ICAP 2006 - List of Keywords (controls)

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Paper	Title	Other Keywords	Page
MOM1MP01	Massive Tracking on Heterogeneous Platforms	simulation, dynamic-aperture, collider, hadron	13
	E. McIntosh, F. Schmidt CERN, Geneva F. de Dinechin ENS LYON, Lyon
	The LHC@home project uses public resource computing to simulate circulating protons in the future Large Hadron Collider (LHC). As the physics simulated may become chaotic, checking the integrity of the computation distributed over a heterogeneous network requires perfectly identical (or homogeneous) floating-point behaviour, regardless of the model of computer used. This article defines an acceptable homogeneous behaviour based on existing standards, and explains how to obtain it. This involves processor, operating system, programming language and compiler issues. In the LHC@home project, imposing this homogeneous behaviour entailed less than 10% performance degradation per processor, and almost doubled the number of processors which could be usefully exploited.
	Slides

MOAPMP01	Coupled Transient Thermal and Electromagnetic Finite Element Simulation of Quench in Superconducting Magnets	simulation, superconducting-magnet, electromagnetic-fields, target	70
	C. W. Trowbridge, J. Simkin, S. Taylor, E. Xu Vector Fields Ltd., Oxford
	Resistive, normal zones may propagate through the low temperature superconducting coils. The rise in temperature in the windings and the internal voltages developed during this quench process are a critical issue for magnet safety, in addition the eddy currents induced in support structures during a quench may result in large Lorentz forces that can cause damage. Approximate adiabatic models have been used to achieve good results for the time profile of the current decay. More accurate methods based on finite element simulations have also been used to obtain temperature and voltage distributions. This paper describes transient, closely coupled thermal, electromagnetic finite element and circuit simulations developed to model quenching magnets. The program was designed to be efficient for this calculation. It uses nodal finite elements for the transient thermal simulation and edge elements for the electromagnetic simulation. The two simulations can be performed on different symmetry groups so that the model size can be minimized. Circuit models are coupled to the electromagnetic simulator either using filamentary edge loops or with a full volume mesh in the coils. Accurately meshing the coils increases the model size, but it is essential if accurate fields and time derivatives of the field are required. The main source of heat in the coils during quench is resistive loss in the normal zone. However rate dependent losses caused by the changing magnetic field may cause heating and therefore trigger a quench in other coils. Having closely coupled thermal and electromagnetic simulations makes it easy to include these effects and hence greatly improves the reliability of the simulation. Calculated and measured results for a 4 coil superconducting polarized target magnet will be presented. In this system the quench spreads to another coil as a result of rate dependent losses, the calculated results change dramatically if these losses are not included. M. N. Wilson, Superconducting magnets p217ff ** S. Caspi et Al, Calculating Quench propagation with Ansys, IEEE Trans. Appl. Supperconduct. Vol 13, No2, pp1714-1717
	Slides

MOAPMP03	Geometrical Methods in Computational Electromagnetism	simulation, background	75
	A. Bossavit LGEP, Gif-sur-Yvette
	From almost one century, it has been known that vector fields E, H, D, B, etc., in the Maxwell equations are just "proxies" for more fundamental objects, the differential forms e, h, d, b, etc., that when integrated on lines or surfaces, as the case may be, yield physically meaningful quantities such as emf's, mmf's, fluxes, etc. This viewpoint helps separate the "non-metric" part of the equations (Faraday and Ampère), fully covariant, from the "metric" one (the constitutive laws), with more restricted (Lorentz) covariance. The usefulness of this viewpoint in computational issues has been realized more recently, and will be the main topic addressed in this survey. It makes the association of degrees of freedom with mesh elements such as edges, facets, etc. (instead of nodes as in traditioanl finite element techniques), look natural, whereas the very notion of "edge element" seemed exotic twenty years ago. It explains why all numerical schemes treat Faraday and Ampère the same way, and only differ in the manner they discretize metric-dependent features, i.e., constitutive laws. What finite elements, finite volumes, and finite differences, have in common, is thus clearly seen. Moreover, this seems to be the right way to advance the "mimetic discretization" or "discrete differential calculus" research programs, which many dream about: a kind of functorial transformation of the partial differential equations of physics into discrete models, when space-time continuum is replaced by a discrete structure such as a lattice, a simplicial complex, etc. Though total fulfillment of this dream is still ahead, we already have something that engineers –especially programmers keen on object-oriented methods– should find valuable: A discretization toolkit, offering ready-to-use, natural "discrete" counterparts to virtually all "continuous" objects discernible in the equations, fields, differential operators, v x B force fields, Maxwell tensor, etc.
	Slides

