ICAP 2006 - List of Keywords (linac)

A B C D E F G H I K L M O P Q R S T U V W

linac

Paper	Title	Other Keywords	Page
MOMPMP01	Computational Beam Dynamics for SNS Commissioning and Operation	simulation, proton, space-charge, electron	1
	J. A. Holmes, S. M. Cousineau, V. V. Danilov, S. Henderson, D.-O. Jeon, M. A. Plum, A. P. Shishlo, Y. Zhang ORNL, Oak Ridge, Tennessee D. A. Bartkoski UTK, Knoxville, Tennessee
	Funding: SNS is managed by UT-Battelle, LLC, under contract DE-AC05-00OR22725 for the U. S. Department of Energy. The computational approach is providing essential guidance and analysis for the commissioning and operation of SNS. Computational models are becoming sufficiently realistic that it is now possible to study detailed beam dynamics issues quantitatively. Increasingly, we are seeing that the biggest challenge in performing successful analyses is that of knowing and describing the machine and beam state accurately. Even so, successful benchmarks with both theoretical predictions and experimental results are leading to increased confidence in the capability of these models. With this confidence, computer codes are being employed in a predictive manner to guide the machine operations. We will illustrate these points with various examples taken from the SNS linac and ring.
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MOM2IS03	Low-Dispersion Wake Field Calculation Tools	simulation, electromagnetic-fields, vacuum, linear-collider	35
	M. Kärkkäinen, E. Gjonaj, T. Lau, T. Weiland TEMF, Darmstadt
	Funding: This work was partially funded by EUROTeV (RIDS-011899), DFG (1239/22-3) and DESY Hamburg. Extremely short bunches are used in future linear colliders, such as the International Linear Collider (ILC). Accurate and computationally efficient numerical methods are needed to resolve the bunch and to accurately model the geometry. In very long accelerator structures, computational efficiency necessitates the use of a moving window in order to save memory. On the other hand, parallelization is desirable to decrease the simulation times. Explicit schemes are usually more convenient to parallelize than implicit schemes since the implementation of a separate potentially time-consuming linear solver can thus be avoided. Explicit numerical methods without numerical dispersion in the direction of beam propagation are presented for fully 3D wake field simulations and for the special case of axially symmetric structures. The introduced schemes are validated by comparing with analytical results and by providing numerical examples for practical accelerator structures. Conformal techniques to enhance the convergence rate are presented and the advantages of the conformal schemes are verified by numerical examples.
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TUPPP05	A Space Charge Algorithm for the Bunches of Elliptical Cross Section with Arbitrary Beam Size and Particle Distribution	space-charge, beam-losses, controls, 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).

TUPPP23	Numerical Minimization of Longitudinal Emittance in Linac Structures	emittance, controls, 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.

TUPPP30	ROCOCO - A Zero Dispersion Algorithm for Calculating Wake Potentials	simulation, gun, collective-effects, collider	144
	R. Hampel, W. F.O. Müller, T. Weiland TEMF, Darmstadt
	Funding: This work was partially funded by EUROTeV (RIDS-011899) and DESY Hamburg. Wake fields are a limiting factor due to their collective effects. In colliders and high energy accelerators used in FEL projects short bunches excite high frequency fields which make the computation of near range wake fields inaccurate. Additionally the length of modern accelerating structures limit the powers of certain codes such as TBCI or MAFIA. Both limiting factors, i.e. short bunches and length of accelerating structures - a multiscale problem, can be dealt with in the following way. Using certain zero dispersion directions of a usual Cartesian grid leads to a decrease of the overall dispersion which usually arises by having discrete field values. Combined with a conformal modelling technique the full time step limited by the Courant criterion is used and a moving window is applied. Thus simulations of short bunches in long structures are possible - dispersion and memory problems have been avoided. In this work ROCOCO (Rotated mesh and conformal code) is presented. The zero dispersion algorithm uses a new discretization scheme based on a rotated mesh combined with the established USC scheme and the moving window technique mentioned above. The advantage of an explicit algorithm is joined with the zero dispersion along the beam's propagation direction. A dispersion analysis for the 2D version of the code is shown as well as some results for common structures of accelerator physics - such as collimators and the TESLA 9 cell structure.

