Field Computation For Accelerator Magnets

Written by a leading expert on the electromagnetic design and engineering of superconducting accelerator magnets, this book offers the most comprehensive treatment of the subject to date. In concise and easy-to-read style, the author lays out both the mathematical basis for analytical and numerical field computation and their application to magnet design and manufacture. Of special interest is the presentation of a software-based design process that has been applied to the entire production cycle of accelerator magnets from the concept phase to field optimization, production follow-up, and hardware commissioning. Included topics: Technological challenges for the Large Hadron Collider at CERN Algebraic structures and vector fields Classical vector analysis Foundations of analytical field computation Fields and Potentials of line currents Harmonic fields The conceptual design of iron- and coil-dominated magnets Solenoids Complex analysis methods for magnet design Elementary beam optics and magnet polarities Numerical field calculation using finite- and boundary-elements Mesh generation Time transient effects in superconducting magnets, including superconductor magnetization and cable eddy-currents Quench simulation and magnet protection Mathematical optimization techniques using genetic and deterministic algorithms Practical experience from the electromagnetic design of the LHC magnets illustrates the analytical and numerical concepts, emphasizing the relevance of the presented methods to a great many applications in electrical engineering. The result is an indispensable guide for high-energy physicists, electrical engineers, materials scientists, applied mathematicians, and systems engineers.

The main topic of the book are the superconducting dipole and quadrupole magnets needed in high-energy accelerators and storage rings for protons, antiprotons or heavy ions. The basic principles of low-temperature superconductivity are outlined with special emphasis on the effects which are relevant for accelerator magnets. Properties and fabrication methods of practical superconductors are described. Analytical methods for field calculation and multipole expansion are presented for coils without and with iron yoke. The effect of yoke saturation and geometric distortions on field quality is studied. Persistent magnetization currents in the superconductor and eddy currents the copper part of the cable are analyzed in detail and their influence on field quality and magnet performance is investigated. Superconductor stability, quench origins and propagation and magnet protection are addressed. Some important concepts of accelerator physics are introduced which are needed to appreciate the demanding requirements on field quality in large storage rings. The operational experience with the superconducting HERA collider serves as an illustration. Finally superconducting correction coils and practical construction and fabrication methods of accelerator magnets are discussed. The physical and technical principles described in the book are substantiated with a wealth of experimental data on multipoles, persistent- and eddy-current effects, quench performance and much more. Contents:IntroductionBasics of SuperconductivityPractical Superconductors for Accelerator MagnetsField CalculationsMechanical Accuracies and Magnetic ForcesPersistent CurrentsEddy Current Effects in Superconducting MagnetsQuenches and Magnet ProtectionImpact of Field Errors on Accelerator Performance and Correction SchemesConstruction Methods of Superconducting Accelerator MagnetsA Techniques of Multipole MeasurementsStretched-Wire System for Quadrupole MeasurementsPassive Superconductor Magnetization in Beam-Pipe CoilsApproximate Relations for NbTi Critical ParametersHelium PropertiesMaterial Properties of KaptonCollar and Yoke Material Properties Readership: Engineers, research scientists and applied physicists. keywords:

This unique book, written by one of the world's foremost specialists in the field, is devoted to the design of low and medium field electromagnets whose field level and quality (uniformity) are dominated by the pole shape and saturation characteristics of the iron yoke. The wide scope covers material ranging from the physical requirements for typical high performance accelerators, through the mathematical relationships which describe the shape of two-dimensional magnetic fields, to the mechanical fabrication, assembly, installation, and alignment of magnets in a typical accelerator lattice. In addition, stored energy concepts are used to develop magnetic force relationships and expressions for magnets with time varying fields. The material in the book is derived from lecture notes used in a course at the Lawrence Livermore National Laboratory and subsequently expanded for the U.S. Particle Accelerator School, making this text an invaluable reference for students planning to enter the field of high energy physics. Mathematical relationships tying together magnet design and measurement theory are derived from first principles, and chapters are included that describe mechanical design, fabrication, installation, and alignment. Some fabrication and assembly practices are reviewed to ensure personnel and equipment safety and operational reliability of electromagnets and their power supply systems. This additional coverage makes the book an important resource for those already in the particle accelerator business as well as those requiring the design and fabrication of low and medium field level magnets for charged particle beam transport in ion implantation and medical applications.