TUPPP05	A Space Charge Algorithm for the Bunches of Elliptical Cross Section with Arbitrary Beam Size and Particle Distribution	space-charge, beam-losses, linac, antiproton	106
	A. Orzhekhovskaya, G. Franchetti GSI, Darmstadt
	Algorithms of analytical and semi-analytical calculation of the electric field for the bunches of variable elliptical cross section are proposed. An arbitrary space charge distribution is fitted on the interval of consideration by the polynom of optimal order. In the case of an axisymmetric 3D ellipsoidal bunch or an arbitrary 2D elliptic cross section of the bunch the analytic solution is derived. For the bunch of variable elliptical cross section proposed method is developed to a numerical method using longitudinal grid. Tests of the field computation show high accuracy of the calculations and good agreement of the algorithms with the general theory. The methods are applied to the space charge modeling for the GSI project "Facility for Antiproton and Ion Research at Darmstadt" (FAIR), where particle loss must be calculated during long term storage, and to the code benchmarking in frame of the project "High Intensity Pulsed Proton Injector" (HIPPI).

TUPPP14	The TileCal DCS Detector Control System	monitoring, power-supply, hadron, laser	118
	J. Pina, A. Gomes, C. N. Marques LIP, Lisboa C. Alexa, G. Arabidze CERN, Geneva M. Ouchrif Université Blaise Pascal, Clermont-Ferrand A. Zenin IHEP Protvino, Protvino, Moscow Region
	TileCal is the barrel hadronic calorimeter of the ATLAS detector. The main task of the TileCal Detector Control System (DCS) is to enable the coherent and safe operation of the detector. All actions initiated by the operator and all errors, warnings and alarms concerning the hardware of the detector are handled by DCS. TileCal DCS design is being finalized, prototypes of most of the systems were already produced, and some components were already produced and installed in the detector. The low voltage control system is composed by several components with monitoring and control mostly based on the ATLAS developped ELMB boards. The high voltage system is based on the HV-micro boards developed by TileCal. A DCS system covering a small sector of the TileCal barrel was assembled and is already working in the ATLAS cavern, and by October we expect to have already a full partition equipped with low voltage, high voltage and cooling system.

TUPPP23	Numerical Minimization of Longitudinal Emittance in Linac Structures	emittance, linac, target, acceleration	124
	S. Lange, M. Clemens, L. O. Fichte Helmut-Schmidt-University, Hamburg M. Dohlus, T. Limberg DESY, Hamburg
	Relativistic electron bunches in linear colliders are characterized by 6D phase spaces. In most linear accelerators, the longitudinal phase space distribution does not interact significantly with the transverse distributions. This assumption allows the use of a 2D design model of the longitudinal phase space. The design of linear colliders is typically based on manipulations in the longitudinal phase space. The two dimensional single bunch tracking code LiTrack (Bane/Emma 2005) allows to simulate bunch-compression up to 3rd order and RF acceleration with wake fields. This code is implemented in Matlab with a graphic user interface front end. In order to improve the ability to simulate a two-stage bunch compression system, which consist of a RF accelerating section, a higher harmonic RF section and a dipole magnet chicane, an extension to the LiTrack code is proposed. An analytical model of this two-stage bunch compression system is defined using the energy and the momentum derivatives up to 3rd order of the system. As a consequence, the energy of the system can now be specified directly, for the simulation criteria the peak current and the symmetry of the charge distributions and be specified via parameters. This extended model allows the definition of bunches with an arbitrary energy, phase space correlation, longitudinal emittance, charge distribution and resulting peak current. A minimal longitudinal emittance is generally considered as a quality factor of the bunch, where the bunch energy, peak current and a symmetric charge distribution are represented as constraints. Under these conditions, a constrained optimization problem is defined to minimize the longitudinal emittance with a predetermined bunch-energy and peak-current with respect to the charge distribution symmetry. For the solution of this problem, LiTrack is extended with a optimization solver based on a SQP formulation to find an optimal bunch corresponding to the newly introduced constraints.

WEPPP12	New Developments of MAD-X UsingPTC	lattice, closed-orbit, linac, quadrupole	209
	P. K. Skowronski, F. Schmidt, R. de Maria CERN, Geneva E. Forest KEK, Ibaraki
	For the last few years the MAD-X program makes use of the Polymorphic Tracking Code (PTC) to perform calculations related to beam dynamics in the nonlinear regime. This solution has provided an powerful tool with a friendly and comfortable user interface. Its apparent success has generated a demand for further extensions. We present the newest features developed to fulfill in particular the needs of the Compact LInear Collider (CLIC) studies. A traveling wave cavity element has been implemented that enables simulations of accelerating lines. An important new feature is the extension of the matching module to allow fitting of non-linear parameters to any order. Moreover, calculations can be performed with parameter dependence defined in the MAD-X input. In addition the user can access the PTC routines for the placement of a magnet with arbitrary position and orientation. This facilitates the design of non-standard lattices. Lastly, for the three dimensional visualization of lattices, tracked rays in global coordinates and beam envelopes are now available.