WEMPMP02	Wish-List for Large-Scale Simulations for Future Radioactive Beam Facilities	simulation, ion, heavy-ion, diagnostics	170
	J. A. Nolen ANL, Argonne, Illinois
	Funding: This work is supported by the U. S. Department of Energy under contract W-31-109-Eng-38. As accelerator facilities become more complex and demanding and computational capabilities become ever more powerful, there is the opportunity to develop and apply very large-scale simulations to dramatically increase the speed and effectiveness of many aspects of the design, commissioning, and finally the operational stages of future projects. Next-generation radioactive beam facilities are particularly demanding and stand to benefit greatly from large-scale, integrated simulations of essentially all aspects or components. These demands stem from things like the increased complexity of the facilities that will involve, for example, multiple-charge-state heavy ion acceleration, stringent limits on beam halos and losses from high power beams, thermal problems due to high power densities in targets and beam dumps, and radiological issues associated with component activation and radiation damage. Currently, many of the simulations that are necessary for design optimization are done by different codes, and even separate physics groups, so that the process proceeds iteratively for the different aspects. There is a strong need, for example, to couple the beam dynamics simulation codes with the radiological and shielding codes so that an integrated picture of their interactions emerges seamlessly and trouble spots in the design are identified easily. This integration is especially important in magnetic devices such as heavy ion fragment separators that are subject to radiation and thermal damage. For complex, high-power accelerators there is also the need to fully integrate the control system and beam diagnostics devices to a real-time beam dynamics simulation to keep the tunes optimized without the need for continuous operator feedback. This will most likely require on-line peta-scale computer simulations. The ultimate goal is to optimize performance while increasing the cost-effectiveness and efficiency of both the design and operational stages of future facilities.
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WEPPP01	Recent Developments in IMPACT and Application to Future Light Sources	simulation, electron, lattice, space-charge	182
	I. V. Pogorelov, J. Qiang, R. D. Ryne, M. Venturini, A. Zholents LBNL, Berkeley, California R. L. Warnock SLAC, Menlo Park, California
	The Integrated Map and Particle Accelerator Tracking (IMPACT) code suite was originally developed to model beam dynamics in ion linear accelerators. It has been greatly enhanced and now includes a linac design code, a 3D rms envelope code and two parallel particle-in-cell (PIC) codes IMPACT-T, a time-based code, and IMPACT-Z, a z-coordinate based code. Presently, the code suite has been increasingly used in simulations of high brightness electron beams for future light sources. These simulations, performed using up to 100 million macroparticles, include effects related to nonlinear magnetic optics, rf structure wake fields, 3D self-consistent space charge, and coherent synchrotron radiation (at present a 1D model). Illustrations of application for a simulation of the microbunching instability are given. We conclude with plans of further developments pertinent to future light sources.

WEPPP02	Recent Improvements to the IMPACT-T Parallel Particle Tracking Code	space-charge, simulation, electromagnetic-fields, cathode	185
	J. Qiang, I. V. Pogorelov, R. D. Ryne LBNL, Berkeley, California
	Funding: Supported in part by the US DOE, Office of Science, SciDAC program; Office of High Energy Physics; Office of Advanced Scientific Computing Research The IMPACT-T code is a parallel three-dimensional quasi-static beam dynamics code for modeling high brightness beams in photoinjectors and RF linacs. Developed under the US DOE Scientific Discovery through Advanced Computing (SciDAC) program, it includes several key features including a self-consistent calculation of 3D space-charge forces using a shifted and integrated Green function method, multiple energy bins for a beams with large energy spread, and models for treating RF standing wave and traveling wave structures. In this paper, we report on recent improvements to the IMPACT-T code including short-range transverse and longitudinal wakefield models and a longitudinal CSR wakefield model. Some applications will be presented including simulation of the photoinjector for the Linac Coherent Light Source (LCLS) and beam generation from a nano-needle photocathode.

WEPPP03	Recent Improvements of PLACET	simulation, ground-motion, collider, emittance	188
	A. Latina, L. Neukermans, G. Rumolo, D. Schulte CERN, Geneva P. Eliasson Uppsala University, Uppsala
	The tracking code PLACET simulates beam transport and orbit correction in linear colliders from the damping ring to the interaction point and beyond. It is a fully programmable and modular software, thanks to a Tcl interface and external modules based on shared libraries. Recent improvements of the code are presented, including the possibility to simulate bunch compressors and to use parallel computer systems.

