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Magnetic Field Stabilization for Magnetically Shielded Volumes by External Field Coils
Summary
A new magnetic field stabilization system was developed for sensitive measurements like the neutron electric dipole moment (EDM). This system uses active coil control to suppress magnetic field fluctuations, achieving over 200x suppression.
Area of Science:
- Atomic, Molecular, and Optical Physics
- Experimental Particle Physics
- Geophysics and Environmental Science
Background:
- Highly sensitive magnetic measurements, such as neutron electric dipole moment (EDM) experiments, demand magnetic field stability below picoTesla.
- External magnetic field fluctuations pose a significant challenge to achieving the required precision in these experiments.
Purpose of the Study:
- To construct and characterize an external field coil system for stabilizing the ambient magnetic field at a predefined value.
- To actively stabilize the magnetic field along the axis of an EDM experiment, compensating for transverse field components.
Main Methods:
- Development of a system with four coils in a Helmholtz-like configuration for active axial field stabilization.
- Incorporation of additional coils for compensating transverse ambient magnetic field components.
- Characterization using static and moving magnetic sources within the PSI magnetic test facility.
Main Results:
- The constructed system actively stabilizes the magnetic field along the experimental axis.
- Observed magnetic field suppression factors exceeding 200.
- Demonstrated effectiveness in correcting for slow magnetic field disturbances relevant to long integration time experiments.
Conclusions:
- The developed external field coil system effectively achieves picoTesla-level magnetic field stabilization.
- This system is a crucial component for enabling highly sensitive magnetic measurements, including neutron EDM.
- The achieved performance validates the system's capability for precision scientific investigations.
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