WEPPP14	Advances in Matching with MAD-X.	dipole, sextupole, insertion, quadrupole	213
	R. de Maria, F. Schmidt, P. K. Skowronski CERN, Geneva
	A new matching algorithm and a new matching mode have been developped for MadX in order to increase its potentialities. The new algorithm (JACOBIAN) is able to solve a generalized matching problem with an arbitrary number of variables and constraints, aiming to solve the corresponding least square problem. The new mode (USE\_MACRO) allows the user to construct his own macros and expressions for the definition of the constraints. The new algorithm and the new mode where succesfully used for finding optic transitions, tunability charts and non-linear chromaticity correction. They can be used as a general tool for solving inverse problems which can be defined in MadX using all the available modules (twiss, ptc,track, survey, aperture, etc).

WESEPP01	CST's Commercial Beam-Physics Codes	simulation, emittance, impedance, electromagnetic-fields	228
	U. Becker CST, Darmstadt
	During the past decades Particle Accelerators have grown to higher and higher complexity and cost, so that a careful analysis and understanding of the machines' behaviour becomes more and more important. CST offers userfriendly numerical simulation tools for the accurate analysis of electromagnetic fields in combination with charged particles, including basic thermal analysis. The CST STUDIO SUITE code family is the direct successor of the code MAFIA, combining the numerical accuracy of the Finite Integration Theory and Perfect Boundary Approximation within an intuitive, easy-to-use CAD environment. Automatic Parameter Sweeping and Optimization are available to achieve and control the design goals. In this paper various solver modules of CST PARTICLE STUDIO, CST EM STUDIO and CST MICROWAVE STUDIO will be presented along accelerator-relevant examples, such as: Cavity design using eigenmode solver including calculation of losses, Q-factors, shunt impedance and thermal analysis. Coupler Design, including external Q-factor Wakefield Simulation, including resistive wall effects, also realized for beams slower than speed of light dispersion diagram for the analysis of periodic structures design of guns, including beam emittance studies study of secondary emission processes and dark current effects in accelerating structures.

WEA2IS01	Status and Future Developments in Large Accelerator Control Systems	collider, site, linear-collider, diagnostics	239
	K. S. White Jefferson Lab, Newport News, Virginia
	Funding: This work was supported by DOE contract DE-AC05-06OR23177, under which Jefferson Science Associates, LLC operates Jefferson Lab. Over the years, accelerator control systems have evolved from small hardwired systems to complex computer controlled systems with many types of graphical user interfaces and electronic data processing. Today’s control systems often include multiple software layers, hundreds of distributed processors, and hundreds of thousands of lines of code. While it is clear that the next generation of accelerators will require much bigger control systems, they will also need better systems. Advances in technology will be needed to ensure the network bandwidth and CPU power can provide reasonable update rates and support the requisite timing systems. Beyond the scaling problem, next generation systems face additional challenges due to growing cyber security threats and the likelihood that some degree of remote development and operation will be required. With a large number of components, the need for high reliability increases and commercial solutions can play a key role towards this goal. Future control systems will operate more complex machines and need to present a well integrated, interoperable set of tools with a high degree of automation. Consistency of data presentation and exception handling will contribute to efficient operations. From the development perspective, engineers will need to provide integrated data management in the beginning of the project and build adaptive software components around a central data repository. This will make the system maintainable and ensure consistency throughout the inevitable changes during the machine lifetime. Additionally, such a large project will require professional project management and disciplined use of well-defined engineering processes. Distributed project teams will make the use of standards, formal requirements and design and configuration control vital. Success in building the control system of the future may hinge on how well we integrate commercial components and learn from best practices used in other industries.
	Slides

WEA2IS02	Beam Control and Monitoring with FPGA-Based Electronics: Status and Perspectives	monitoring, damping, instrumentation	245
	N. E. Eddy Fermilab, Batavia, Illinois
	Modern FPGAs support designs using roughly 10⁶ logic gates, pipeline speeds exceeding 200 MHz, internal SRAM, dedicated multipliers for signal processing, clock generation using phase-locked loops, and a variety of single-ended and differential I/O standards, including fast serial links. When interfaced with high-speed ADCs, DACs, and other components commonly found in telecom applications, FPGAs facilitate a wide range of beam control and monitoring applications. Examples include beam-position measurement, low-level RF control, instability damping, and manipulation of accelerator timing signals. Once signals of interest are in digital form, an instrument's FPGA logic and memory provide a natural means to capture data for remote diagnosis–both of beam behavior and of the instrument itself. Finally, FPGA-based solutions provide a flexible, reconfigurable, and reusable toolkit for instrumentation: existing modules are often adapted to implement new applications, and useful code fragments can be quickly copied from design to design.
	Slides

