Particle optics and accelerator modeling software for industrial andlaboratory beamline design

George H. Gillespie *, Barrey W. Hill

G.H. Gillespie Associates, Inc., P.O. Box 2961, Del Mar, CA 92014, USA

Abstract

The expanding variety of accelerator applications in research and industry places increased demands upon scientists

and engineers involved in developing new accelerator and beamline designs. Computer codes for particle optics simu-

lation have always played an important role in the design process and enhanced software tools o�er the promise of im-

proved productivity for beamline designers. This paper summarizes recent work on the development of advanced

graphic user interface (GUI) software components, that can be linked directly to many of the standard particle optics

programs used in the accelerator community, and which are aimed at turning that promise of improved productivity

into a reality. An object oriented programming (OOP) approach has been adopted and a number of GUI components

have been developed that run on several di�erent operating systems. The emphasis is on assisting users in the setup and

running of the optics programs without requiring any knowledge of the format, syntax, or similar requirements of the

input. The components are being linked with several popular optics programs, including TRANSPORT, TURTLE,

TRACE 3-D and PARMILA, to form integrated easy-to-use applications. Several advanced applications linking the

GUI components with Lie algebra and other high-order simulation codes, as well as system level and facility modeling

codes, are also under development. An overview of the work completed to date is presented, and examples of the new

tools running on the Windows 95 operating system are illustrated. Ó 1998 Elsevier Science B.V.

Keywords: Computer codes; Particle optics; Accelerator design; Graphic interface

1. Introduction

The varied applications of accelerators cover awide range of beam parameters and operating re-quirements. Each application often poses uniqueproblems for the designer and the particle opticsoptimization and simulation codes that he or she

uses. Several codes may be required to develop asound design; codes which typically have incom-patible input formats and con¯icting output capa-bilities. While there are a large number ofaccelerator and charged particle optics programsavailable, which have been extensively tested andbench marked on selected types of problems, theirapplication to a new problem is usually a dauntingchallenge to the non-expert. This paper summariz-es progress on the development of new softwaretools focused on improving the accessibility and

Nuclear Instruments and Methods in Physics Research B 139 (1998) 476±480

* Corresponding author. Tel.: +1 619 677 0076; fax: +1 619

677 0079; e-mail: ghga@millennianet.com.

0168-583X/98/$19.00 Ó 1998 Elsevier Science B.V. All rights reserved.

PII S 0 1 6 8 - 5 8 3 X ( 9 7 ) 0 0 9 4 0 - 3

ease of use of a large group of codes. These toolshad their genesis in a unique graphic user interfaceconcept named the Shell for Particle AcceleratorRelated Codes, or S.P.A.R.C. [1], and are now be-ing implemented in a second generation multi-plat-form (MP) renaissance of the concept, S.P.A.R.C.MP [2]. While the emphasis in this paper is on thenew tools available to users, it is useful to summa-rize some of the features and typical applicationsof the programs that have been integrated withS.P.A.R.C. and/or S.P.A.R.C. MP. A partial list-ing is given in Table 1. More details on each pro-gram can be found in Refs. [3±6].

2. Multi-platform shell for particle acceleratorrelated codes

The conceptual foundation for the new soft-ware tools is derived from a unique graphic userinterface designed speci®cally for codes used inthe accelerator community, known as S.P.A.R.C.[1]. A new MP version, S.P.A.R.C. MP, has beendeveloped to support a number of di�erent operat-ing systems [2]. An object oriented programming(OOP) approach has been adopted and the archi-tecture of the software has been developed specif-ically to run on several di�erent operatingsystems. S.P.A.R.C. MP is written in C++ and in-cludes an object model for describing beamlines [7]

useful for supporting di�erent accelerator model-ing codes.

3. The particle beam optics laboratory

The Particle Beam Optics Laboratory (PBOLab) is the ®rst commercially available software[8] developed with S.P.A.R.C. MP. The PBOLab [2,9] has four key elements: (1) a graphic userinterface shell, (2) a graphic beamline constructionkit for setting up design problems, (3) a set of helptutorials on the physics and technology of chargedparticle optical devices, and (4) several computa-tional engines that produce transfer matrices,beam envelopes and trajectories, ®t parameters tooptical constraints, and carry out similar calcula-tions for the graphically de®ned beam lines. The®rst element of the PBO Lab has been describedelsewhere [1,2,7]. The last three of these PBOLab elements are the focus of the remainder of thispaper. Fig. 1 illustrates selected windows from thePBO Lab beamline construction kit used for set-ting up a design problem on a Windows 95 com-puter.

3.1. De®ning beamlines in the PBO lab

One goal of the PBO Lab is to allow the setupand running of optics programs without requiringthe user to have any knowledge of the format orsyntax of the input needed by the program. Beam-lines and accelerator systems are graphically con-structed on the computer screen using drag anddrop icons. Default parameters are incorporatedfor all required inputs so that both the topologyof the beamline and a complete set of input dataare de®ned automatically during the graphicalconstruction. Setting up a particular design is re-duced to editing the values of parameters, whichare displayed in windows together with the param-eter descriptions. Di�erent parameter set optionsare available for de®ning optical elements, and avariety of units options may be used. Expert sys-tem type rules provide guidance for editing inputparameters, and additional displays, such as e�ec-tive focal lengths and phase space plots, provideusers with further useful feedback on their input.