WEPPP04	The FPP Documentation	site, resonance, lattice, beam-transport	191
	E. Forest, Y. Nogiwa KEK, Ibaraki F. Schmidt CERN, Geneva
	FPP is the FORTRAN90 library which overloads Berz’s “DA-package” and Forest’s “Lielib.” Furthermore it is also the library which implements a Taylor Polymorphic type. This library is essential to code PTC, the “Polymorphic Tracking Code.” Knowledge of the tools of FPP permits the computation of perturbative quantities in any code which uses FPP such as PTC/MAD-XP. We present here the available HTML documentation.

WEPPP10	Implementation of the DYNAMION Code to the End-To-End Beam Dynamics Simulations for the GSI Proton and Heavy Ion Linear Accelerators	rfq, simulation, ion, emittance	201
	S. Yaramyshev, W. Barth, L. A. Dahl, L. Groening, B. Schlitt GSI, Darmstadt
	The advanced multi-particle code DYNAMION is sufficient to calculate beam dynamics in linear accelerators and transport lines under space charge conditions with high accuracy. Special features like the consideration of field measurements, misalignment and fabrication errors, and data from the real topology of RFQ electrodes, drift tubes, quadrupole lenses lead to reliable results of the beam dynamics simulations. End-to-end simulations for the whole linac (from ion source extraction to the synchrotron entrance) allow for the investigation and optimization of the overall machine performance as well as for the calculation of the expected impact of different upgrade measures, proposed to improve beam brilliance. Recently the DYNAMION code is applied to investigate the beam dynamics for the different GSI-linacs: the heavy ion high current UNILAC, the high current proton linac for the future Facility for Antiproton and Ion Research at Darmstadt (FAIR), and the light ion accelerator for the cancer therapy (HICAT), to be commissioned in Heidelberg (Germany) in the near future. Recent results of the beam dynamics simulations by means of the DYNAMION code are presented. The proposed upgrade measures as well as tuning and optimization of the linacs are discussed.

WEPPP11	Comparison of the Beam Dynamics Designs for the FAIR High Current Proton LINAC-RFQ	rfq, emittance, proton, simulation	205
	S. Yaramyshev, W. Barth, L. A. Dahl, L. Groening GSI, Darmstadt A. P. Durkin MRTI RAS, Moscow S. Minaev ITEP, Moscow A. Schempp IAP, Frankfurt-am-Main
	The antiproton physics program for future Facility for Antiproton and Ion Research (FAIR) at Darmstadt is based on a rate of 7·10¹⁰ cooled antiprotons per hour. To provide sufficient primary proton intensities a new proton linac is planned. The proposed linac comprises an Electron Cyclotron Resonance (ECR) proton source, a Radio Frequency Quadrupole (RFQ), and Crossed-bar H-cavities (CH). Its operation frequency of 352 MHz allows for an efficient acceleration to up to 70 MeV using normal conducting CH-DTLs. The beam pulses with a length of 32 mks, a current of 70 mA, and total transverse emittances of 7 mkm will allow to fill the existing GSI synchrotron SIS 18 within one multi-turn-injection up to its space charge limit of 7·10¹² protons. Conceptual RFQ designs for two different RFQ types are proposed simultaneously: an RFQ of 4-rod type from the University Frankfurt and a 4 windows type RFQ from Institute for Theoretical and Experimental Physics (ITEP) and Moscow Radio-Technical Institute (MRTI). Studies of the beam dynamics in both RFQs has been done with the versatile multi-particle code DYNAMION. The topology of the RFQ tanks and electrodes is used "as to be fabricated" to provide for the realistic calculations of the external electrical field. The simulations are done under space charge conditions and including influence of the possible misalignments and errors of the fabrication. Simulated results for both designs will be discussed, as well as pros and cons. A comparison of the DYNAMION results with the simulations done by means of the PARMTEQM and LIDOS (dedicated codes for an RFQ design) is presented.

WEPPP12	New Developments of MAD-X UsingPTC	lattice, closed-orbit, controls, 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.

THM2IS02	The Universal Accelerator Parser	lattice, controls, 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.
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