Magnetic Shielding

Dr. Allard Schnabel, Physikalisch-Technische Bundesanstalt (PTB) Berlin, Germany

Details

  • Date: 13.02.2020
  • Time: 17:00 h
  • Place: SR I, Building C, Faculty of Engineering, Kaiserstr. 2., 24143 Kiel

 

Abstract

Environments where the magnetic field is far below the earth magnetic field of 50 µT are a prerequisite for many modern precision experiments. Active magnetic field compensation with coil systems can reduce the external fields by up to two orders of magnitude. Passive magnetic shielding enclosures out of highly permeable material (µr >> 1) can provide volumes of up to 1 m3 with less than 1 nT static magnetic field. In combination with very sensitive magnetic field detectors like SQUIDs and OPMs, numerous basic physics experiments as well as biological studies have been carried out. In the past the driving force for the development of magnetically shielded rooms was brain research due to the spatial and temporal resolution of the neuronal activity. Today the strongest requirements are from basic physics experiments e.g. the search for a finite electric dipole moment of the neutron. These experiments need a homogeneous field of a few µT which should not change by more than 10 fT within 100 s.

Starting from the basic principles of magnetic shielding, commercially available shields will be discussed before the limits of the strongest existing magnetically shielded rooms, like BMSR-2 at PTB, are presented. In praxis, a larger shielding factor is associated with several restrictions which limit the usage of such shields. The demagnetization process (degaussing), necessary to achieve a low static magnetic field inside the shield, will be discussed in detail. It will also be explained why an “equilibration” of the shielding material is needed to obtain a field stable in time when an additional magnetic field is switched on or used inside the chamber.

Website News

27.01.2020: Contributions on nerve signal modeling and magnetic muscle measurement by OPMs availaible on IEEE (early access).

27.01.2020: Talk about magnetic shielding by Allard Schnabel (PTB, Berlin) takes place on Feb 13, 2020, 17 h, Room: C-SR 1.

26.01.2020: Some reflections on the year 2019 are online now.

17.12.2019: Journal paper on signal processing for breathing protection masks published.

23.11.2019: GaS price 2019 for Jannek Winter for an excellent bachelor topic on underwater communication systems.

15.11.2019: Our new MIMO-SONAR system (sponsored by DFG) is now ready for "take off".

20.10.2019: We had a very good retreat on the island of Sylt.

07.08.2019: Talk from Juan Rafael Orozco-Arroyave added.

11.07.2019: First free KiRAT version released - a game for Parkinson patients

Recent Publications

   

E. Elzenheimer, H. Laufs, W. Schulte-Mattler, G. Schmidt: Magnetic Measurement of Electrically Evoked Muscle Responses with Optically Pumped Magnetometers, IEEE Transactions on Neural Systems and Rehabilitation Engineering, January 2020, doi: 10.1109/TNSRE.2020.2968148

   

M. Brodersen, A. Volmer, G. Schmidt: Signal Enhancement for Communication Systems Used by Firefighter, EURASIP Journal on Audio, Speech, and Music Processing, vol. 21, pp. 1 - 19, 2019

   

E. Elzenheimer, H. Laufs, W. Schulte-Mattler, G. Schmidt: Signal Modeling and Simulation of Temporal Dispersion and Conduction Block in Motor Nerves, IEEE Transactions on Biomedical Engineering, November 2019, doi: 10.1109/TBME.2019.2954592

Contact

Prof. Dr.-Ing. Gerhard Schmidt

E-Mail: gus@tf.uni-kiel.de

Christian-Albrechts-Universität zu Kiel
Faculty of Engineering
Institute for Electrical Engineering and Information Engineering
Digital Signal Processing and System Theory

Kaiserstr. 2
24143 Kiel, Germany

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