This open access book is written by world-recognized experts in the fields of applied superconductivity and superconducting accelerator magnet technologies. It provides a contemporary review and assessment of the experience in research and development of high-field accelerator dipole magnets based on Nb3Sn superconductor over the past five decades. The reader attains clear insight into the development and the main properties of Nb3Sn composite superconducting wires and Rutherford cables, and details of accelerator dipole designs, technologies and performance. Special attention is given to innovative features of the developed Nb3Sn magnets. The book concludes with a discussion of accelerator magnet needs for future circular colliders.

Particle Accelerator Physics covers the dynamics of relativistic particle beams, basics of particle guidance and focusing, lattice design, characteristics of beam transport systems and circular accelerators. Particle-beam optics is treated in the linear approximation including sextupoles to correct for chromatic aberrations. Perturbations to linear beam dynamics are analyzed in detail and correction measures are discussed, while basic lattice design features and building blocks leading to the design of more complicated beam transport systems and circular accelerators are studied. Characteristics of synchrotron radiation and quantum effects due to the statistical emission of photons on particle trajectories are derived and applied to determine particle-beam parameters. The discussions specifically concentrate on relativistic particle beams and the physics of beam optics in beam transport systems and circular accelerators such as synchrotrons and storage rings. This book forms a broad basis for further, more detailed studies of nonlinear beam dynamics and associated accelerator physics problems, discussed in the subsequent volume.

Particle Accelerator Design: Computer Programs describes some of the most important computer programs applicable to the design of particle accelerators. Computer programs that calculate magnetic and electric fields are considered, along with programs that calculate orbits of particles in a magnetic and/or electric field. Some representative programs useful in the design of linear accelerator-type cavities are also discussed. This book is comprised of six chapters and begins with a review of two-dimensional magnetostatic programs, including TRIM, LINDA, NUTCRACKER, MAREC, GRACY, and COILS. The University of Colorado's magnet program is also examined. The next chapter is devoted to programs capable of solving problems relating to the calculation of electrostatic fields in two-dimensional geometries. The reader is also introduced to programs that perform calculations of three-dimensional linear and nonlinear problems, along with programs that employ matrix formalism and integration of equations of motion. The final chapter looks at programs for linear accelerator-type cavities, including CURE, JESSY, MESSYMESH, and AZTEC. This monograph will be a useful resource for physical scientists, engineers, and computer programmers.

This volume provides an overview of the state of the art in computational accelerator physics, based on papers presented at the seventh international conference at Michigan State University in October 2002. The major topics covered in this volume include particle tracking and ray tracing, transfer map methods, field computation for time dependent M

This monograph presents research on the transversal beam dynamics of accelerators and evaluates and describes the respective magnetic field homogeneity. The widely used cylindrical circular multipoles have disadvantages for elliptical apertures or curved trajectories, and the book also introduces new types of advanced multipole magnets, detailing their application, as well as the numerical data and measurements obtained. The research presented here provides more precise descriptions of the field and better estimates of the beam dynamics. Moreover, the effects of field inhomogeneity can be estimated with higher precision than before. These findings are further elaborated to demonstrate their usefulness for real magnets and accelerator set ups, showing their advantages over cylindrical circular multipoles. The research findings are complemented with data obtained from the new superconducting beam guiding magnet models (SIS100) for the FAIR (Facility for Antiproton and Ion Research) project. Lastly, the book offers a comprehensive survey of error propagation in multipole measurements and an appendix with Mathematica scripts to calculate advanced magnetic coil designs.