charge Forces space-charge, beam-transport, focusing, optics 173
  • S.N. Andrianov
    St. Petersburg State University, St. Petersburg, Russia
  Funding: The work is supported by Federal Targeted Programme "Scientific and Scientific-Pedagogical Personnel of the Innovative Russia in 2009-2013" (Governmental Contract no. p 793)
This paper presents an analytical description of the space charge forces generated by charged particle beams. The suggested approach is based on some set of models for particle distribution function. All necessary calculations have analytical and closed form for different models for beam density distributions. These model distributions can be used for approximation of real beam distributions. The corresponding solutions are included in a general scheme of beam dynamics presentation based on the matrix formalism for Lie algebraic tools. The corresponding computer software is based on corresponding symbolic codes and some parallel technologies. In particular, as computational tools we consider GPU graphic card NVIDIA. As an example, there is considered the problem of modeling the beam dynamics for microprobe focusing systems.
WEACI1 Design and Applications of the Bmad Library for the Simulation of Particle Beams and X-Rays simulation, lattice, solenoid, quadrupole 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]  
THP02 Beam Dynamics Simulations Using GPUs simulation, ion, linac, synchrotron 227
  • J. Fitzek, S. Appel, O. Boine-Frankenheim
    GSI, Darmstadt, Germany
  PATRIC is a particle tracking code used at GSI to study collective effects in the FAIR synchrotrons. Due to the need for calculation-intense simulations, parallel programming methods are being explored to optimize calculation performance. Presently the tracking part of the code is parallelized using MPI, where each node represents one slice of the particles that travel through the accelerator. In this contribution different strategies will be presented to additionally employ GPUs in PATRIC and exploit their support for data parallelism without major code modifications to the original tracking code. Some consequences of using only single-precision in beam dynamics simulations will be discussed.  
THP06 An OpenMP Parallelisation of Real-time Processing of CERN LHC Beam Position Monitor Data target, insertion, HOM, non-linear-dynamics 230
  • H. Renshall, L. Deniau
    CERN, Geneva, Switzerland
  SUSSIX is a FORTRAN program for the post processing of turn-by-turn Beam Position Monitor (BPM) data, which computes the frequency, amplitude, and phase of tunes and resonant lines to a high degree of precision. For analysis of LHC BPM data a specific version run through a C steering code has been implemented in the CERN Control Centre to run on a server under the Linux operating system but became a real time computational bottleneck preventing truly on-line study of the BPM data. Timing studies showed that the independent processing of each BPMs data was a candidate for parallelization and the OpenMP package with its simple insertion of compiler directives was tried. It proved to be easy to learn and use, problem free and efficient in this case reaching a factor of ten reduction in real-time over twelve cores on a dedicated server. This paper reviews the problem, shows the critical code fragments with their OpenMP directives and the results obtained.  
THSCC2 Reconstruction of Velocity Field electron, space-charge, induction, electromagnetic-fields 256
  • D.A. Ovsyannikov, E.D. Kotina
    St. Petersburg State University, St. Petersburg, Russia
  In this paper we suppose that the distribution density of particles in phase space is known. Using Liouville’s equations the problem of finding velocity field is considered as a minimization problem. Thus the problem of determination of velocity field is reduced to solving of elliptic system of Euler-Lagrange equations.  
slides icon Slides THSCC2 [8.701 MB]