| Title |
Challenges in Extracting Pseudo-Multipoles From Magnetic Measurements |
| Authors |
- S. Russenschuck, G. Caiafa, L. Fiscarelli, M. Liebsch, C. Petrone, P. Rogacki
CERN, Geneva, Switzerland
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| Abstract |
Extracting the coefficients of Fourier-Bessel series, known as pseudo-multipoles or generalized gradients, from magnetic measurements of accelerator magnets involves technical and mathematical challenges. First, a novel design of a short, rotating-coil magnetometer is required that does not intercept any axial field component of the magnet. Moreover, displacing short magnetometers, step-by-step along the magnet axis, yields a convolution of the local multipole field errors and the sensitivity (test function) of the induction coil. The deconvolution must then content with the low signal-to-noise ratio of the measurands, which are integrated voltages corresponding to spatial flux distributions. Finally, the compensation schemes, as implemented on long coils used for measuring the integrated field harmonics, cannot be applied to short magnetometers. All this requires careful design of experiment to derive the optimal length of the induction coil, the step size of the scan, and the highest order of pseudo-multipoles in the field reconstruction. This paper presents the theory of the measurement method, the data acquisition and deconvolution, and the design and production of a saddle-shaped, rotating-coil magnetometer.
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| Paper |
download SUPAG03.PDF [8.897 MB / 6 pages] |
| Slides |
download SUPAG03_TALK.PDF [4.548 MB] |
| Export |
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| Conference |
ICAP2018 |
| Series |
International Computational Accelerator Physics Conference (13th) |
| Location |
Key West, FL, USA |
| Date |
20-24 October 2018 |
| Publisher |
JACoW Publishing, Geneva, Switzerland |
| Editorial Board |
Volker RW Schaa (GSI, Darmstadt, Germany); Kyoko Makino (MSU, East Lansing, MI, USA); Pavel Snopok (IIT, Chicago, IL, USA); Martin Berz (MSU, East Lansing, MI, USA) |
| Online ISBN |
978-3-95450-200-4 |
| Received |
18 October 2018 |
| Accepted |
27 January 2019 |
| Issue Date |
04 May 2019 |
| DOI |
doi:10.18429/JACoW-ICAP2018-SUPAG03 |
| Copyright |
 Published by JACoW Publishing under the terms of the Creative Commons Attribution 3.0 International license. Any further distribution of this work must maintain attribution to the author(s), the published article's title, publisher, and DOI. |
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