Table 1

Beam optics and simulation codes working in the SPARC and/

or SPARC MP environments

Code name Selected characteristics and uses

TRANSPORT Third-order matrix code, magnetic optics

®tting options, optimization aberration

control

TURTLE Third-order ray tracing code, multi-particle

simulation of TRANSPORT designed

beamlines

TRACE 3-D First-order matrix & space charge, magnet-

ic, RF, electrostatic optics, ®tting, optimi-

zation, envelopes

PARMILA Multi-particle space charge code, magnetic

and RF optics, emittance growth, particle

loss

G.H. Gillespie, B.W. Hill / Nucl. Instr. and Meth. in Phys. Res. B 139 (1998) 476±480 477

Each beamline is initially built by selecting anddragging (with the mouse) icons from the PaletteBar and dropping them onto the Model SpacePane. Individual Pieces or groups of Pieces maybe selected for use in other beamline constructiontasks, such as dragging them to the Work SpacePane for future use. Pieces from the Work Spacemay be inserted into, or dropped onto the endsof, the beamline on the Model Space. SelectedPieces may also be de®ned as ``Sublines'' to beused, for example, in constructing beamlines com-posed of repetitive elements [7,9]. Sublines maycontain additional Sublines, as well as individualPieces. Fig. 1 illustrates a Model Space beamlinecomposed of Drifts and Quads, using Sublines.

A powerful object model has been developed[7], which very e�ciently describes either hierarchi-cal (Subline), ¯at (single Pieces), or mixed beam-line representations. This object model forms thebasis for the interactive graphic functionality andthe organization of the data ®les used to savebeamline descriptions. The model is especially suit-ed to representing machines with a large numberof repetitive components.

Parameter values are edited using Data Tablesin the Global Parameter Pane, in Piece Windowsfor individual beamline components, and in vari-

ous other PBO Lab Windows. A Piece Windowis accessed by ``double clicking'' on the icon ofthe desired beamline component. Fig. 1 illustratesthe Piece Window for the second Quad of the ®rstSubline. The Quad parameters can be edited usingany of three descriptions: ®eld gradient, pole tip®eld and aperture, or quadrupole coe�cient. thePBO Lab Piece Windows have several other fea-tures that assist users in editing input data, includ-ing a Tutorial linked to the data in the Window.

3.2. Help tutorials in the PBO lab

Another goal of the PBO Lab is to integrate aninformation and knowledge database on chargedparticle optics and the technologies and hardwareused in charged particle beamlines. Interactive,self-directed tutorials are used to present this ma-terial to the user. Much of the material developedfor the PBO Lab tutorials was utilized as part of aUS Particle Accelerator School (USPAS) opticscourse aimed at graduate and upper division un-dergraduate students.

The information presentation format consistsof two components: an interactive slide show anda hypertext component. The hypertext componentincludes narratives, graphics, equations, glossaries

Fig. 1. Windows from the graphical beamline construction kit of the S.P.A.R.C. MP PBO Lab.

478 G.H. Gillespie, B.W. Hill / Nucl. Instr. and Meth. in Phys. Res. B 139 (1998) 476±480

and similar content with many hypertext links.The slide show component presents conceptualgraphics and useful formulae with numerical re-sults for individual optics components that arebased upon the user's input parameters for that

component. The content of a given slide changesdynamically as the user modi®es relevant data inthe component's Piece Window. Selected windowsfor the quadrupole tutorial of the PBO Lab areshown in Fig. 2.

Fig. 2. Selected screens from the PBO Lab Tutorial for a magnetic quadrupole element.

Fig. 3. Graphic output from the TRANSPORT, TURTLE and trajectories modules of the PBO Lab.

G.H. Gillespie, B.W. Hill / Nucl. Instr. and Meth. in Phys. Res. B 139 (1998) 476±480 479

3.3. PBO lab computation engines and output

The primary computational engines in the PBOLab are the third-order TRANSPORT code, themultiple ray tracing program TURTLE, and anew ®rst-order matrix code that includes an enve-lope space charge model with support for calculat-ing single trajectories in the presence of the beamspace charge. Graphic results may be displayedon the screen without the need for additionalpost-processing. Fig. 3 illustrates examples of out-put from each of the three computation engines.

4. Summary

The S.P.A.R.C. MP concept promises im-proved productivity for scientists and engineers in-volved in the analysis or design of accelerators, aswell as a signi®cant reduction in the time requiredto train new researchers in the use of optics pro-grams. Substantial progress has been made in de-veloping the ®rst S.P.A.R.C MP softwareproduct, the PBO Lab, into a useful tool.

Acknowledgements

The authors are indebted to the developmentteam of Hendy Martono, John Moore, Chris Bab-cock and Mark Reed for their outstanding work inprototyping and writing the ®nal code used for thePBO Lab. Nathan Brown assisted in the develop-ment of prototype concepts and tutorials, and Mi-chael Lampel has contributed signi®cantly to thetesting, evaluation and concept improvement.

The assistance of James Gillespie in the design ofthe software architecture for the PBO Lab is grate-fully acknowledged. Portions of this work havebeen supported by the US Department of Energyunder SBIR grant number DE-FG03-94ER81767. Windows is a trademark of MicrosoftCorporation.

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480 G.H. Gillespie, B.W. Hill / Nucl. Instr. and Meth. in Phys. Res. B 139 (1998) 476±480