17–22 May 2026
C.I.D
Europe/Zurich timezone

Magnetic field reconstruction from sparse measurements for complex geometries

SUP5304
17 May 2026, 14:00
4h
C.I.D

C.I.D

Board: Sunday baguette: BD09
Student Poster Presentation MC5.D03: Calculations of EM fields Theory and Code Developments Student poster session

Speaker

Jack Phillips (Particle Beam Physics Lab (PBPL), University of California, Los Angeles)

Description

Precise 3D field measurements of large, complex magnet geometries are time-consuming and error-susceptible. For large magnets, it is common to record Hall probe data on a sparse grid, then use an interpolation algorithm to estimate field values at the remaining points. For common magnet geometries, such as quadrupoles and dipoles, linear interpolation often provides accurate results. However, for complex magnet geometries, this method can yield lower accuracy. In this paper, we present a method based on a locally Maxwell-consistent algorithm for sparse Hall probe measurements. Through the k-nearest neighbors algorithm, we locally fit the magnetic field with Tikhonov regularization. We test this method on a novel Compton spectrometer, capable of measuring single-shot, double-differential, energy-angle gamma spectra, ranging from 180 keV to 28 MeV. Using held-out validation, we demonstrate that we can reconstruct its magnetic fields with higher accuracy than linear interpolation and radial basis function (RBF) interpolation with cubic, thin plate spline, and quintic kernels. We also analyze the dependence of point sparsity on accuracy.

Funding Agency

The authors thank the Tigner Traineeship in Accelerator Science, DOE award DE-SC0024907, and the US Department of Energy, under Contract No. DE-SC0009914.

Paper status No proceeding expected (student session).

Author

Jack Phillips (Particle Beam Physics Lab (PBPL), University of California, Los Angeles)

Co-authors

Dr Brian Naranjo (University of California, Los Angeles) James Rosenzweig (University of California, Los Angeles) Phoebe Alva Rosa (Augsburg University) Joseph Phillips (MiraCosta College) Dr Doug McCormick (SLAC National Accelerator Laboratory) Douglas Storey (SLAC National Accelerator Laboratory) Juan Cruz Jr. (SLAC National Accelerator Laboratory)

Presentation materials

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