Research on the Performance Analysis and Precise Measurement of High-Performance Magnetic Shielding.
Measurement Systems
Final Report Abstract
Research with extremely small magnetic fields enabled extremely precise measurements of the spin precession of e.g. polarized noble gases, neutrons or the operation of quantum-sensors for the search of new physics beyond the known laws of nature within the last years. It also made it possible to detect bio-magnetic signals with unprecedented quality. With the advances of the sensitivity of the measurements and by tackling the fT-scale in accessible measurement technology new hurdles need to be overcome. This project posts a milestone in the development of ultra-low magnetic field measurements, as here the best shielded measurement environments with lowest background were realized as well as the – to our knowledge – the most sensitive spatial and temporal measurement methods and technology were implemented and characterized. The work packages of this project were shared between TUM and the Harbin Institute of technology, with Covid related travel restrictions to China. The success of the project was, however, not affected by this boundary condition and the cooperation with the Chinese partners was nevertheless fruitful. Next to guiding the installation and characterization of the new world-wide best shielded environment at HIT we could perform work in three areas: (i) quantitative modeling of extremely low and small applied fields and development of measurement techniques. Here, the numerical simulations of magnetic equilibration has been further developed, measurements of residual fields performed and the sensor calibration has been advanced such that spatial determination became experimentally possible; (ii) the investigation of the stability of small magnetic fields and the related issues of separation of measurement-artefacts and field specific features has been in-depth investigated. Using an array of optically pumped magnetometers, SQUID sensors and a stable current source, active feedback could be realized, making it possible to investigate small drifts independent of the bahvior of sensors. Further, Independent Component Analysis has been deployed to investigate noise sources in residual fields to further decrease noise in future; (iii) the development of long-term stable magnetic field sensors for the characterization of extremely stable magnetic fields has been pursued. Next to the characterization of self-made drift-stable sensors, also commercial sensors were tested at HIT, with the drift characterization being done at TUM in advance. The has been a plethora of valuable outcomes, of which some have been published already, further publications are still in preparation.
Publications
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Limits of Low Magnetic Field Environments in Magnetic Shields. IEEE Transactions on Industrial Electronics, 68(6), 5385-5395.
Sun, Zhiyin; Fierlinger, Peter; Han, Jiecai; Li, Liyi; Liu, Tianhao; Schnabel, Allard; Stuiber, Stefan & Voigt, Jens
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A highly drift-stable atomic magnetometer for fundamental physics experiments. Applied Physics Letters, 120(16).
Rosner, M.; Beck, D.; Fierlinger, P.; Filter, H.; Klau, C.; Kuchler, F.; Rößner, P.; Sturm, M.; Wurm, D. & Sun, Z.
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A lightweight magnetically shielded room with active shielding. Scientific Reports, 12(1).
Holmes, Niall; Rea, Molly; Chalmers, James; Leggett, James; Edwards, Lucy J.; Nell, Paul; Pink, Stephen; Patel, Prashant; Wood, Jack; Murby, Nick; Woolger, David; Dawson, Eliot; Mariani, Christopher; Tierney, Tim M.; Mellor, Stephanie; O’Neill, George C.; Boto, Elena; Hill, Ryan M.; Shah, Vishal ... & Bowtell, Richard
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A Small Scale Optically Pumped Fetal Magnetocardiography System. Journal of Clinical Medicine, 12(10), 3380.
Wurm, David; Ewert, Peter; Fierlinger, Peter; Wakai, Ronald; Wallner, Verena; Wunderl, Lena & Wacker-Gußmann, Annette