WEA2IS03	The Fermilab Accelerator Control System	collider, target, antiproton, instrumentation	246
	J. F. Patrick Fermilab, Batavia, Illinois
	The Fermilab accelerator complex supports simultaneous operation of 8 and 120 GeV fixed target lines, a high intensity neutrino source (NUMI), antiproton production, and a 1.8 TeV proton-antiproton collider. Controlling all this is a single system known as ACNET. ACNET is based on a three tier architecture featuring a high degree of scalability, large scale parallel data logging, security, accountability, a states facility, a sequencer for automated operation. In recent years the system has been enhanced to support the demands of the current run, and also modified to reduce dependence in the upper layers on the obsolete VAX/VMS platform. A Java based infrastruture has been developed, and is now used for most middle layer functionality as well as some applications. A port of most of the remaining VMS code to Linux is nearing completion. This migration has been accomplished with minimal interruption to operations.
	Slides

THM2IS01	Accelerator Description Formats	lattice, simulation, background, quadrupole	297
	N. Malitsky BNL, Upton, Long Island, New York R. M. Talman CLASSE, Ithaca, New York
	Being an integral part of accelerator software, accelerator description aims to provide an external representation of an accelerator’s internal model and associative effects. As a result, the choice of description formats is driven by the scope of accelerator applications and is usually implemented as a tradeoff between various requirements: completeness and extensibility, user and developer orientation, and others. Moreover, an optimal solution does not remain static but instead evolves with new project tasks and computer technologies. This talk presents an overview of several approaches, the evolution of accelerator description formats, and a comparison with similar efforts in the neighboring high-energy physics domain. Following the UAL Accelerator-Algorithm-Probe pattern, we will conclude with a next logical specification, Accelerator Propagator Description Format (APDF), providing a flexible approach for associating physical elements and evolution algorithms most appropriate for the immediate tasks.
	Slides

THM2IS02	The Universal Accelerator Parser	lattice, linac, quadrupole, sextupole	303
	D. Sagan Cornell University, Department of Physics, Ithaca, New York D. A. Bates LBNL, Berkeley, California A. Wolski Liverpool University, Science Faculty, Liverpool
	The Universal Accelerator Parser (UAP) is a library for reading and translating between lattice input formats. The UAP was primarily implemented to allow programs to parse Acelerator Markup Language (AML) formatted files [D. Sagan et al. ‘‘The Accelerator Markup Language and the Universal Accelerator Parser'', 2006 Europ. Part. Acc. Conf.]. Currently, the UAP also supports the MAD lattice format. The UAP provides an extensible framework for reading and translating between different lattice formats. Included are routines for expression evaluation and beam line expansion. The use of a common library among accelerator codes will greatly improve the interoperability between different lattice file formats, and ease the development and maintenance to support these formats in programs. The UAP is written in C++ and compiles on most Unix, Linux, and Windows platforms. A Java port is maintained for platform independence. Software developers can easily integrate the library into existing code by using the provided hooks.
	Slides

THM2IS03	CST's Commercial Beam-Physics Codes	simulation, emittance, impedance, electromagnetic-fields	308
	U. Becker CST, Darmstadt
	During the past decades Particle Accelerators have grown to higher and higher complexity and cost, so that a careful analysis and understanding of the machines' behaviour becomes more and more important. CST offers userfriendly numerical simulation tools for the accurate analysis of electromagnetic fields in combination with charged particles, including basic thermal analysis. The CST STUDIO SUITE code family is the direct successor of the code MAFIA, combining the numerical accuracy of the Finite Integration Theory and Perfect Boundary Approximation within an intuitive, easy-to-use CAD environment. Automatic Parameter Sweeping and Optimization are available to achieve and control the design goals. In this paper various solver modules of CST PARTICLE STUDIO, CST EM STUDIO and CST MICROWAVE STUDIO will be presented along accelerator-relevant examples, such as: Cavity design using eigenmode solver including calculation of losses, Q-factors, shunt impedance and thermal analysis. Coupler Design, including external Q-factor Wakefield Simulation, including resistive wall effects, also realized for beams slower than speed of light dispersion diagram for the analysis of periodic structures design of guns, including beam emittance studies study of secondary emission processes and dark current effects in accelerating structures.
	Slides