Novel approach to filtering techniques in magnetic field measurements
Author
Nielsen, Kasper Vestergaard
Term
4. semester
Education
Publication year
2024
Submitted on
2024-08-08
Pages
78
Abstract
Accurate measurements of solenoids are essential for electron cooling, a technique that requires very uniform (flat) magnetic fields. This work presents and analyzes a new design of the translating fluxmeter developed at CERN, a device that measures magnetic flux by moving coils through the field. Tests show that the large coils perform well, while the smallest coils suffer from drift noise—slow, unwanted changes that are not part of the true signal. To address this, a customized filter combining a Kalman filter and a low-pass filter is designed for the fluxmeter. A simulation is used to estimate its performance and choose a filter design, and the approach is compared with state-of-the-art methods using a previously used dataset. The filter is then applied in the current measurement setup to improve the performance of the smallest coils. Experiments indicate that filtering can improve some signals, but Kalman filtering across different coils only makes sense when the relationships between their measurements are clearly defined. The study concludes that better magnetic field models are needed to make Kalman filtering more broadly useful in fluxmeter measurements.
Præcise målinger af solenoider er afgørende for elektronkøling, en metode der kræver meget ensartede (flade) magnetfelter. Dette arbejde præsenterer og analyserer et nyt design af det translaterende fluxmeter udviklet på CERN, et instrument der måler magnetisk flux ved at bevæge spoler gennem feltet. Test viser, at de store spoler fungerer godt, mens de mindste spoler er påvirket af driftstøj, dvs. langsomme, uønskede ændringer, som ikke er en del af det egentlige signal. For at afhjælpe dette er der udviklet et skræddersyet filter til fluxmeteret, der kombinerer et Kalman-filter og et lavpasfilter. En simulering bruges til at vurdere filterets ydeevne og vælge et filterdesign, og løsningen sammenlignes med tidens bedste metoder på et tidligere anvendt datasæt. Filteret anvendes derefter i den nuværende måleopstilling for at forbedre de mindste spolers ydeevne. Forsøgene viser, at filtrering kan forbedre nogle signaler, men at Kalman-filtrering på tværs af forskellige spoler kun giver mening, når relationerne mellem målingerne er klart defineret. Studiet konkluderer, at bedre feltmodeller er nødvendige for at gøre Kalman-filtrering mere anvendelig i fluxmetermålinger.
[This apstract has been rewritten with the help of AI based on the project's original abstract]
Keywords