Tracing back measured magnetic field imperfections in LHC magnets by means of the inverse problem approach

Russenschuck, Stephan; Tortschanoff, T.; Ijspeert, A.; Perin, R.; Siegel, N.

doi:10.1109/20.305610

Cited by 5 publications

(2 citation statements)

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“…This means that the magnetic field must remain at 0 T to the left of the desired zero-field region (in the context of Figs. [5][6][7][8]. In this layout, the coil domain cannot completely enclose the desired high-field region, and care must be taken to force a zero field region adequately far into the charged particle approach (i.e., left of domain).…”

Section: Discussionmentioning

confidence: 99%

“…Insinga has reported extensively on the inverse design of magnet systems with an emphasis on the reciprocity theorem [1], [2], and a number of optimization methodologies have been reported across a range of magnet disciplines [3]- [6]. Instead of solving finite-element codes for the diffusion of magnetic potentials, coil-dominated superconducting (SC) magnets can be evaluated with computationally efficient Biot-Savart techniques for current-field inversion [7]- [14].…”

Section: Introductionmentioning

confidence: 99%

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Inverse Biot–Savart Optimization for Superconducting Accelerator Magnets

et al. 2021

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Superconducting (SC) magnets for accelerator concepts are often synthesized by numerically optimizing magnetic field waveforms, a process that requires a subsequent solution of a constrained inverse problem to identify suitable SC magnet windings. When the desired field distribution is intuitive, the inverse process is facilitated by seeding preconceived coil distributions into design optimization methods for refinement. With more complex magnetic field distributions, an initial design may be unknown, and topology optimization tools are required to synthesize current distributions without apriori guidance from a subject matter expert. In this work, we develop a constrained inverse Biot-Savart topology optimization methodology that synthesizes optimal distributions of current density in racetrack-like SC coils. The problem structure is exploited through a computationally efficient quadratic programming formulation, and the method is applied to recently published magnetic field waveforms for a recirculating proton phase shifter, a proton therapy gantry, and dipole magnets with sharp field transitions. The method and results herein identify novel winding configurations that can help magnet designers bring accelerator concepts to fruition.

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Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Inverse Biot–Savart Optimization for Superconducting Accelerator Magnets

et al. 2021

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Mathematical Optimization Techniques

Russenschuck¹

2010

Field Computation for Accelerator Magnets

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From the beginning the ROXIE program was structured such that mathematical optimization techniques can be applied to the design of the superconducting magnets. With the concept of features it is possible to create the complex coil assemblies in 2 and 3 dimensions with only a small number of engineering data which can then be addressed as design variables of the optimization problem. In this chapter some background information on the application of mathematical optimization techniques is given. Historical overviewMathematical optimization including numerical techniques such as linear and nonlinear programming, integer programming, network flow theory and dynamic optimization has its origin in operations research developed in world war II, e.g., Morse and Kimball 1950 [45]. Most of the real-world optimization problems involve multiple conflicting objectives which should be considered simultaneously, so-called vector-optimization problems. The solution process for vector-optimization problems is threefold, based on decision-making methods, methods to treat nonlinear constraints and optimization algorithms to minimize the objective function.Methods for decision-making, based on the optimality criterion by Pareto in 1896 [48], have been introduced and applied to a wide range of problems in economics by Marglin 1966 [42], Geoffrion 1968 [18] and Fandel 1972. The theory of nonlinear programming with constraints is based on the optimality criterion by Kuhn and Tucker, 1951 [37] -magnet. Girdinio, Molfino, Molinari and Viviani 1983 [20] optimized a profile of an electrode. These attempts tended to be application-specific, however. Only since the late 80 th, have numerical field calculation packages for both 2d and 3d applications been placed in an optimization environment. Reasons for this delay have included constraints in computing power, problems with discontinuities and nondifferentiabilities in the objective function arising from FE meshes, accuracy of the field solution and software implementation problems. A small selection of papers can be found in the references.The variety of methods applied shows that no general method exists to solve nonlinear optimization problems in computational electromagnetics in the same way that the simplex algorithm exists to 60

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Status of the fabrication and test of the prototype LHC lattice quadrupole magnets

et al. 1994

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reviewing the fabrication and validation tests of the design. describes the present state of the R 8: D work for the quadrupole magnet, 250 T/ m, is about 3.2 m long, with a coil aperture of 56 mm. This paper twin aperture prototype, working in liquid helium at 1.8 K, has a gradient of superconducting LHC prototype quadrupole at the Saclay laboratory. The to carry out, amongst others, the design, building, and testing of a R & D programme, CERN and CEN / Saclay have established a collaboration Within the framework of the Large Hadron Collider (LHC)

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Tracing back measured magnetic field imperfections in LHC magnets by means of the inverse problem approach

Cited by 5 publications

References 4 publications

Inverse Biot–Savart Optimization for Superconducting Accelerator Magnets

Inverse Biot–Savart Optimization for Superconducting Accelerator Magnets

Mathematical Optimization Techniques

Status of the fabrication and test of the prototype LHC lattice quadrupole magnets

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